ABSTRACT

　The purpose of this study was to examine the effect of mild normobaric hypoxia on the sprint-interval training (SIT)-induced histone deacetylases (HDACs) protein expression and histone modification (acetylation) in the rat gastrocnemius muscle. Male Wistar rats (8weeks old) were assigned randomly into normoxic control (NC), normoxic training (NT), hypoxic control (HC) or hypoxic training (HT) groups (n=6/group). The training group rats were exposed to SIT on a treadmill (1min sprint and 2-5min rest, 6-10sets/day) 5-6 days per week for 9 weeks. After the experiment, the gastrocnemius muscles were removed and the expression of HDACs and the global levels of histone acetylation were determined by Western blot analysis. A two-way ANOVA revealed significant effects of hypoxia on the CS activity; however, no main effect of hypoxia and training was observed in the PGC1-α, SOD1, HIF-1 and VEGF. Although, there was no change in HDAC4 expression, effect of hypoxia on HDAC5 and effect of training on nuclear SIRT1 were observed. There were no significant effect of training on the acetylation of histone H3 among groups. However, de-acetylation of lysine residue 9 and 27 was significantly lower in the Hypoxic groups compared with the NC group. These findings demonstrated that SIT could enhance the improvement of the citrate synthase activity (oxidative capacity) in the gastrocnemius muscle, and it is partly related to the decline of histone acetylation mediated by the alternation of class III histone deacetylase SIRT1 in normobaric hypoxia.

DESCENTE SPORTS SCIENCE Vol.38/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE