Lactococcus lactis subsp. Lactis JYLL-51 for improving sarcopenia obesity as well as fungicide and application of lactococcus lactis subsp. Lactis JYLL-51

Abstract

The invention relates to the technical field of microorganisms, in particular to lactococcus lactis subsp. Lactis JYLL-51 for improving sarcopenia obesity as well as a microbial agent and application of the lactococcus lactis subsp. Lactis JYLL-51. The Lactococcus lactis subsp. Lactis JYLL-51 is preserved in China General Microbiological Culture Collection Center (CGMCC) on March 13, 2024, the preservation address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the preservation number is CGMCC NO.30016. The Lactococcus lactis subsp. Lactis JYLL-51 has the advantages that the Lactococcus lactis subsp. Lactis JYLL-51 can be used for preparing the Lactococcus lactis subsp. Lactis JYLL-51; the invention provides a lactococcus lactis subsp. Lactis JYLL-51, and experiments show that the lactococcus lactis subsp. Lactis JYLL-51 microbial inoculum prepared from the strain can not only improve the weight and strength of skeletal muscle, but also reduce fat accumulation induced by high fat, and can significantly improve sarcopenia obesity.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, and in particular to Lactococcus lactis subspecies JYLL-51 for improving sarcopenia obesity, a bacterial agent and an application thereof. Background Art

[0002] Sarcopenic obesity (SO) is an age-related disease in which obesity and sarcopenia coexist. Sarcopenia is a geriatric syndrome characterized by age-related loss of muscle mass, decreased muscle strength and / or decreased physical function, while obesity is abnormal or excessive fat accumulation that may impair health. Sarcopenic obesity can lead to falls, unsteady walking, balance disorders, and fractures in the elderly, increasing all-cause mortality and social medical burden. Its pathogenesis is relatively complex, and current studies believe that it is closely related to aging, unhealthy lifestyles, and eating habits.

[0003] At present, the commonly used method to improve sarcopenic obesity is to intervene in the lifestyle of the elderly. On the one hand, fat loss and muscle gain can be achieved by limiting energy intake and supplementing sufficient protein. Each meal should contain at least 25 to 30g of protein, taking into account both quantity and weight to stimulate muscle protein synthesis. During the fat loss process, ensure adequate intake of vitamins and minerals to avoid malnutrition. On the other hand, muscle mass and strength can be effectively maintained and visceral fat can be reduced through reasonable exercise. On the premise of ensuring safety, the elderly can perform 150 minutes of moderate-intensity exercise per week. But the reality is that due to the limitations of economic level, ideology, physical condition and other conditions, it is difficult for most elderly people to maintain healthy eating habits and fitness habits for a long time. The elderly population is still a high-risk group for sarcopenic obesity. Summary of the invention

[0004] In view of the technical problem that sarcopenia obesity is common in the elderly, but it is difficult for the elderly to adhere to intervention methods such as controlling diet and fitness, the present invention provides a Lactococcus lactis subspecies JYLL-51 for improving sarcopenia obesity, as well as a bacterial agent and application thereof.

[0005] In a first aspect, the present invention provides a method for improving sarcopenia-related obesity using Lactococcus lactis subsp. 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 No. 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCCNO.30016.

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

[0007] Further, Lactococcus lactis subsp. lactis JYLL-51 was inoculated in MRS liquid culture medium, the cells were collected by centrifugation, washed, and resuspended in reconstituted skim milk, freeze-dried, and mixed with oligosaccharide to obtain a Lactococcus lactis subsp. lactis JYLL-51 inoculum; the number of cells in the Lactococcus lactis subsp. lactis JYLL-51 inoculum was 1.0×10 10 -1.5×10 10 cfu / g.

[0008] In a third aspect, the present invention provides a use 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 medicine for improving sarcopenia obesity.

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

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

[0011] Further, regulating skeletal muscle includes increasing muscle strength and muscle mass of skeletal muscle.

[0012] Furthermore, improving the muscle strength of skeletal muscles means improving grip strength, and improving the muscle weight of skeletal muscles means increasing the weight of 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, the inhibition of skeletal muscle protein degradation included reducing the protein expression levels of FoxO3a, atrogin-1 and MuRF1 in the gastrocnemius muscle, and the promotion of skeletal muscle protein synthesis included upregulating the protein expression levels of p-mTOR and p-S6K in the gastrocnemius muscle.

