PHYTOECDYSONE FOR USE IN THE PREVENTION OF MUSCLE STRENGTH LOSS DURING IMMOBILIZATION

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the use of phytoecdysones and their derivatives for use in preventing loss of muscle strength during immobilization. STATE OF THE ART

[0002] The risk of complications following the immobilization of a limb or holding a lying position for a long term (decubitus) is significant and can manifest itself through muscular, but also bronchopulmonary, cardiovascular or osteoarticular disorders (Bodine 2013, Hermans & Van den Berghe 2015; De Jonghe et al. 2007; Wentworth et al. 2017; Lordens et al. 2017).

[0003] Immobilization can be gradual or sudden and can affect a limb or extend to the entire body in the most extreme cases. The circumstances leading to immobilization are numerous, for example: the fracture or injury of a limb leading to the installation of an external immobilization device (non-plaster restraints such as a neck brace, sling, Dujarrier-type bandage, metal or Zimmer splints, syndactyly or plaster restraints with complete or incomplete immobilization of a limb), a partial or total ligament rupture requiring or not requiring surgical intervention leading to the installation of an external immobilization device, the installation of a hip prosthesis, the installation of a knee prosthesis, orthopedic assemblies not allowing immediate weight-bearing, pelvic fracture during a painful period, fracture of the neck of the femur operated or not operated, stable or unstable, partial peripheral nerve damage due to trauma, partial spinal cord damage due to trauma, and patients placed in a decubitus position for a prolonged period.

[0004] In all cases, immobilization will lead to alterations in muscle tissue. There is a decrease in muscle mass, muscle wasting or amyotrophy, as well as a decrease in muscle strength and power, which generally leads to a period of incapacity and, in some cases, to a lengthening of care, resulting in an increase in hospital costs.

[0005] Skeletal muscle atrophy and strength loss following immobilization have functional consequences, particularly on posture and balance, which increases the risk of falling, particularly in the elderly (Onambele et al., 2006).

[0006] In France, the number of upper femur fractures in the elderly is estimated at between 50,000 and 80,000 per year. The vast majority of these femoral fractures are the result of falls (INSERM 2015). Femoral neck fractures lead to a temporary reduction in mobility, which can lead to complications. Femoral neck fractures are one of the leading causes of mortality in people over 65 (Gillespie et al. 2012). In the year following the accident, mortality is 10 to 20% higher than in subjects of the same age and sex. All causes combined, 20 to 30% of patients over 55 die within one year of a femoral neck fracture (Klop et al., 2014 and Lund et al., 2014).

[0007] In the elderly, muscle atrophy following immobilization has very serious consequences that can be aggravated by muscle atrophy linked to aging (sarcopenia). The mechanisms involved in muscle atrophy linked to aging and in muscle atrophy linked to immobilization are, however, different (reviews in Lynch et al., 2007; Romanick & Brown-Borg, 2013).

[0008] During immobilization, it can be observed that type I (oxidative) fibers are particularly affected by atrophy (Bigard et al., 1998; Ohira et al., 2006). In contrast, sarcopenia is manifested by a particular atrophy concerning type II (glycolytic) fibers, associated with the development of connective tissue (fibrosis) as well as infiltration by adipose cells (e.g., Nilwik et al., 2013). Sarcopenia is characterized by a decrease in fiber diameter and number (Lexell, 1993). In contrast, in the context of atrophy linked to immobilization, fiber size decreases but the number of muscle fibers remains constant (Narici, 2010). Furthermore, atrophy involves autophagy processes whose regulation differs depending on the type of fiber (Yamada et al., 2012).

[0009] The molecular mechanisms underlying induced muscle atrophy are also different. Some genes known to induce muscle atrophy, such as MuRF1 and Atrogin, can be activated by well-known signaling pathways such as NF- B. This signaling pathway is activated under conditions of atrophy linked to cachexia or immobilization (Hunter et al., 2002) but not in a context of sarcopenia (Bar-Shai et al., 2005; Phillips, 2005; Sakuma, 2012).

