Calpains and calpastatin can degrade muscle proteins, but no research has investigated the expression pattern of calpains and calpastatin after exhaustive exercise.
To investigate the alterations in expression of μ-, m-, and n-calpain and calpastatin after exhaustive exercise and its association with muscle injury.
64 rats divided into 2 groups, a nonexercise control group and an acute-exhaustive-exercise (AEE) group. Biopsies in the AEE group were taken at different times after exercise.
Calpastatin protein expression and m-calpain activity increased early after exercise, but both n-calpain protein expression and μ-calpain activity generally decreased with time. n-Calpain mRNA expression was down- regulated from late after exercise.
The increased m-calpain activity might promote muscle-protein degradation and muscle injury. On the contrary, calpastatin might execute a protective function against muscle injury. The change in p-calpain activity was found earlier than muscle injury and therefore might serve as a useful predictor of muscle injury.