Lactococcus lactis subsp. lactis JYLL-51 for improving sarcopenic obesity, its bacterial agent and application

Abstract

The present invention relates to the field of microbial technology, and specifically relates to Lactococcus lactis subsp. JYLL-51 for improving sarcopenic obesity, its bacterial agent and application. Lactococcus lactis subsp. ( Lactococcus lactis subsp. lactis ) JYLL-51 was deposited at the General Microbiological Center of the China National Center for Culture Collection of Microorganisms on March 13, 2024. The deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC NO. 30016. The present invention provides a Lactococcus lactis subsp. JYLL-51. Experiments show that the Lactococcus lactis subsp. JYLL-51 bacterial agent prepared from this strain can not only increase skeletal muscle weight and strength, but also reduce high-fat-induced fat accumulation, and can significantly improve sarcopenic obesity.

Description

Technical Field

[0001] The present invention relates to the field of microbial technology, and particularly to Lactococcus lactis subsp. JYLL-51 for improving sarcopenic obesity, its bacterial agent and application. Background Art

[0002] Sarcopenic obesity (SO) is a disease in which obesity and sarcopenia coexist and are age-related. Among them, sarcopenia is an age-related geriatric syndrome characterized by reduced muscle mass, decreased muscle strength, and / or impaired physical function, and obesity is abnormal or excessive fat accumulation that may damage health. Sarcopenic obesity can lead to falls, unsteady walking, balance disorders, fractures in the elderly, increase the all-cause mortality of patients and the social medical burden, and its pathogenesis is relatively complex. Current research believes that it is closely related to aging, unhealthy lifestyles, eating habits, etc.

[0003] Currently, the commonly used method for improving sarcopenic obesity is to intervene in the lifestyle of the elderly. On the one hand, fat loss and muscle gain can be achieved by restricting energy intake and supplementing sufficient protein. Each meal should contain at least 25 - 30 g of protein, taking into account both quantity and weight to stimulate muscle protein synthesis. During the fat loss process, ensure sufficient intake of vitamins and minerals to avoid the occurrence of malnutrition. On the other hand, reasonable exercise can effectively maintain muscle mass and muscle strength and reduce visceral fat. On the premise of ensuring safety, the elderly population can perform 150 minutes of moderate-intensity exercise per week. However, the reality is that due to restrictions such as economic level, ideological concepts, and physical conditions, most elderly people are difficult to maintain healthy eating habits and fitness habits for a long time. The elderly population remains a high-risk group for sarcopenic obesity. Summary of the Invention

[0004] Aiming at the technical problem that sarcopenic obesity is prone to occur in the elderly population, but it is difficult for the elderly to adhere to intervention methods such as diet control and fitness, the present invention provides Lactococcus lactis subsp. JYLL-51 for improving sarcopenic obesity, its bacterial agent and application.

[0005] First, the present invention provides a Lactococcus lactis subsp. Lactococcus lactis subsp. lactis JYLL-51 for improving sarcopenic obesity, which was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on March 13, 2024. The deposit address is No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC NO. 30016.

[0006] Second, the present invention provides a bacterial agent of Lactococcus lactis subsp. JYLL-51, comprising the above-mentioned Lactococcus lactis subsp. JYLL-51.

[0007] Furthermore, Lactococcus lactis subsp. lactis JYLL-51 was inoculated into MRS liquid medium, and the cells were collected by centrifugation, washed, and then resuspended in reconstituted skim milk. After freeze-drying, it was mixed with isomaltooligosaccharide to obtain the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent; the number of cells in the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent was 1.0×10 10 -1.5×10 10 cfu / g.

[0008] In a third aspect, the present invention provides an application of the above-mentioned Lactococcus lactis subsp. lactis JYLL-51 or the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent in the preparation of a medicament for improving sarcopenic obesity.

[0009] Furthermore, improving sarcopenic obesity includes the simultaneous regulation of body fat and skeletal muscle.

[0010] Furthermore, regulating body fat is to inhibit the increase in the weights of subcutaneous fat, epididymal fat, and perirenal adipose tissue.

[0011] Furthermore, regulating skeletal muscle includes increasing the muscle strength and muscle weight of skeletal muscle.

