Effects Of 4-week Hypoxic Exercise On The Temporal Changes Of Autophagy-related Factors In Skeletal Muscle Of Obese Rats

1 objective:To investigate the effects on the autophagy-related factors P62,LC3 and Beclin-1 in healthy obese rats under hypoxic exercise circumstances and its potential mechanism of hyPoxia-induced autophagy in skeletal muscle cells.2 Method:Establishing rat models of nutritional obesity by inducing SD rats using high fat diet,the 50 rats models were randomly divided into 5 grou Ps: Control Group(C),1-week hypoxic exercise Group(E1),2-week hypoxic exercise Group(E2),3-week hypoxic exercise Group(E3),4-week hypoxic exercise Group(E4),each group contains 10 rats.HyPoxic exposure simulates 13.6% of oxygen concentration(it's about the actual elevation of 3500-meter oxygen content),trained on the action treadmill,at the speed of 20 m.min-1,the slope is zero,training for 1 hour every day,taking a 2-day break on the weekends,each group is trained separately for 1 week,2 weeks,3 weeks or 4 weeks.At the end of the last training,the animals were sacrificed and sampled,detecting the gastrocnemius muscle P62,LC3 and Beclin-1 mRNA of rat models using RT-PCR and the changes of P62,LC3 and Beclin-1 proteins before and after the experiment using westent blot.3 Results:The expression of Beclin-1 mRNA was significantly increased in E1,E2 and E3 groups compared with grouP C(P <0.05),the expression in E4 was slightly declined,the protein expression of Beclin-1 decreased gradually in the first two weeks,the protein expression of Beclin-1 in E2 was significantly declined compared with group C(P <0.05),it increased gradually in the following two weeks,the protein expression of Beclin-1 in E4 was significantly increased compared with E2(P<0.01);The relative expression of P62 mRNA in group E1 was significantly increased com Pared with group C(P <0.05),the relative expressionof P62 mRNA in E2 was gradually increased compared with E1(P <0.05),the relative expressionof P62 mRNA in E3 was significantly lower than that in E2 and E4(P<0.01).The relative ex Pression of P62 protein in obese rats from E3 group was significantly increased compared with that in E2 group;The relative expression of LC3 mRNA in E2 group,E3 group and E4 group were all higher than that in C group(P<0.05),the changes of LC3 II / LC3 I of LC3 protein in obese rats from the 5 groups were not obvious.4 Conclusions:(1)Hypoxic exercise can significantly increase the relative expression of autophagy genes,to a certain extent,promote the occurrence of autophagy,however,the transcription of autophagy genes and the synthesis of autophagy protein are not synchronized.(2)In the first two weeks of hypoxia training,the degree of autophagy of skeletal muscle tended to increases,but with the extension of stimulation time,the degree of skeletal muscle autophagy gradually reduced,this may result from the gradual adaptation of the body to the stimulation of hypoxia.