Objective To observe the effects of exercise combined with probiotic intervention on glycolipid metabolism,oxidative stress,and skeletal muscle satellite cell expression in type 2 diabetic rats.Methods From 60 8-week-old SPF-grade SD male rats,10 rats were randomly selected as the normal control group(NC),and the rest were injected intraperitoneally with streptozotocin,establishing a rat model of type 2 diabetes mellitus.The diabetic rats were randomly divided into model(TN),exercise+diabetes(YTN),probiotic+diabetes(GTN),and exercise+probiotics+diabetes(YGTN)groups.The exercise groups were subjected to 6 weeks of incremental load aerobic treadmill exercise(speed of 15 m/min for 30 min in week 1,15 m/min for 60 min in week 2,and 19.3 m/min for 60 min in weeks 3～6,with continuous training until week 6,5 days/week).The GTN and YGTN groups were administered 10.0 mL/(kg·d)of Lactibiane Iki probiotic solution(concentration of 107 CFU/mL)one hour before training.Glycolipid metabolism indexes,oxidative stress indexes,and expression of skeletal muscle satellite cell proteins were measured in rats.Results(1)The levels of fasting plasma glucose(FBG),fasting serum insulin(FINS),hemoglobin Alc(HBA1C)and(homeostasis model assessment-insulin resistance index(HOMA-1R)were higher in the TN,YTN,GTN,and YGTN groups than in the NC group(P＜0.01).The levels of FBG in the YGTN group were lower than those in the TN,YTN,GTN,and YGTN groups(P＜0.05).Serum FINS levels in YTN,GTN and YGTN groups were all decreased compared with those in the TN group(P＜0.01).Serum HBA1C levels were lower in the YGTN group than the TN,YTN,and GTN groups(P＜0.01).The HOMA-IR indices of rats in the YGTN group decreased more significantly compared with those in the TN,YTN,and GTN groups(P＜0.01).The result showed that FBG,FINS,HBA1C,and HOMA-IR decreased more significantly in rats in the aerobic exercise combined with probiotic intervention group than the other intervention groups.(2)Serum total cholesterol(T-CHO),triglyceride(TG),low density lipoprotein cholesterol(LDL)and free fatty acid(FFA)levels in the TN group were higher than those in the NC group(P＜0.05),and those of the YGTN group were lower than those of the TN group(P＜0.05)and basically restored to the level of the NC group.Serum high density lipoprotein cholesterol(HDL)levels were lower in the TN group than the NC group(P＜0.05),Serum HDL levels of rats in TN group were lower than those of the NC group(P＜0.05),and those in the YGTN group were higher than those of TN group(P＜0.05),which were basically restored to the level of NC group.The result showed that aerobic exercise combined with probiotic intervention reduced serum T-CHO,TG,LDL,FFA levels and increased HDL levels more significantly than other interventions in diabetic rats.(3)Serum malondialdehyde(MDA)and 8-iso-prostaglandin F2α(8-isoPGF2α)levels of rats in the TN group were higher than those in the NC group(P＜0.05 or P＜0.01),and those of rats in the YGTN group were lower than those in the TN group(P＜0.05 or P＜0.01).Serum catalase(CAT),superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)and total antioxidant capacity(T-AOC)in the TN group were lower than those in the NC group(P＜0.01),and those of rats in the YGTN group were higher than those of the NC group(P＜0.01)and were basically restored to the levels of NC group.(4)The protein expression levels of paired box gene 7(Pax7),myogenic determination gene(MyoD),myogenin(MyoG)and myogenic factor 5(Myf5)in the skeletal muscle of rats in the TN group were lower than those in the NC group(P＜0.05 or P＜0.01),and these levels were higher in the YGTN group than the TN group(P＜0.05 or P＜0.01);basically,the levels were restored to those of the NC group.In the TN group,myostatin(MSTN)protein expression was higher in the TN group than the NC group(P＜0.05),and that in the YGTN group was lower than that in the TN group(P＜0.05)and basically restored to the level of the NC group.Conclusions The result showed that probiotics and aerobic exercise had a synergistic effect in improving blood glucose and insulin levels,attenuating insulin resistance,improving lipids and oxidative radicals,and preventing the phenomenon of disturbed glucose metabolism,thus achieving dynamic equilibrium regulation in type 2 diabetic rats.Aerobic exercise combined with probiotics also promoted myoblast differentiation,which played a role in preventing T2DM-induced loss of muscle mass and strength as well as muscle tissue complications.

BACKGROUND:Acute exercise tends to cause skeletal muscle tissue damage and lipid metabolism disorders in vivo,but the mechanism by which acute exercise combined with electroacupuncture modulates metabolic and autophagic pathways in vivo is unclear. OBJECTIVE:To observe the changes in metabolic enzymes and autophagy levels in skeletal muscle of rats subjected to acute exercise by electroacupuncture at the acupoints of"Zusanli"and"Huantiao." METHODS:Fifty male Sprague-Dawley rats were randomly divided into three groups:quiet control group(n=10),model group(n=20),and reverse electroacupuncture group(n=20).The latter two groups were set up with two time points,i.e.immediate and 3 hours after exercise groups(n=10 per time point).The model group and the reverse electroacupuncture group underwent acute exercise training after adaptive treadmill training.The rats in the reverse electroacupuncture group underwent electroacupuncture treatment(parameters:electroacupuncture on both sides of the rats at the acupoints of"Zusanli"and"Huantiao,"continuous wave,frequency of 2 Hz,intensity of 2 mA,leaving the needle in the body for 30 minutes,once a day for 7 consecutive days)before treadmill training.Bilateral gastrocnemius muscle tissues were taken under anesthesia immediately after exercise and 3 hours after exercise,and hematoxylin-eosin staining was used to observe the histopathological changes of rat skeletal muscle.ELISA kit was used to detect the activities of hepatic lipase,fatty acid synthase,hormone-sensitive lipase,and carnitine palmitoyltransferase 1 in rat skeletal muscle tissues.Immunohistochemistry and western blot were used to detect the changes in the expression of autophagy genes. RESULTS AND CONCLUSION:After hematoxylin-eosin staining,the arrangement of gastrocnemius muscle fibers in the model group was disturbed,swollen and ruptured immediately after exercise and 3 hours after exercise.In the reverse electroacupuncture group,gastrocnemius muscle fibers were tightly arranged and the number of swollen and ruptured cells was greatly reduced immediately after exercise and 3 hours after exercise,and there was no significant difference when compared with the quiet control group.Compared with the quiet control group,the activities of hepatic lipase and fatty acid synthase were lower while the activities of lipoprotein lipase,hormone-sensitive lipase,and carnitine palmitoyltransferase 1 were higher in the model group and the reverse electroacupuncture group 3 hours after exercise(P＜0.05 or P＜0.01).Compared with the model group,the activities of lipoprotein lipase and carnitine palmitoyltransferase 1 were higher in the reverse electroacupuncture group immediately after exercise(P＜0.05),while the activity of lipoprotein lipase was higher and the activity of hormone-sensitive lipase was lower in the reverse electroacupuncture group 3 hours after exercise(P＜0.01).Immunohistochemical results showed that compared with the quiet control group,the expression of P62,autophagy-related gene 5 and autophagy-related gene 7 was higher in the model group immediately and 3 hours after exercise,as well as in the reverse electroacupuncture group immediately after exercise(P＜0.05 or P＜0.01);compared with the model group,the expression of P62 and autophagy-related gene 7 was lower in the reverse electroacupuncture group immediately and 3 hours after exercise(P＜0.05).Western blot results showed that the protein expression of P62 and autophagy-related gene 7 in the reverse electroacupuncture group was lower than that in the model group immediately after exercise(P＜0.05);the protein expression of Parkin in the model group was higher than that in the quiet control group immediately and 3 hours after exercise(P＜0.05);and the protein expression of Parkin in the reverse electroacupuncture group was lower than that in the model group immediately and 3 hours after exercise(P＜0.05).To conclude,acute exercise induces disorders,swelling and rupture of gastrocnemius muscle fibers in rats and electroacupuncture on both sides of the acupoints of"Zusanli"and"Huantiao"can improve the level of lipid metabolism and regulate autophagy cells in rat skeletal muscle,preventing the disorders of lipid metabolism and damage of gastrocnemius muscle tissues caused by acute exercise.The mechanism may be closely related to the regulation of autophagy-related factor P62,autophagy-related gene 5,autophagy-related gene 7,and Parkin protein expression to promote the occurrence of autophagy or regulate the autophagy pathway in rat skeletal muscle cells.