[0010] Myostatin, a negative regulator of muscle growth, increases during cachexia-related atrophy and immobilization, but this has not been shown to be the case in aged animals, in which myostatin levels remain relatively unchanged (Siriett et al., 2006; Lebrasseur et al., 2009).

[0011] Under these conditions, the fact that a substance is effective in treating sarcopenia does not mean that it will be effective in preventing muscle disorders linked to immobilization.

[0012] Immobilization also impacts recovery to peak physical performance, particularly in athletes (Milsom et al. 2014).

[0013] Plaster immobilization of an injured limb causes structural changes in the muscles affected by the immobilization. For example, two months of ankle immobilization led to a decrease in the volume of the triceps surae and quadriceps of 21.9% and 24.1% respectively. Two months after the lifting of immobilization, the two muscles were still 9.5% and 5.2% less voluminous than before immobilization (Grosset & Onambele-Pearson, 2008). In terms of muscle fiber surface area (CSA) cross-sectional area), five weeks of immobilization reduce CSA by 10 to 20% depending on the type of fibers and the muscles involved (Suetta et al. 2004; Berg et al. 2007). CSA of body weight-bearing muscles decreases by approximately 2-3% per week during the first months of immobilization (Berg et al. 2007).

[0014] Muscle strength is also significantly reduced following immobilization. Generally, immobilizing the leg for two weeks produces a loss of one-third of muscle strength in young people, while older subjects lose about a quarter of their strength. In the latter, the loss of muscle power can be irreversible. This can cause a loss of confidence and fragility that invariably leads to dependency. In addition, the onset of immobilization syndrome can result from bed rest or simply from a significant reduction in activity.

[0015] Patients bedridden for more than a week experience a loss of muscle strength in their antigravity calf and back muscles (Hermans and Van den Berghe, 2015). In healthy humans, during the first week of bed rest, strength losses of between 1% and 6% per day have been observed (Appell, 1990). A period of 1 to 2 weeks of lower limb inactivity induces a 15% reduction in knee extensor strength in subjects in their twenties.

[0016] Furthermore, a study showed that wearing a cast for 5 days caused a 9% loss of quadriceps strength, while this loss reached 23% after 14 days of immobilization. Bed rest for 3 months has very marked effects on the strength developed, with a decrease of 31% to 60% depending on the muscle considered (Alkner & Tesch, 2004).

[0017] The highlighting of the deleterious role of muscle immobilization has led to testing the feasibility and effectiveness of several preventive methods. Thus, in certain cases, in order to compensate for muscle damage caused by immobilization, early active or passive remobilization programs for patients are implemented. These programs have the disadvantage of being difficult to implement on a large scale. In addition, the use of these methods is delicate, even impossible in certain surgical patients for whom mobilization proves painful.

[0018] Muscle electrostimulation studies have also been conducted, but this approach does not provide a systemic beneficial effect of stimulation, it may be ineffective in patients with inexcitability of the muscle membrane and the choice of the muscle territory to stimulate is delicate in cases of extensive immobilization.

[0019] In addition to the tissue and mechanical changes in the muscle during immobilization, major metabolic and molecular changes also occur.

[0020] Thus, protein synthesis is decreased, while immobilization causes an increase in oxidative stress, inflammation, apoptosis as well as the activation of proteolytic pathways that lead to the degradation of muscle proteins.

[0021] Phytoecdysones represent a large family of polyhydroxy sterols. These molecules are produced by various plant species and participate in their defense against pests. The predominant phytoecdysone in the plant kingdom is 20-hydroxyecdysone.

[0022] Studies have highlighted the antidiabetic and anabolic properties of certain phytoecdysones. Stimulating effects on protein synthesis in muscles have been observed in rats. in vivo(Syrov, 2000; Tôth et al., 2008; Lawrence, 2012) and on murine C2C12 myotubes in vitro (Gorelick-Feldman et al., 2008).

[0023] Semi-synthetic derivatives of 20-hydroxyecdysone have been proposed in the publication of the applicant company's French patent application, published under number FR3021318A1, and in international patent application WO 2015 / 177469. Their use as a medicament for the treatment and / or prevention of sarcopenia and in particular sarcopenic obesity, its complications and / or associated pathologies such as loss of strength, muscle mass, physical performance and capacity and mobility in mammals is also mentioned therein.

[0024] Furthermore, international patent application WO2016 / 166480 discloses the use of 20-hydroxyecdysone derivative compounds for the treatment or prevention of muscle atrophy in mammals, which muscle atrophy may be related to immobilization. SUBJECT OF THE INVENTION

[0025] The present invention aims to limit as much as possible the loss of muscular strength during immobilization, particularly following, for example, a fracture, bed rest or simply a significant reduction in activity.

[0026] The inventors discovered that phytoecdysones and their derivatives protect against muscle strength loss associated with immobilization. Muscle strength is defined as the absolute and specific maximum isometric force of skeletal muscle.

[0027] Unexpectedly, phytoecdysones and their derivatives significantly reduce the loss of muscle strength associated with immobilization without this property being linked to an anabolic effect on skeletal muscle.

[0028] In the remainder of the description, the term “phytoecdysones” and their derivatives means plant extracts rich in 20-hydroxyecdysone, and compositions comprising 20-hydroxyecdysone as the active agent.

[0029] The said plant extracts rich in 20-hydroxyecdysone are, for example, extracts of Stemmacantha carthamoides or Cyanotis vaga.

[0030] The extracts obtained are preferably purified to pharmaceutical grade.

[0031] The invention relates to a composition comprising at least: 20-hydroxyecdysone; or at least one compound of general formula (I): in which: R 1< is chosen from: a group (C 1 -C 6 ) W (C 1 -C 6 ); a grouping (C 1 -C 6 ) W (C 1 -C 6 ) W (C 1 -C 6 ); a grouping (C 1 -C 6 ) W (C 1 -C 6 )CO 2 (C 1 -C 6 ); a (C 1 -C 6 ) group A , A representing a heterocycle optionally substituted by a group chosen from OH, OMe, (C 1 -C 6 ), N(C 1 -C 6 ), CO 2 (C 1 -C 6 ); a CH 2 Br group, W being a heteroatom chosen from N, O and S, preferably O and even more preferably S; or, at least one compound of formula (II): for its use in mammals for the prevention of loss of muscle strength during immobilization.

[0032] An example of such a composition is the pharmaceutical grade purified extract BIO101 developed by the applicant. BIO101 is a plant extract, said plant being selected from plants containing at least 0.5% of 20-hydroxyecdysone by dry weight of said plant, said extract comprising at least 95%, and preferably at least 97%, of 20-hydroxyecdysone.

[0033] In embodiments the composition comprises a compound selected from the following compounds: n° 1 : (2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-10,13-dimethyl-17-(2-morpholinoacetyl)-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one, n° 2 : (2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-17-[2-(3-hydroxypyrrolidin-1-yl)acetyl]-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 3: (2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-17-[2-(4-hydroxy-1-piperidyl)acetyl]-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 4 : (2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-17-[2-[4-(2-hydroxyethyl)-1-piperidyl]acetyl]-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 5 : (2S,3R,5R,10R,13R,14S,17S)-17-[2-(3-dimethylaminopropyl (methyl)amino)acetyl]-2,3,14-trihydroxy-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 6 : 2-[2-oxo-2-[(2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-10,13-dimethyl-6-oxo-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-17-yl]ethyl]sulfanylacetate; n° 7 : (2S,3R,5R,10R,13R,14S,17S)-17-(2-ethylsulfanylacetyl)-2,3,14-trihydroxy-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 8 :(2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-17-[2-(2-hydroxyethyl sulfanyl)acetyl]-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H cyclopenta[a]phenanthren-6-one.