[0012] Furthermore, increasing the muscle strength of skeletal muscle is to increase the grip strength, and increasing the muscle weight of skeletal muscle is to increase the weights of the gastrocnemius and tibialis anterior muscles.

[0013] Furthermore, skeletal muscle is regulated by inhibiting skeletal muscle protein degradation and promoting skeletal muscle protein synthesis.

[0014] Furthermore, inhibiting skeletal muscle protein degradation includes reducing the protein expression levels of FoxO3a, atrogin-1, and MuRF1 in the gastrocnemius muscle, and promoting skeletal muscle protein synthesis includes upregulating the protein expression levels of p-mTOR and p-S6K in the gastrocnemius muscle.

[0015] The beneficial effects of the present invention are as follows:

[0016] The present invention provides a Lactococcus lactis subsp. lactis JYLL-51 for improving sarcopenic obesity. The strain can be prepared into a Lactococcus lactis subsp. lactis JYLL-51 bacterial agent to improve sarcopenic obesity. Experiments have shown that during or after the establishment of a sarcopenic obesity model, gavage with a certain amount of the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent can not only increase the skeletal muscle weight and strength of aged rats, but also reduce the fat accumulation induced by high fat, and can significantly improve sarcopenic obesity. In particular, for the sarcopenia in sarcopenic obesity, Lactococcus lactis subsp. lactis JYLL-51 can effectively inhibit the increase in skeletal muscle protein degradation and the decrease in skeletal muscle protein synthesis in aged rats caused by high fat by regulating the expression levels of key factors related to skeletal muscle proteins. Brief Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is the effect of Lactococcus lactis subsp. lactis JYLL-51 on the grasping force of aged rats.

[0019] Figure 2 It is the effect of Lactococcus lactis subsp. lactis JYLL-51 on the weight of adipose tissue in aged rats.

[0020] Figure 3 It is the effect of Lactococcus lactis subsp. lactis JYLL-51 on the weights of the gastrocnemius and tibialis anterior muscles.

[0021] Figure 4 It is the effect of Lactococcus lactis subsp. lactis JYLL-51 on the relative weights of the gastrocnemius and tibialis anterior muscles.

[0022] Figure 5 It is the effect of Lactococcus lactis subsp. lactis JYLL-51 on the expression levels of proteins related to protein metabolism in the gastrocnemius muscle. Detailed Embodiments

[0023] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] Example 1 Isolation of Bacterial Strains

[0025] 1. Sampling: Chili peppers, collected from a chili pepper shed in Gaoliu Town, Weifang City, Shandong Province, China in April 2023.

[0026] 2. Isolation of bacterial strains:

[0027] (1) Add the sample collected in step 1 to a sterile Erlenmeyer flask containing sterilized normal saline (0.85%), and obtain a mixed solution after oscillation for later use;

[0028] (2) Dilute the mixed solution to prepare sample solutions with different concentration gradients, which are 10 -1 、10-2 , 10 -3 , 10 -4 , 10 -5 , 10 -6 , 10 -7 , reserved;

[0029] (3)Preparation of MRS plate medium:

[0030] The composition and preparation method of MRS plate medium are as follows:

[0031] Peptone 10g, beef powder 5g, sodium acetate trihydrate 5g, dipotassium hydrogen phosphate heptahydrate 2g, Tween 80 1mL, manganese sulfate tetrahydrate 0.05g, ammonium citrate 2g, glucose 20g, magnesium sulfate heptahydrate 0.2g, agar 15g, distilled water 1000mL;

[0032] Mix the above culture medium raw materials, adjust the natural pH, mix well, sterilize at 121°C and 0.1 MPa for 20 min, pour the sterilized culture medium into petri dishes, and let it cool for later use;

[0033] (4)Cultivation: Spread the sample solutions with different concentration gradients in step (2) on the MRS plate medium in step (3) using a spreader, and cultivate at 37°C under anaerobic conditions for 48 h;

[0034] (5)Select colonies: Select colonies with the characteristics of white, round, moist surface, opaque, and neat edges.

