Effect of hypoxia combined with exercise training on mitochondrial con-tent in skeletal muscle of rats / 中国病理生理杂志

ABSTRACT

[ABSTRACT]AIM:Toinvestigatetheeffectofhypoxiacombinedwithexercisetrainingonmitochondrialcon-tent, and the role of mitochondrial biogenesis and mitophagy in this process .METHODS:Male Sprague-Dawley rats were randomly divided into 4 groupsnormoxia control (NC) group, normoxia+training (NT) group, hypoxia+control (HC) group, and hypoxia+training (HT) group.The hypoxic animals were housed in normobaric hypoxic tent (11.3 % oxy-gen) for consecutive 4 weeks.The exercise training animals were exercised on a motor-driven rodent treadmill (5°) at a speed of 15 m/min, 60 min/d, 5 d/week for 4 weeks.Mitochondrial membrane potential was determined using JC-1 fluo-rescent probe .ATP synthesis capacity was determined using a bioluminescence technique .The protein expression of cyto-chrome C oxidase IV (COXIV), voltage-dependent anion channel-1 (VDAC-1), peroxisome proliferator-activated receptor gamma cofactor 1 alpha (PGC-1α), mitochondrial transcription factor A (Tfam),Bcl-2/adenovirus E1B 19 kD-interacting protein 3 (Bnip3) and beclin-1 in the muscles was detected by Western blotting .RESULTS:Compared with NC group, hypoxia attenuated mitochondrial membrane potential , ATP synthesis capacity , and the expression of COXIV , VDAC-1, PGC-1αand Tfam.Furthermore, hypoxia increased the expression of Bnip 3 and beclin-1.Compared with HC group , the exercise training elevated mitochondrial membrane potential , ATP synthesis capacity , and the expression of COXIV , VDAC-1, PGC-1α, Tfam, Bnip3 and beclin-1.CONCLUSION:A combination of reduced mitochondrial biogenesis and increased mitophagy seems to be responsible for the decrease in mitochondrial content after hypoxia .Exercise training with hypoxia elevates mitochondrial content and function in hypoxia , which may be mediated by appropriate increase and co-reg-ulation of mitochondrial biogenesis and mitophagy .