[0034] In embodiments the composition is incorporated into an acceptable pharmaceutical formulation suitable for oral administration.

[0035] In embodiments, the phytoecdysones are administered at a dose of between 50 and 1000 milligrams per day in humans.

[0036] In embodiments, the compound of formula (II) is administered at a dose of between 50 and 1000 milligrams per day in humans.

[0037] In embodiments, the composition is administered during immobilization. Preferably, the composition is administered from the first day of immobilization.

[0038] In embodiments, the composition is administered until the immobilization is released.

[0039] In embodiments, the composition is further administered within a predetermined time period after the immobilization is released.

[0040] In an exemplary embodiment, the predetermined duration of treatment after the lifting of the immobilization corresponds to the time required to recover a force threshold corresponding for example to 80% or 100% of the subject's estimated initial force.

[0041] In an exemplary embodiment, the predetermined treatment duration corresponds to a period of at least 28 days.

[0042] In an exemplary embodiment, the predetermined treatment duration corresponds to a period of three to six months.

[0043] Preferably, treatment after lifting the immobilization is supplemented by a physical exercise program. PRESENTATION OF FIGURES

[0044] Other particular advantages, aims and characteristics of the present invention will emerge from the following non-limiting description of at least one particular embodiment of the subject of the present invention, with reference to the appended drawings, in which: There Figure 1A is a representative image of hematoxylin and eosin-stained histological sections of non-immobilized C57BL / 6J genetic background mouse tibialis anterior (TA) muscle. Figure 1B is a representative image of hematoxylin-eosin stained histological sections of tibialis anterior muscle from C57BL / 6J genetic background mice immobilized and treated with vehicle for 14 days, The Figure 1C is a representative image of hematoxylin-eosin stained histological sections of anterior tibial muscle from C57BL / 6J genetic background mice immobilized and treated with the compound of formula (II) for 14 days. Figure 1Dis a representative diagram of the muscle fiber area of ​​the tibialis anterior muscle of C57BL / 6J genetic background mice that were non-immobilized (control), immobilized and treated with vehicle for 14 days, or immobilized and treated with a compound of formula (II) for 14 days. Figure 2A is a representative diagram of the weight of the tibialis anterior muscle of groups of mice of C57BL / 6J genetic background not immobilized (control), immobilized and treated with the vehicle for 14 days or immobilized and treated with the compound of formula (II) for 14 days. Figure 2B is a representative diagram of the gastrocnemius muscle weight of groups of C57BL / 6J genetic background mice that were non-immobilized (control), immobilized and treated with vehicle for 14 days, or immobilized and treated with the compound of formula (II) for 14 days. Figure 3Arepresents the absolute maximum isometric force of the anterior tibialis muscle of mice with a C57BL / 6J genetic background at different times post immobilization: non-immobilized (D0), after 14 days of immobilization (D14), after 14 days of immobilization and 1 week of remobilization (D21) or after 14 days of immobilization and 2 weeks of remobilization (D28), treated with the vehicle or with the compound of formula (II). Figure 3B represents the specific maximum isometric force of the anterior tibialis muscle of mice with a C57BL / 6J genetic background at different times post immobilization: non-immobilized (D0), after 14 days of immobilization (D14), after 14 days of immobilization and 1 week of remobilization (D21) or after 14 days of immobilization and 2 weeks of remobilization (D28), treated with the vehicle or with the compound of formula (II). Figure 4Ais a representative diagram of the weight of the tibialis anterior muscle of the groups of mice with a C57BL / 6J genetic background that were not immobilized (control, measured at D0 on non-immobilized animals), immobilized and treated with the vehicle for 14 days or immobilized and treated with the BIO101 compound for 14 days. Figure 4B is a representative diagram of gastrocnemius muscle weight of groups of C57BL / 6J genetic background mice that were non-immobilized (control), immobilized and treated with vehicle for 14 days, or immobilized and treated with BIO101 compound for 14 days. Figure 5A is a representative diagram of the absolute maximum isometric force of the tibialis anterior muscle of non-immobilized C57BL / 6J genetic background mice (control, measured at D0 on non-immobilized animals), immobilized and treated with vehicle for 7 days or immobilized and treated with BIO101 compound for 7 days. Figure 5Bis a representative diagram of the specific maximal isometric force of the tibialis anterior muscle of non-immobilized C57BL / 6J genetic background mice (control, measured at D0 on non-immobilized animals), immobilized and treated with vehicle for 7 days or immobilized and treated with BIO101 compound for 7 days. Figure 6A represents the absolute maximum isometric force of the anterior tibialis muscle of mice with a C57BL / 6J genetic background at different times post immobilization: non-immobilized (D0), after 7 days of immobilization (D7), after 14 days of immobilization (D14), and after 14 days of immobilization followed by 2 weeks of remobilization (D28), treated with the vehicle or with the BIO101 compound. Figure 6Brepresents the specific maximum isometric force of the anterior tibialis muscle of mice with a C57BL / 6J genetic background at different times post immobilization: non-immobilized (D0), after 7 days of immobilization (D7), after 14 days of immobilization (D14), after 14 days of immobilization then 2 weeks of remobilization (D28), treated with the vehicle or with the BIO101 compound. DETAILED DESCRIPTION OF THE INVENTION Process for the synthesis of the compound of formula (II)

[0045] The compound of formula (II) referred to in the remainder of the description is as follows:

[0046] The compound of formula (II) is obtained by semi-synthesis from 20-hydroxyecdysone then purification to pharmaceutical grade.

[0047] The process for preparing the compound of formula (II) by semi-synthesis comprises in particular: a step of oxidative cleavage of the side chain of 20-hydroxyecdysone between carbons C20 and C22 to obtain the poststerone, a step of introduction of a bromine atom at position C21, and a step of reaction of the brominated derivative with ethanethiol. Biological activity of the compound of formula (II)

[0048] A hindlimb immobilization model of a mouse with a C57BL / 6J genetic background was implemented using a tube (Lang et al., 2012).

[0049] Thirteen-week-old female C57BL / 6J mice were used. Ten mice were sacrificed on day 0; these mice were not immobilized to serve as controls.

[0050] D0, D14, D21, D28 are the time elapsed from the start of the experiment, expressed in days. Thus, D0 designates the start of the experiment (before treatment and before immobilization), D14 designates the 14th day from the start of the experiment, etc.

[0051] Two groups of mice were formed, a test group and a control group. Each group was chronically exposed orally to either the vehicle (control group) or the compound of formula (II) at a dose of 50 mg / kg per day (test group). The 28-day oral treatment consisted of gavage for five days per week and in the drinking water two days per week.

[0052] Animals in all groups were tested for their functional capacity in situ through measurements of absolute and specific maximal isometric strength of the tibialis anterior (TA) muscle ( Figures 3A and 3B ) after 14 days of immobilization (n=13 for the vehicle, n=10 for the compound of formula (II)), after 14 days of immobilization and 1 week of remobilization (n=7 for the vehicle, n=8 for the compound of formula (II)) and after 14 days of immobilization and two weeks of remobilization (n=6 for the vehicle, n=8 for the compound of formula (II)). Histology and muscle atrophy (Figure 1)

[0053] A histological study of the tibialis anterior muscle is carried out on sections stained with hematoxylin Eosin (HE). The area of ​​the muscle fibers is evaluated on muscles of control mice, or treated with the vehicle or with the compound of formula (II). The muscle presents in all cases a histology of healthy muscle tissue ( Figure 1 A to C ); on the other hand, as expected, after 14 days of immobilization, the average fiber area is significantly reduced in animals receiving the vehicle compared to control animals (-24.4%, p=0.006) which were not immobilized. The muscle fiber area of ​​the group treated with the compound of formula (II) is also reduced compared to the control group (-26.8%, p=0.002).

[0054] Therefore, no significant difference was observed between the groups of animals treated with the vehicle and the group treated with the compound of formula (II) (p=0.73). After 14 days of immobilization, the compound of formula (II) therefore did not exert a protective effect against the loss of muscle volume. Weight of the tibialis anterior (TA) and gastrocnemius muscles (Figure 2)

[0055] The weight of the TA muscles ( Figure 2A ) and gastrocnemius ( Figure 2B ) were evaluated in non-immobilized mice (control), and after 14 days of immobilization in mice treated either with the vehicle or with the compound of formula (II), during the 14 days of immobilization.

[0056] As expected, immobilization was observed to cause a decrease in TA and gastrocnemius muscle mass in mice receiving the vehicle compared to the control group (-34.9%, p<0.001 and -29%, p<0.001 respectively).

[0057] It is observed that the weight of the TA and gastrocnemius muscles does not vary significantly in the group of mice treated with the compound of formula (II) compared to the vehicle. Consistent with the results obtained on the diameter of the muscle fibers ( Figure 1 ), the compound of formula (II) therefore does not exert a protective effect against loss of muscle mass following immobilization. Absolute and specific maximal isometric strength of the tibialis anterior muscle (in situ functional study (Figure 3)

[0058] An assessment of the in situ contractility of the TA muscle is carried out at different times of the protocol: on non-immobilized control mice (D0), on mice subjected to hind paw immobilization for 14 days (D14), immobilized for 14 days then remobilized for 1 week (D21) and immobilized for 14 days then remobilized for 2 weeks (D28).

[0059] On the day of sacrifice, the mouse was anesthetized with an intraperitoneal injection of pentobarbital (55 mg / kg, 0.1 mL / 10 g body weight) before in situ force measurement of the tibialis anterior (TA) muscle. The skin on the upper leg was incised, exposing the tendon, which was severed at its distal end. The distal TA tendon was attached to the servomotor lever (305B Dual-Mode Lever, Aurora Scientific). The skin on the lateral aspect of the thigh was incised, exposing the sciatic nerve, between two muscle groups. The sciatic nerve was stimulated with a bipolar electrode (supramaximal 10V square wave pulse, 0.1 ms). Force was measured during contractions in response to electrical stimulation (frequency of 75-150 Hz, duration of 500 ms). The mouse temperature was maintained at 37°C using a radiant lamp. The absolute maximum isometric strength is measured ( Figure 3A ) and the specific isometric maximum strength ( Figure 3B ) is calculated by relating the absolute isometric force to the weight of the tibialis anterior muscle.

[0060] As expected, it was found that the animals treated with the vehicle had a significantly lower absolute isometric maximum contraction force than the non-immobilized control animals (-65.6%, p<0.001) ( Figure 3A ). Animals treated with the compound of formula (II) exhibited less absolute strength loss (-26.9%, p=0.015) compared to the control, than animals treated with the vehicle.

[0061] Surprisingly, it is observed that treatment with the compound of formula (II) allows animals immobilized for 14 days to maintain a significantly greater absolute isometric force than animals treated with the vehicle and improves their performance (+112.1%, p=0.0041). This is despite the absence of effect of the compound of formula (II) on the proportion of muscle mass and volume observed previously.

[0062] It is observed that animals treated with the vehicle have a specific maximal isometric contraction force (sP0; Figure 3B) significantly less than that of non-immobilized control animals (-57.8%, p<0.001). Remarkably, the specific force of animals treated with the compound of formula (II) is not significantly affected by immobilization: -8% (p=0.32) compared to animals in the control group, not immobilized. Treatment with the compound of formula (II) allows animals immobilized for 14 days to maintain normal muscle function by doubling the specific isometric force (+117.6%, p<0.001) compared to animals in the immobilized group, treated with the vehicle. Biological activity of compound BIO101

[0063] A second study was conducted using the same procedure of immobilizing both hind legs, on mice of the same age (13 weeks) and genetic background (C57BL / 6J) as described previously, but adding an analysis point after 7 days of immobilization. The analysis points are therefore D0, D7, D14 and D28.

[0064] Ten mice were sacrificed on D0; these mice were not immobilized to serve as controls (control group in the figures).

[0065] D7, D14, D28 are the time elapsed from the start of the experiment, expressed in days. Thus, D7 designates the 7th day from the start of the experiment, etc.

[0066] Two groups of mice were formed, a test group and a control group. Each group is exposed, orally, chronically either to the vehicle (control group) or to the compound BIO101 at a dose of 50 mg / kg per day (test group). Compound BIO101 is understood to mean a plant extract, said plant being chosen from plants containing at least 0.5% of 20-hydroxyecdysone by dry weight of said plant, said extract comprising as active agent 20-hydroxyecdysone in an amount of at least 95%, and preferably at least 97% by weight relative to the total weight of the extract. The oral treatment for 28 days consists of gavage five days per week and administration in the drinking water two days per week.

[0067] Animals in all groups were tested for functional capacity in situ (both hindlimbs) using absolute and specific maximal isometric strength measurements of the tibialis anterior (TA) muscle ( Figures 6A and 6B ) after 7 days of immobilization (n=6 mice, 2 values ​​per mouse for the control group (vehicle), n=6 mice, two values ​​per mouse for the test group (BIO101), after 14 days of immobilization followed by two weeks of remobilization (n=6 per mouse, two values ​​per mouse for the vehicle (control group), n=6 mice, two values ​​per mouse for the BIO101 compound), and after 14 days of immobilization followed by two weeks of remobilization (n=6 per mouse, two values ​​per mouse for the vehicle (control group), n=6 mice, two values ​​per mouse for the BIO101 compound). Weight of the tibialis anterior (TA) and gastrocnemius muscles (Figure 4)

[0068] The weight of the TA muscles ( Figure 4A ) and gastrocnemius ( Figure 4B) were evaluated in non-immobilized mice (control group), and after 14 days of immobilization in mice treated either with the vehicle or with the BIO101 compound for the entire duration of immobilization. As expected, immobilization was observed to cause a decrease in TA muscle mass (-21.7%, p<0.001) in mice receiving the vehicle compared to the non-immobilized control group ( Figure 4A ).

[0069] It is observed that the weight of the TA and gastrocnemius muscles does not vary significantly in the test group of mice treated with the BIO101 compound compared to the vehicle-treated control group ( Figure 4A and 4B ). Absolute and specific maximal isometric strength of the tibialis anterior muscle (in situ functional study (Figures 5 and 6)

[0070] An assessment of the in situ contractility of the TA muscle is carried out at different times of the protocol: on non-immobilized control mice (control group, D0), on mice subjected to immobilization of the hind legs for 7 days (D7), 14 days (D14), immobilized for 14 days then remobilized for 2 weeks (D28).

[0071] When considering the force developed by the TA muscle after seven days of immobilization, as expected, it is observed that the animals treated with the vehicle (control group) have a significantly lower absolute isometric maximum contraction force than that of the non-immobilized control animals (-34.7%, p<0.001) ( Figure 5A ). Animals treated with BIO101 compound exhibited less absolute strength loss (-21.1%, p=0.001) compared to control, than animals treated with vehicle ( Figure 5A ).

[0072] Interestingly, it is observed that treatment with the BIO101 compound allows animals immobilized for 7 days to maintain a significantly greater absolute isometric maximum force and improves their performance (+21%, p=0.01) compared to animals treated with the vehicle, despite the absence of effect of the BIO101 compound on mass loss.

[0073] It is observed that animals treated with the vehicle have a specific maximal isometric contraction force (sP0; Figure 5B) significantly less than that of non-immobilized control animals (-13.2%, p<0.01). Remarkably, the specific maximal isometric force of animals treated with the BIO101 compound is not significantly affected by 7 days of immobilization: in fact, treatment with the BIO101 compound allows animals immobilized for 7 days to maintain normal muscle function compared to animals in the immobilized group, treated with the vehicle (+24.3%, p<0.001).