[0035] (6)Isolation and purification

[0036] Pick 5 single colonies according to the colony characteristics in step (5), inoculate them onto the MRS plate medium in step (3) by the streaking method, cultivate at 37°C under anaerobic conditions for 48 h, then pick single colonies and store them in glycerol tubes at -70°C.

[0037] Example 2 Identification and preservation

[0038] Send the strain isolated in Example 1 for identification. The identification unit is Sangon Biotech (Shanghai) Co., Ltd. During the identification process, the following primers are used:

[0039] Primer sequence:

[0040] 27F: AGAGTTTGATCMTGGCTCAG;

[0041] 1492R: GGTTACCTTGTTACGACTT.

[0042] This strain is identified as Lactococcus lactis subsp. lactis (Lactococcus lactis subsp. lactis).

[0043] The gene sequence of this Lactococcus lactis subsp. lactis ( Lactococcus lactis subsp. lactis ) is as follows:

[0044]

[0045] The identified strain was named Lactococcus lactis subsp. lactis JYLL-51 and was sent to the General Microbiology Center of the China General Microbiological Culture Collection Center for preservation. The preservation information is as follows:

[0046] This Lactococcus lactis subsp. lactis ( Lactococcus lactis subsp. lactis ), JYLL-51, was preserved in the General Microbiology Center of the China General Microbiological Culture Collection Center on March 13, 2024. Address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Zip Code: 100101, Preservation Number: CGMCC NO. 30016.

[0047] Example 3 Preparation of Lactococcus lactis subsp. lactis JYLL-51 Bacterial Agent

[0048] First, prepare MRS liquid medium. The composition and preparation method of MRS liquid medium are as follows:

[0049] Peptone 10g, beef powder 5g, sodium acetate trihydrate 5g, dipotassium hydrogen phosphate heptahydrate 2g, Tween 80 1mL, manganese sulfate tetrahydrate 0.05g, ammonium citrate 2g, glucose 20g, magnesium sulfate heptahydrate 0.2g, distilled water 1000mL; Mix the above components, adjust the pH to 6.8, mix well and sterilize at 121°C and 0.1 MPa for 20 min for later use.

[0050] Then, take the preserved Lactococcus lactis subsp. lactis JYLL-51 and activate it on MRS plate medium (the preparation method is the same as step (3) of Example 1). Inoculate the activated bacteria into MRS liquid medium at an inoculation amount of 1%, and culture at 37°C for 24 h to obtain a bacterial liquid.

[0051] Then, centrifuge the bacterial liquid, collect the bacterial cells, wash them with sterile physiological saline, and resuspend them in 15% (w / w) reconstituted skim milk to obtain a suspension; Adjust the concentration of the suspension to 1.8 - 2.0×10 10 cfu / mL to obtain a bacterial suspension. After freeze-drying the bacterial suspension, obtain a bacterial powder.

[0052] Finally, mix the bacterial powder with isomaltooligosaccharide (Baolingbao Biology Co., Ltd.) to make Lactococcus lactis subsp. lactis JYLL-51 bacterial agent. After detection, the number of bacterial cells in Lactococcus lactis subsp. lactis JYLL-51 bacterial agent is 1.0×10 10 cfu / g.

[0053] Example 4 Preparation of Lactococcus lactis subsp. lactis JYLL-51 Bacterial Agent

[0054] The difference from Example 3 is that the number of cells in the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent prepared by mixing the bacterial powder with isomaltooligosaccharide is 1.5×10 10 cfu / g.

[0055] Experimental Example 1

[0056] (1) Grouping and administration

[0057] Twenty-month-old male SPF-grade SD old rats (Chengdu Dashuo Animal Experiment Co., Ltd.) were raised at a room temperature of 22°C, with 12 hours of light and 12 hours of darkness, and free access to food and water. After one week of adaptive feeding, 40 old rats were randomly selected and randomly divided into the following four groups:

[0058] Blank group: Fed with normal feed for 20 weeks and gavaged with normal saline every day.

[0059] Model control group: Fed with high-fat feed for 20 weeks and gavaged with 0.2 mL of normal saline every day.

