Previous studies reported inconsistent findings on autophagy activation in skeletal muscles after acute exercise. In this study, we investigated the effect of a single bout of exhaustive treadmill exercise on AMPK and autophagy activations in mice gastrocnemius muscle in vivo. Male ICR/CD-1 mice were randomly divided into the control and exercise groups. The later was subjected to a single bout of exhaustive treadmill exercise. Changes of AMPK, phosphorylation of AMPKThr172 (pAMPKThr172 ), and autophagy markers including Beclin1, LC3II/LC3I and p62 mRNA and protein expressions in gastrocnemius muscle at different times (0, 6, 12, 24 h) after the exercise were analysed by quantitative real-time PCR and western blot. Our results demonstrated that a single bout of exhaustive treadmill exercise significantly induced AMPK content and AMPK activity at 0, 6 and 12 h after the exercise, and changed the expressions of autophagy markers at different time points in the recovery period, respectively. Moreover, we observed positive correlations between expressions of LC3II/LC3I ratio and pAMPKThr172 or AMPK, and a negative correlation between expressions of p62 and AMPK or pAMPKThr172 . In conclusion, a single bout of exhaustive treadmill exercise in mice caused a prolonged activation of AMPK and improved autophagy in the gastrocnemius muscle. The regulation of autophagic markers were related to enhanced AMPK activity. The findings indicate that acute exercise enhanced AMPK-related autophagy activation may be the underlying molecular mechanism that regulates cellular energy metabolism during exercise.
Keywords: AMPK activity; a single bout of exhaustive treadmill exercise; autophagy; skeletal muscle.
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