Experimental Study Of Gastrodia Elata Polysaccharide On Skeletal Muscle Aging Induced By D-galactose In Mice

Objective:To investigate the delaying effect and mechanism of Gastrodia elata polysaccharide?GEP?on skeletal muscle aging induced by D-galactose in mice.Methods:Fifty three-month-old Kunming mice were randomly divided into five groups?n=10/group,half male and half female?:control group?control?,model group?D-gal?,Gastrodia elata polysaccharide low-dose group(0.4 mg/(g·d^-1)?L?,medium-dose group(2 mg/(g·d^-1)?M?,high-dose group(10 mg/(g·d^-1)?H?.The experimental model was established by subcutaneous injection of 5%D-galactose?125 mg/kg?into the neck and back of mice in three Gastrodia elata polysaccharide dosage groups and model group for 8 weeks.In the meantime the control group was injected with physiological saline of the same volume.Starting from the 8th day of modeling,Gastrodia elata polysaccharides in low,medium and high dose groups were administrated by Gastrodia elata polysaccharides 0.4 mg/(g·d^-1),2 mg/(g·d^-1)and 10mg/(g·d^-1)respectively for 7 weeks.All mice were fed with general feed,free diet and drinking water,and the ambient temperature was maintained between 20 and 24degrees Celsius.The following indexes were observed:?1?the growth status of mice in each group was observed and their weight was measured.?2?the muscle strength of limbs was measured by horizontal rope test.?3?the coefficients of muscle tissue,liver and kidney were measured.?4?the cross-sectional area of muscle fibers was compared with HE staining.?5?the activity of superoxide dismutase?SOD?,glutathione peroxidase?GSH-Px?,catalase?CAT?,the content of malondialdehyde?MDA?and 8-hydroxydeoxyguanosine?8-OHdG?in the skeletal muscle of rat was detected by ELISA.?6?The mRNA expression and protein levels of Caspase-3,MAFbx and MuRF-1 were detected by qRT-PCR and Western blot respectively.Results:?1?Compared with the control group,the model group showed obvious depilation,decreased mobility and weight loss;compared with the model group,GEP improved skeletal muscle aging induced by D-galactose in a time-and dose-dependent manner,increased body weight,maintained the stability of organ coefficient and enhanced muscle strength of mice.?2?Compared with the control group,the cross-sectional area of skeletal muscle fibers in the model group decreased significantly?P<0.05?;compared with the model group,the cross-sectional area of skeletal muscle fibers gradually recovered after GEP intervention,with statistical significance?P<0.05?.?3?The results of ELISA test showed that compared with the control group,SOD,GSH-Px and CAT levels in the model group decreased,while MDA and 8-OHdG contents increased?P<0.05?;however,compared with the model group,SOD,CAT and GSH-Px levels in the skeletal muscle tissue of mice in the GEP group increased,while MDA and 8-OHdG levels decreased significantly?P<0.05?,and the greater the dose of GEP,the more obvious the changes of the above indicators were.?4?RT-PCR and Western blot results showed that compared with the control group,the expression of Caspase-3,MAFbx and MuRF-1 in the model group increased significantly?P<0.05?,and the expression of Caspase-3,MAFbx and MuRF-1 in the GEP group decreased significantly?P<0.05?,and the higher the dose of GEP,the lower the expression of Caspase-3,MAFbx and MuRF-1.Conclusion:GEP delays D-galactose-induced skeletal muscle aging.It may be related to down-regulation of Caspase-3,MAFbx and MuRF-1 expression.