[0060] JYLL-51 Intervention Group 1: Fed with high-fat feed for 20 weeks. Starting from the 10th week, 0.2 mL of the solution prepared from the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent of Example 3 was gavaged every day (10 mg of the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent of Example 3 was dissolved in 1 mL of normal saline, and the number of cells in the solution was 1×10 8 cfu / mL).

[0061] JYLL-51 Intervention Group 2: Fed with high-fat feed for 20 weeks. Starting from the first day of feeding, 0.2 mL of the solution prepared from the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent of Example 3 was gavaged every day (10 mg of the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent of Example 3 was dissolved in 1 mL of normal saline, and the number of cells in the solution was 1×10 8 cfu / mL).

[0062] (2) Muscle strength test

[0063] Muscle strength test is an important method for evaluating skeletal muscle function. The four groups of old rats were subjected to muscle strength tests.

[0064] Two days before the end of the experimental period (the fifth day of the 20th week of high-fat feed feeding), a grip strength tester (Jiangsu Sians Biotechnology Co., Ltd.) was used to test the grasping strength of old rats. The old rats were placed on the sensing crossbar of the grip meter. After the old rats grasped the crossbar, their tails were dragged horizontally backward until their limbs loosened. The measurement was repeated 3 times and the average value was taken.

[0065] The data was analyzed by one-way ANOVA using SPSS 19.0 software. Tukey-Kramer method was used for pairwise comparison between groups. The data was expressed as mean±SD, and statistical significance was considered when p < 0.05.

[0066] It can be seen from Figure 1 that compared with the blank group, the grasping force (grip strength) of the old rats in the model control group decreased (P < 0.05), indicating that the sarcopenia model was successfully established. Compared with the model control group, the grasping force of the old rats in JYLL-51 intervention group 1 and JYLL-51 intervention group 2 increased accordingly, indicating that the Lactococcus lactis subsp. JYLL-51 preparation could effectively improve the grasping force of the old rats (P < 0.05) and enhance the muscle strength of the old rats.

[0067] (3) Body fat regulation

[0068] One day before the end of the experiment (the sixth day of the 20th week of high-fat diet feeding), the body composition of the old rats was analyzed by small animal CT (Perkin Elemer), and the body fat of the old rats was quantitatively analyzed using analyze 12.0 software.

[0069] The data was analyzed by one-way ANOVA using SPSS 19.0 software. Tukey-Kramer method was used for pairwise comparison between groups. The data was expressed as mean±SD, and statistical significance was considered when p < 0.05.

[0070] It can be seen from Figure 2 that due to the 20-week feeding of high-fat diet, the weights of subcutaneous fat, epididymal fat and perirenal adipose tissue of the old rats in the model control group showed a significant increase (P < 0.05), indicating that the obesity model was successfully established. Compared with the model control group, both JYLL-51 intervention group 1 and JYLL-51 intervention group 2 could significantly inhibit the increase in the weights of subcutaneous fat, epididymal fat and perirenal adipose tissue (P < 0.05). The above results indicate that the Lactococcus lactis subsp. JYLL-51 preparation can reduce the fat accumulation in high-fat-induced old rats and achieve the regulation of body fat.

[0071] In conclusion, the Lactococcus lactis subsp. JYLL-51 preparation can not only effectively improve the grasping force but also achieve the control of body fat, indicating that the intervention of Lactococcus lactis subsp. JYLL-51 can significantly improve sarcopenic obesity.

[0072] Experimental example 2

[0073] To further study the effect of Lactococcus lactis subsp. lactis JYLL-51 on skeletal muscle weight, during the experiment, the body weights of the aged rats in Experimental Example 1 were measured and recorded on a fixed day every week for a total of 20 times. On the last day of the 20th week, the aged rats in each group were sacrificed by cervical dislocation, and the gastrocnemius muscle and tibialis anterior muscle were taken out for weighing. At the same time, 1 g of gastrocnemius muscle tissue was cut and frozen at -80 °C.

[0074] The data were analyzed by one-way ANOVA using SPSS 19.0 software, and pairwise comparisons between groups were performed using the Tukey-Kramer method. The data were expressed as mean ± SD, and a statistically significant difference was indicated when p < 0.05.