[0015] The beneficial effects of the present invention are: The present invention provides a Lactococcus lactis subspecies JYLL-51 for improving sarcopenic obesity. The strain is prepared into a Lactococcus lactis subspecies JYLL-51 bacterial agent that can improve sarcopenic obesity. Experiments show that during the modeling of sarcopenic obesity or during the modeling process, gavage of a certain amount of Lactococcus lactis subspecies JYLL-51 bacterial agent can not only improve the skeletal muscle weight and strength of elderly rats, but also reduce the fat accumulation induced by high fat, and can significantly improve sarcopenic obesity. In particular, for the sarcopenic condition of sarcopenic obesity, Lactococcus lactis subspecies JYLL-51 can effectively inhibit the increase in skeletal muscle protein degradation and the weakening of skeletal muscle protein synthesis in elderly rats caused by high fat by regulating the expression level of key factors related to skeletal muscle protein. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 The effect of Lactococcus lactis subsp. lactis JYLL-51 on the grip strength of elderly rats.

[0018] Figure 2 The effect of Lactococcus lactis subsp. lactis JYLL-51 on the adipose tissue weight of aged rats.

[0019] Figure 3 The effect of Lactococcus lactis subsp. lactis JYLL-51 on the weight of gastrocnemius and tibialis anterior muscles.

[0020] Figure 4 The effect of Lactococcus lactis subsp. lactis JYLL-51 on the relative weight of gastrocnemius and tibialis anterior muscles.

[0021] Figure 5 The effect of Lactococcus lactis subspecies JYLL-51 on the expression levels of proteins related to gastrocnemius protein metabolism. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] Example 1 Bacterial strain isolation 1. Sampling: Peppers were collected from the pepper shed in Gaoliu Town, Weifang City, Shandong Province, China in April 2023.

[0024] 2. Isolation of strains: (1) Add the sample collected in step 1 into a sterile Erlenmeyer flask containing sterile saline (0.85%), shake and obtain a mixed solution for later use; (2) The mixed solution was diluted to prepare sample solutions with different concentration gradients, which were 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 , 10-6 , 10 -7 ,spare; (3) Preparation of MRS plate culture medium: The composition and preparation method of MRS plate culture medium are as follows: Peptone 10g, beef powder 5g, sodium acetate trihydrate 5g, potassium hydrogen phosphate heptahydrate 2g, Tween 80 1mL, manganese sulfate tetrahydrate 0.05g, ammonium citrate trihydrate 2g, glucose 20g, magnesium sulfate heptahydrate 0.2g, agar 15g, distilled water 1000mL; The above culture medium raw materials were mixed, the pH was adjusted to natural, and after mixing, they were sterilized at 121°C and 0.1MPa for 20 minutes. The sterilized culture medium was poured into a plate and cooled for later use; (4) Cultivation: Spread the sample solutions of different concentration gradients in step (2) on the MRS plate medium in step (3) using a spreader, and culture at 37° C. under anaerobic conditions for 48 h; (5) Colony selection: Select colonies that are white, round, moist, opaque, and have neat edges.

[0025] (6) Separation and purification According to the characteristics of the colonies in step (5), five single colonies were picked and inoculated onto the MRS plate culture medium in step (3) by streak method. The culture was incubated at 37°C under anaerobic conditions for 48 h. Then, a single colony was picked and placed in a glycerol tube for storage at -70°C.

[0026] Example 2 Identification and preservation The strain isolated in Example 1 was sent for identification by Sangon Biotech (Shanghai) Co., Ltd. During the identification process, the primers used were as follows: Primer sequences: 27F:AGAGTTTGATCMTGGCTCAG; 1492R: GGTTACCTTGTTACGACTT.

[0027] The strain was identified as Lactococcus lactis subsp. lactis (Lactococcus lactis subsp. lactis).

[0028] The Lactococcus lactis subsp. Lactococcus lactis subsp. lactis ) is: The identified strain was named Lactococcus lactis subsp. lactis JYLL-51 and sent to the General Microbiology Center of China Microbiological Culture Collection Administration for preservation. The preservation information is as follows: The Lactococcus lactis subsp. Lactococcus lactis subsp. lactis )JYLL-51, deposited on March 13, 2024 in the General Microbiology Center of China Culture Collection Administration, address: No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Postal Code: 100101, Deposit Number: CGMCC NO.30016.

[0029] Example 3 Preparation of Lactococcus lactis subsp. lactis JYLL-51 bacterial agent First, prepare MRS liquid culture medium. The composition and preparation method of MRS liquid culture medium are as follows: Peptone 10g, beef powder 5g, sodium acetate trihydrate 5g, potassium hydrogen phosphate heptahydrate 2g, Tween 80 1mL, manganese sulfate tetrahydrate 0.05g, triammonium citrate 2g, glucose 20g, magnesium sulfate heptahydrate 0.2g, distilled water 1000mL; mix the above components, adjust the pH to 6.8, mix well, sterilize at 121℃, 0.1MPa for 20min, and set aside.

