Influence Of Hypoxia And Hypoxic Exercise On Dystrophin And Desmin In Rats Skeletal Muscle

Purpose:The present study examined the effects of hypoxia and hypoxic exercise on Dystrophin and Desmin in rats skeletal muscle.Difference between hypoxic and normoxic recovery after EIMD was compared in this present study.Analyze the relationship between serum enzyme CK,LDH increase and EIMD.In order to analysis the mechanism of regulating skeleton protein,the gene expression of skeleton protein,Calpain activity and HSP were measured.Experimental Methods:The investigation involved an acute hypoxia concentric exercise test and an experiment of only hypoxia stress.SD Rats were divided in 8 groups, normoxic rest,and 1d、2d、7d after exercise in normal or 12.7%02 (hypoxia),in the acute hypoxia concentric exercise test.After the exercise of 1×5min×10m/min,4×5min×15m/min and 1×5min×20m/min, which interrupted by 1 minute.There were 5 groups,normal rest and 1d、2d、4d、7d of 10%02(hypoxia),in the experiment of only hypoxia stress. The loss of membrane integrity of 2 rats in each group was showed by injecting EBD.Results:(1)The content of Desmin and Dystrophin were influenced by hypoxia and concentric exercise under hypoxia.The content of Desmin and Dystrophin fluctuated under only hypoxia stress.The results of concentric exercise under hypoxia showed Desmin of muscle tissues have increased,and the rod domain of Dystrophin was destroyed.(2)As same as eccentric exercise, concentric exercise under hypoxia also can induce the membrane integrity damaged just after exercise.These changes were still observed after 7 days of normoxia.The recovery under hypoxia was quicker than under normoxia.Besides mechanical stress,only hypoxia stress also can induce the membrane integrity damaged.(3)There was remarkable relationship between Calpain activity and the extent of membrane integrity damaged, and between Calpain activity and the disruption of Desmin under whether normoxia or hypoxia of 12.7%oxygen.The fibers that EBD stained clearly were typeⅡin concentric exercise under hypoxia,as well as in the experiment of only hypoxia stress.There was no remarkable relationship in time between sarcolemma integrity and serum CK,LDH.(4)The content of HSP90,HSP70 and HSP32 all increased just after concentric exercise under hypoxia.The regulation of HSP was early than the regulation of Desmin gene and Dystrophin gene.Conclusions:The content of Desmin and Dystrophin were influenced by hypoxia and concentric exercise under hypoxia.rhe content of Desmin and Dystrophin maybe regulated by the expression of gene under hypoxia.The expression of gene was the main cause of the rapidly synthesis of Desmin,but Dystrophin synthesized by the regulation after translation of gene(or repairability of protein).The results hold out that degradation of Desmin relate to Calpain.The lose of Dystrophin maybe relate to mechanical stress caused by exercise.There was remarkable relationship between.the loss of membrane integrity was a active physiological reaction.The mechanical stress is not the only cause of the loss of membrane integrity.The results that showed the Dystrophin molecule wasn ’t selectively destroyed in C-terminal domain.