[0075] From Figure 3 and Figure 4 it can be seen that compared with the model control group, the weights of the gastrocnemius muscle and tibialis anterior muscle of the aged rats in the JYLL-51 intervention group 1 and JYLL-51 intervention group 2 were increased, and the changes in the relative weights of the gastrocnemius muscle and tibialis anterior muscle (muscle weight / body weight) were consistent with this, indicating that the intervention with Lactococcus lactis subsp. lactis JYLL-51 could significantly inhibit the decrease in skeletal muscle weight caused by high fat, and further indicating that Lactococcus lactis subsp. lactis JYLL-51 could effectively improve the muscle weight loss caused by sarcopenic obesity.

[0076] Experimental Example 3

[0077] When the synthesis rate of skeletal muscle protein exceeds the degradation rate, muscle atrophy will be improved. Therefore, we detected the expression levels of key factors related to protein synthesis and degradation in the skeletal muscle of the gastrocnemius muscle tissue of the four groups of aged rats frozen in Experimental Example 2 by Western blotting to study the effect of Lactococcus lactis subsp. lactis JYLL-51 on the expression levels of proteins related to gastrocnemius muscle protein metabolism.

[0078] Extraction of total protein from samples: Take 50 mg of frozen gastrocnemius muscle tissue and put it into a 2 mL transparent EP tube, add 500 μL of RIPA lysis buffer (strong), 10 μL of phenylmethylsulfonyl fluoride (PMSF), and 10 μL of phosphatase inhibitor. Put the EP tube into a tissue homogenizer for homogenization, then put the homogenized tissue turbid liquid into an ice-water mixture for ultrasonic treatment. After the ultrasonic treatment, let it stand at 4 °C for 30 min, and finally centrifuge at 12,000 g for 10 min at 4 °C. Take the supernatant and transfer it to another prepared EP tube for waiting to measure the protein concentration.

[0079] Determination of protein concentration by BCA method: Dilute the protein standard to a concentration of 0.5 mg / mL, and then add 0 μL, 1 μL, 2 μL, 4 μL, 8 μL, 12 μL, 16 μL, 20 μL into a 96-well plate. Make up to 20 μL with PBS if less than 20 μL; Dilute each group of samples 20 times with PBS, then take 20 μL and add it into a 96-well plate. Add 200 μL of BCA working solution to each well, incubate at 37 °C for 30 min. After the color turns blue-violet, measure the absorbance with an enzyme-linked immunosorbent assay (ELISA) reader. Calculate the protein concentration of each group of samples according to the standard curve and dilution factor, and adjust the four groups of protein samples to the same concentration. Mix the protein samples with SDS-PAGE protein loading buffer at a volume ratio of 4:1, mix well, denature at 100 °C for 10 min, cool to room temperature, aliquot, and store at -20 °C for further use.

[0080] SDS-PAGE gel electrophoresis: Prepare the gel. Prepare separating gels with different concentrations according to the molecular weight of the protein to be detected. The stacking gel is 5%. Immediately start pouring the prepared separating gel after mixing well, and add an appropriate amount of ethanol to seal the gel after completion; After the separating gel solidifies, pour off the ethanol. Add the prepared stacking gel on top of the separating gel, carefully insert the sample comb, and wait for the stacking gel to solidify.

[0081] Loading and electrophoresis: Use a micropipette to add an equal amount of protein sample into the sample wells of the stacking gel, and add a prestained protein Marker into the sample wells on both sides of the sample. After electrophoresis at 80 V for about 50 min, switch to a constant voltage of 180 V and continue electrophoresis. Stop electrophoresis when the bromophenol blue reaches the bottom edge of the gel.

[0082] Transfer: Use the semi-dry method for transfer. First, soak the cut PVDF membrane in anhydrous methanol for 5 min, soak qualitative filter paper in 1× transfer buffer for 10 min in advance, and then place the filter paper, PVDF membrane, and gel in the Semidry transfer apparatus in the following order: Squeeze out as much transfer buffer as possible from the bottom three layers of filter paper and lay it on the bottom layer → PVDF membrane → gel → two layers of filter paper; Flatten with a roller throughout the process to avoid air bubbles, and finally connect the power supply and transfer at a constant voltage of 20 V for 30 min.

