title: Acute-exercise-induced alterations in calpain and calpastatin expression in rat muscle.
abstract: BACKGROUND
  Calpains and calpastatin can degrade muscle proteins, but no research has investigated the expression pattern of calpains and calpastatin after exhaustive exercise.
  
  
  OBJECTIVE
  To investigate the alterations in expression of micro-, m-, and n-calpain and calpastatin after exhaustive exercise and its association with muscle injury.
  
  
  METHODS
  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.
  
  
  RESULTS
  Calpastatin protein expression and m-calpain activity increased early after exercise, but both n-calpain protein expression and micro-calpain activity generally decreased with time. n-Calpain mRNA expression was down-regulated from late after exercise.
  
  
  CONCLUSIONS
  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 micro-calpain activity was found earlier than muscle injury and therefore might serve as a useful predictor of muscle injury.
authors: First Clinical Medical College, Nanjing Medical University, and the Department of Physical Education, Southeast University, Nanjing, 210029, China.
authors: Lijing
authors: L
authors: Wang
authors: Ligong
authors: L
authors: Duan
authors: Xukan
authors: X
authors: Li
authors: Guoping
authors: G
authors: Li
mesh_terms: D000818:Animals; D001706:Biopsy; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002154:Calpain / Q000235:genetics / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010805:Physical Conditioning, Animal; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002135:Calcium-Binding Proteins; D012333:RNA, Messenger; C033668:calpastatin; D002154:Calpain