[0030] The preserved Lactococcus lactis subsp. lactis JYLL-51 was activated on an MRS plate culture medium (the preparation method was the same as step (3) in Example 1), and the activated bacteria were inoculated into an MRS liquid culture medium at an inoculum size of 1%, and cultured at 37° C. for 24 h to obtain a bacterial solution.

[0031] The bacterial solution was then centrifuged, the cells were collected, washed with sterile saline, and resuspended in 15% (w / w) reconstituted skim milk to obtain a suspension; the concentration of the suspension was adjusted to 1.8-2.0×10 10 cfu / mL, a bacterial suspension was obtained, and the bacterial suspension was freeze-dried to obtain bacterial powder.

[0032] Finally, the bacterial powder was mixed with oligomalto-oligosaccharide (Bolling Biotechnology Co., Ltd.) to prepare the Lactococcus lactis subspecies JYLL-51 bacterial agent. The number of cells in the Lactococcus lactis subspecies JYLL-51 bacterial agent was 1.0×10 10 cfu / g.

[0033] Example 4 Preparation of Lactococcus lactis subsp. lactis JYLL-51 bacterial agent The difference from Example 3 is that the number of cells of Lactococcus lactis subsp. lactis JYLL-51 bacterial agent prepared by mixing bacterial powder with oligosaccharide is 1.5×10 10 cfu / g.

[0034] Experimental Example 1 (1) Grouping and dosing 20-month-old male SPF SD rats (Chengdu Dashuo Animal Experiment Co., Ltd.) were raised at 22°C, with 12h light and 12h dark, and free access to food and water. After one week of adaptive feeding, 40 rats were randomly selected and divided into the following four groups: Blank group: The mice were fed with normal diet for 20 weeks and gavaged with normal saline every day.

[0035] Model control group: The mice were fed with high-fat diet for 20 weeks and gavaged with 0.2 mL of normal saline every day.

[0036] JYLL-51 intervention group 1: high-fat diet for 20 weeks, and from the 10th week onwards, 0.2 mL of the solution prepared by the Lactococcus lactis subsp. lactis JYLL-51 agent of Example 3 was gavaged daily (10 mg of the Lactococcus lactis subsp. lactis JYLL-51 agent of Example 3 was dissolved in 1 mL of normal saline, and the number of bacteria in the solution was 1×10 8 cfu / mL).

[0037] JYLL-51 intervention group 2: high-fat diet for 20 weeks, and then gavage 0.2 mL of the solution prepared by the Lactococcus lactis subsp. lactis JYLL-51 agent of Example 3 every day from the beginning of feeding (10 mg of the Lactococcus lactis subsp. lactis JYLL-51 agent of Example 3 was dissolved in 1 mL of normal saline, and the number of bacteria in the solution was 1×10 8 cfu / mL).

[0038] (2) Muscle strength test Muscle strength test is an important method for evaluating skeletal muscle function. Muscle strength test was performed on four groups of elderly rats.

[0039] Two days before the end of the experimental period (the fifth day of the 20th week of high-fat diet feeding), the grip strength tester (Jiangsu Saiangsi Biotechnology Co., Ltd.) was used to test the grip strength of the aged rats. The aged rats were placed on the sensing crossbar of the grip strength meter. After the aged rats grasped the crossbar, they dragged their tails horizontally backward until the limbs of the aged rats were loosened. The measurement was repeated 3 times and the average value was taken.

[0040] SPSS19.0 software was used to perform one-way analysis of variance on the data. The Tukey-Kramer method was used for pairwise comparisons between groups. The data were expressed as mean±SD. When p < 0.05, the results were considered statistically significant.

[0041] Depend on Figure 1It can be seen that compared with the blank group, the grip strength of the model control group decreased (P < 0.05), indicating that the sarcopenia model was successfully established. Compared with the model control group, the grip strength of the elderly rats in the JYLL-51 intervention group 1 and the JYLL-51 intervention group 2 increased accordingly, indicating that the Lactococcus lactis subsp. lactis JYLL-51 bacterial agent can effectively improve the grip strength of elderly rats (P < 0.05) and improve the muscle strength of elderly rats.

[0042] (3) Body fat regulation 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 aged rats was analyzed using a small animal CT (Perkin Elemer), and the body fat of the aged rats was quantitatively analyzed using Analyze 12.0 software.