[0083] Blocking and antibody incubation: After the transfer is completed, place the PVDF membrane in the pre-prepared 5% skim milk and block it on a shaker at room temperature for 2 h. Take out the PVDF membrane from the blocking solution (5% skim milk), rinse it in TBST, put it into the appropriately diluted primary antibody, and incubate it on a shaker at 4 °C overnight; Recover the primary antibody, wash the membrane on a shaker with TBST for 5 min × 4 times; Add the diluted secondary antibody, incubate it on a shaker at room temperature for 2 h, recover the secondary antibody, and then wash it with TBST for 5 min × 3 times.

[0084] Development, exposure, and protein expression analysis: The strip was placed on the shadow box, and the ECL chemiluminescent substrate (from Immobilon) was evenly added dropwise, followed by exposing the film in a darkroom. The film was developed with a developer and fixed with a fixer in sequence. The gray values presented on the film were analyzed and processed using ImageJ and PS software, and the relative expression level of the target protein was calculated based on the gray value.

[0085] SPSS 19.0 software was used for one-way ANOVA of the data. Tukey-Kramer method was used for pairwise comparison between groups. The data was expressed as mean ± SD. When p < 0.05, the result was considered statistically significant.

[0086] As Figure 5 shown, the intervention of Lactococcus lactis subsp. JYLL-51 could significantly reduce the protein expression levels of FoxO3a, atrogin-1, and MuRF1 in the gastrocnemius muscle of aged rats, decrease the skeletal muscle protein degradation in aged rats caused by high fat, and at the same time up-regulate the protein expression levels of p-mTOR and p-S6K, promoting skeletal muscle protein synthesis in aged rats. In conclusion, the intervention of Lactococcus lactis subsp. JYLL-51 could effectively inhibit the increase in skeletal muscle protein degradation and the weakening of skeletal muscle protein synthesis in aged rats caused by high fat by regulating the expression levels of key factors related to skeletal muscle proteins, indicating that Lactococcus lactis subsp. JYLL-51 could effectively improve sarcopenic obesity.

[0087] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should all be within the scope of the present invention. / Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention.

Claims

1. A Lactococcus lactis subsp. lactis JYLL-51 for improving sarcopenia obesity, characterized in that: Lactococcus lactis subsp. lactis ( Lactococcus lactis subsp. lactis ) JYLL-51 was deposited in the General Microbiology Center of China Microbiological Culture Collection Administration on March 13, 2024. The deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC NO.30016.

2. A Lactococcus lactis subspecies JYLL-51 bacterial agent, characterized in that: The method comprises the Lactococcus lactis subspecies JYLL-51 as claimed in claim 1, wherein the Lactococcus lactis subspecies JYLL-51 is inoculated in an MRS liquid culture medium, the cells are collected by centrifugation, washed, resuspended in reconstituted skim milk, freeze-dried, and mixed with oligosaccharide to obtain a Lactococcus lactis subspecies JYLL-51 bacterial agent; the number of cells in the Lactococcus lactis subspecies JYLL-51 bacterial agent is 1.0×10 10 -1.5×10 10 cfu / g.

3. Use of the Lactococcus lactis subsp. lactis JYLL-51 according to claim 1 or the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent according to claim 2 in the preparation of a medicine for improving sarcopenia obesity, characterized in that: Improving sarcopenic obesity involves simultaneous regulation of body fat and skeletal muscle; Regulating body fat means inhibiting the increase in the weight of subcutaneous fat, epididymal fat and perirenal adipose tissue; regulating skeletal muscle includes improving skeletal muscle strength and muscle weight; improving skeletal muscle strength means improving grip strength, and improving skeletal muscle weight means increasing the weight of the gastrocnemius and tibialis anterior muscles; skeletal muscle is regulated by inhibiting skeletal muscle protein degradation and promoting skeletal muscle protein synthesis.

4. The use according to claim 3, characterized in that Inhibition of skeletal muscle protein degradation included reducing the protein expression levels of FoxO3a, atrogin-1 and MuRF1 in the gastrocnemius muscle, and promotion of skeletal muscle protein synthesis included upregulating the protein expression levels of p-mTOR and p-S6K in the gastrocnemius muscle.

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