Effects Of Swimming On Oxidative Stress And GRP78/CHOP In Skeletal Muscle Of Rats

Objective:To investigate the effects of one-time exhaustive exercise,six-week swimming exercise and one-time exhaustive exercise after six weeks of swimming exercise on oxidative stress and endoplasmic reticulum stress in skeletal muscle of rats.The changes of oxidative stress and endoplasmic reticulum stress in skeletal muscles of rats before and after exercise were compared.To explore the relationship between oxidative stress and endoplasmic reticulum stress in rat skeletal muscles under intervention of three different exercise modes.This study provides a theoretical basis for studying the molecular mechanism of exercise-induced oxidative stress and endoplasmic reticulum stress in skeletal muscle and the study of oxidative stress and endoplasmic reticulum stress-related diseases.Methods:40 SD rats were randomly divided into four groups of 10 in each group:a quiet control group?C?,one-time exhaustive exercise group?L?,6-week swimming group?Y?,and one-time exhaustive exercise group after 6weeks swimming?LY?.The 6-week swim training rats had no weight-bearing free swimming,training 6 times a week?one day off on Sunday?,and each training for 60 minutes.One-time swimming exhaustion criteriarats had no weight-bearing free swimming,swimming to rats sinking into the bottom of the pool,and within 10s does not reveal the surface of the water.The rats were allowed to swim until exhaustion.The rats were immediately decapitated after exercise.Determination of total protein content of soleus muscle by BCA;determination of catalase?CAT?by visible light method;determination of H₂O₂by spectrophotometry;determination of MDA content by TBA;determination of superoxide dismutase?SOD?by WST-1;The protein expression of GRP78 and CHOP in soleus muscle was determined by blotting.Result:The levels of H₂O₂ and MDA in skeletal muscles of rats subjected to one-time exhaustion were significantly higher than those in the quiet group?P<0.05,P<0.01?,while the enzyme activities of SOD and CAT were significantly lower than those in the control group?P<0.05,P<0.01?;There was no significant phase change in skeletal muscle H₂O₂,MDA,SOD,CAT in the6-week swimming group.The H₂O₂ in soleus muscles of rats in one-time exhaustive exerciseafter 6 weeks swimming group was significantly lower than that in the one-time exhaustive exercise group?P<0.05?,and the CAT enzyme activity was significantly lower in the rats than in the control group?P<0.01?,but higher than that in the exhausted group?P<0.05?;The level of GRP78 expression in the one-time exhaustive group was significantly higher than that in the 6-week swimming group?P<0.05?and the quiet group?P<0.05?.The remaining groups were not significantly different.There was no significant difference in the expression of CHOP in the soleus muscle between the groups.Conclusions:1.After exhaustive exercise,the content of H2O2 and MDA in skeletal muscle increased obviously,the activity of SOD and CAT decreased and the expression of GRP78 protein increased,but it did not cause the change of apoptotic protein CHOP.It indicated that exhaustion exercise could improve the oxidative stress level of skeletal muscle in rats and induce the occurrence of endoplasmic reticulum stress,but there was no apoptosis at this time.2.6-week exercise did not cause changes in oxidative stress and endoplasmic reticulum stress related indexes in rat skeletal muscle,indicating that long-term exercise made the oxidative stress level of skeletal muscle in the rat stable,and did not induce endoplasmic reticulum stress.3.6-week exercise decreased the content of skeletal muscle oxide in rats after exhaustive exercise,increased the activity of antioxidant enzymes and decreased the level of endoplasmic reticulum stress,indicating that long-term exercise reduced the level of oxidative stress and the stress level of endoplasmic reticulum after exhaustive exercise,and increased the tolerance of skeletal muscle to exhaustion movement.