[0043] SPSS19.0 software was used to perform one-way analysis of variance on the data. The Tukey-Kramer method was used for pairwise comparisons between groups. The data were expressed as mean±SD. When p<0.05, the results were considered statistically significant.

[0044] Depend on Figure 2 It can be seen that the weight of subcutaneous fat, epididymal fat and perirenal fat tissue in the model control group increased significantly due to high-fat diet for 20 weeks (P < 0.05), indicating that the obesity model was successfully established. Compared with the model control group, the increase of subcutaneous fat, epididymal fat and perirenal fat tissue weight in JYLL-51 intervention group 1 and JYLL-51 intervention group 2 was significantly inhibited (P < 0.05). The above results show that the lactococcus lactis subsp. lactis JYLL-51 bacterial agent can reduce the fat accumulation of elderly rats induced by high fat and achieve the regulation of body fat.

[0045] In summary, the Lactococcus lactis subsp. lactis JYLL-51 inoculum can not only effectively improve grip strength, but also control body fat, indicating that Lactococcus lactis subsp. lactis JYLL-51 intervention can significantly improve sarcopenia-induced obesity.

[0046] Experimental Example 2 In order to further study the effect of Lactococcus lactis subsp. lactis JYLL-51 on skeletal muscle weight, the body weight of the middle-aged and elderly rats in Experimental Example 1 was measured and recorded on a fixed day per week during the experiment, and the body weight was measured 20 times in total. On the last day of the 20th week, the elderly rats in each group were killed by cervical dislocation, and the gastrocnemius and tibialis anterior muscles were taken out for weighing. At the same time, 1g of gastrocnemius muscle tissue was cut and frozen at -80°C.

[0047] SPSS19.0 software was used to perform one-way analysis of variance on the data. The Tukey-Kramer method was used for pairwise comparisons between groups. The data were expressed as mean±SD. When p<0.05, the results were considered statistically significant.

[0048] Depend on Figure 3 and Figure 4 It can be seen that compared with the model control group, the weight of the gastrocnemius and tibialis anterior muscles of the elderly rats in the JYLL-51 intervention group 1 and JYLL-51 intervention group 2 were increased, and the changes in the relative weight of the gastrocnemius and tibialis anterior muscles (muscle weight / body weight) were consistent with this, indicating that the intervention with Lactococcus lactis subsp. lactis JYLL-51 can significantly inhibit the decrease in skeletal muscle weight caused by high fat, and further shows that Lactococcus lactis subsp. lactis JYLL-51 can effectively improve the loss of muscle weight caused by sarcopenia obesity.

[0049] Experimental Example 3 When the synthesis rate of skeletal muscle protein exceeds the degradation rate, muscle atrophy will be improved. Therefore, we used Western blotting to detect the expression levels of key factors related to protein synthesis and degradation in skeletal muscle of the gastrocnemius muscle tissues of the four groups of aged rats frozen in Experimental Example 2, and studied the effect of Lactococcus lactis subsp. lactis JYLL-51 on the expression levels of proteins related to gastrocnemius protein metabolism.

[0050] Extract 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 RIPA lysis buffer (strong), 10 μL phenylmethylsulfonyl fluoride (PMSF) and 10 μL phosphatase inhibitor, put the EP tube into a tissue homogenizer for homogenization, and then put the homogenized tissue turbidity into an ice-water mixture for ultrasonication. After the ultrasonication, let it stand at 4°C for 30 minutes, and finally centrifuge it at 12000g for 10 minutes at 4°C. Take the supernatant and transfer it to another prepared EP tube for protein concentration determination.

[0051] BCA method to determine protein concentration: dilute the protein standard to 0.5 mg / mL, then add 0 μL, 1 μL, 2 μL, 4 μL, 8 μL, 12 μL, 16 μL, and 20 μL to a 96-well plate. If the sample is less than 20 μL, add 20 μL to the 96-well plate with PBS; dilute each sample 20 times with PBS and add 20 μL to each well, then add 200 μL of BCA working solution to each well, incubate at 37°C for 30 minutes, and place the sample in a microplate reader to detect absorbance after the color changes to blue-purple. Calculate the protein concentration of each sample according to the standard curve and the dilution multiple, 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, denature at 100°C for 10 minutes, return to room temperature, and then pack and store at -20°C for testing.

[0052] SDS-PAGE gel electrophoresis: gel preparation, according to the molecular weight of the protein to be tested, prepare different concentrations of separation gel, the concentration gel is 5%, mix the prepared separation gel and start injecting the gel immediately, add an appropriate amount of ethanol to seal the gel after completion; after the separation gel solidifies, pour out the ethanol. Add the prepared concentration gel on the separation gel, carefully insert the sample comb, and wait for the concentration gel to solidify.

[0053] Sample loading and electrophoresis: Use a micropipette to add an equal amount of protein sample to the sample well of the concentrated gel, and add pre-stained protein markers to the sample wells on both sides of the sample. After electrophoresis at 80V for about 50 minutes, switch to 180V constant voltage to continue electrophoresis. Stop electrophoresis when bromophenol blue reaches the bottom edge of the gel.

[0054] Transfer: Use the semi-dry method for transfer. First, soak the cut PVDF membrane in anhydrous methanol for 5 minutes. Soak the qualitative filter paper in 1× transfer solution for 10 minutes in advance. Then put the filter paper, PVDF membrane and gel into the Semidry transfer instrument in order. The order is as follows: squeeze the transfer solution as much as possible on the three layers of filter paper below and lay them on the bottom layer → PVDF membrane → gel → two layers of filter paper; use a roller to flatten the whole process to avoid bubbles. Finally, turn on the power and transfer the membrane at 20V constant voltage for 30 minutes.

[0055] Blocking and antibody incubation: After the transfer, place the PVDF membrane in the 5% skim milk prepared in advance and block it on a shaker at room temperature for 2 hours. Take out the PVDF membrane from the blocking solution (5% skim milk), rinse it in TBST, add the corresponding diluted primary antibody, and incubate it on a shaker at 4°C overnight; recover the primary antibody, and wash the membrane with TBST for 5 minutes × 4 times; add the diluted secondary antibody, incubate it on a shaker at room temperature for 2 hours, recover the secondary antibody, and then wash it with TBST for 5 minutes × 3 times.

[0056] Development, exposure and protein expression analysis: Spread the strips on the shadow box, evenly add ECL luminescent substrate (Immobilon) and expose the film in a dark room. The film is developed with developer and fixed with fixer. ImageJ and PS software are used to analyze and process the grayscale values ​​on the film, and the relative expression of the target protein is calculated based on the grayscale value.

[0057] SPSS19.0 software was used to perform one-way analysis of variance on the data. The Tukey-Kramer method was used for pairwise comparisons between groups. The data were expressed as mean±SD. When p<0.05, the results were considered statistically significant.

[0058] like Figure 5As shown in the results, Lactococcus lactis subsp. lactis JYLL-51 intervention can significantly reduce the expression levels of FoxO3a, atrogin-1 and MuRF1 proteins in the gastrocnemius of aged rats, reduce the skeletal muscle protein degradation caused by high fat in aged rats, and upregulate the expression levels of p-mTOR and p-S6K proteins, promoting skeletal muscle protein synthesis in aged rats. In conclusion, Lactococcus lactis subsp. lactis JYLL-51 intervention can effectively inhibit the increase of 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 protein, indicating that Lactococcus lactis subsp. lactis JYLL-51 can effectively improve sarcopenia-induced obesity.

[0059] Although the present invention has been described in detail with reference 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, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection 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: Including the Lactococcus lactis subspecies JYLL-51 as described in claim 1.

3. A Lactococcus lactis subspecies JYLL-51 bacterial agent as claimed in claim 2, characterized in that: Lactococcus lactis subsp. lactis JYLL-51 was inoculated in MRS liquid medium, the cells were collected by centrifugation, washed, and resuspended in reconstituted skim milk. After freeze-drying, it was mixed with oligosaccharide to obtain the Lactococcus lactis subsp. lactis JYLL-51 inoculum. The number of cells in the Lactococcus lactis subsp. lactis JYLL-51 inoculum was 1.0×10 10 -1.5×10 10 cfu / g.

4. 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.

5. The use according to claim 4, characterized in that Improving sarcopenic obesity involves simultaneous regulation of body fat and skeletal muscle.

6. The use according to claim 5, characterized in that Regulating body fat means inhibiting the increase in the weight of subcutaneous fat, epididymal fat and perirenal adipose tissue.

7. The use according to claim 5, characterized in that Modulating skeletal muscle includes increasing the muscle strength and muscle mass of skeletal muscle.

8. The use according to claim 7, characterized in that Improving skeletal muscle strength means improving grip strength, and increasing skeletal muscle weight means increasing the weight of the gastrocnemius and tibialis anterior muscles.

9. The use according to claim 5, characterized in that Regulates skeletal muscle by inhibiting skeletal muscle protein degradation and promoting skeletal muscle protein synthesis.

10. The use according to claim 9, 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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