[0074] At the time of lifting of immobilization, on D14, mice receiving BIO101 treatment lost only 22.4% (p<0.001) of absolute maximal isometric strength compared to non-immobilized control mice (D0), compared to 34% (p<0.001) for mice receiving the vehicle. Treatment with BIO101 limits the loss of absolute maximal isometric strength (+17.5%, p<0.05) compared to mice treated with the vehicle ( Figure 6A ).

[0075] Regarding specific maximal isometric strength, mice receiving BIO101 treatment did not lose strength 14 days post-immobilization compared to non-immobilized control mice (+5%, 2.94g / mg versus 2.80g / mg respectively, p=ns).

[0076] Vehicle-treated mice, on the other hand, lost 11.3% of their specific strength compared to non-immobilized mice (p=0.06).

[0077] After 14 days of immobilization, treatment with BIO101 tends to limit the loss of specific maximum force (+18.4%, ns) compared to mice treated with the vehicle ( Figure 6B ). Conclusion

[0078] Given the properties of phytoecdysones and their derivatives on the muscle function of mammals subjected to immobilization, the use of phytoecdysones and their derivatives can therefore be proposed to preserve muscle function, particularly with regard to muscle strength, and thus slow down the loss of muscle functions linked to immobilization. References

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Claims

1. - Composition including at least: - 20-hydroxyecdysone; or, - at least one compound of general formula (I): wherein: R1 is chosen from: a (C1-C6)W(C1-C6) group; a (C1-C6)W(C1-C6)W(C1-C6) group; a (C1-C6)W(C1-C6)CO2(C1-C6) group; a (C1-C6)A group, A representing a heterocycle optionally substituted by a group chosen from OH, OMe, (C1-C6), N(C1-C6), CO2(C1-C6); a CH2Br group; W being a heteroatom chosen from N, O and S, preferably O and even more preferentially S; or, - at least a compound of formula (II): for use thereof in mammals for preventing loss of muscle strength during immobilisation.

2. - Composition for use thereof according claim 1, which comprises a compound chosen from the following compounds: n° 1: (2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-10,13-dimethyl-17-(2-morpholinoacetyl)-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one, n° 2: (2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-17-[2-(3-hydroxypyrrolidin-1-yl)acetyl]-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 3: (2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-17-[2-(4-hydroxy-1-piperidyl)acetyl]-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 4: (2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-17-[2-[4-(2-hydroxyethyl)-1-piperidyl]acetyl]-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 5: (2S,3R,5R,10R,13R,14S,17S)-17-[2-(3-dimethylaminopropyl (methyl)amino)acetyl]-2,3,14-trihydroxy-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 6: ethyl 2-[2-oxo-2-[(2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-10,13-dimethyl-6-oxo-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-17-yl]ethyl]sulfanylacetate; n° 7: (2S,3R,5R,10R,13R,14S,17S)-17-(2-ethylsulfanylacetyl)-2,3,14-trihydroxy-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-6-one; n° 8: (2S,3R,5R,10R,13R,14S,17S)-2,3,14-trihydroxy-17-[2-(2-hydroxyethyl sulfanyl)acetyl]-10,13-dimethyl-2,3,4,5,9,11,12,15,16,17-decahydro-1H cyclopenta[a]phenanthren-6-one.

3. - Composition for use thereof according to any of the preceding claims, in a form incorporated in a pharmaceutically acceptable formulation suitable for oral administration.

4. - Composition for use thereof according to any one of the preceding claims, wherein the phytoecdysones are administered at a dose of between 50 and 1000 milligrams per day in humans.

5. - Composition for use thereof according to any one of the preceding claims, administered during immobilisation.

6. - Composition for use thereof according to any one of the preceding claims, administered until immobilisation ends.

7. - Composition for use thereof according to either one of claims 5 or 6, also administered during a predetermined period after ending of immobilisation.