Abstract
An inflammatory response triggered by neutrophil accumulation into muscle tissue is thought to occur with exercise-induced muscle damage. To investigate the relationship between Ca2+-stimulated proteolysis (calpain-like activity) and neutrophil accumulation [myeloperoxidase (MPO) activity], cardiac and plantaris muscles from rats (n = 10) completing 1 h exercise (25 m/min) were investigated. Exercise promoted increases (P<0.05) in both calpain-like and MPO activities; ranging from 2.79 to 58.9 U/g wet weight (ww) and 0.03 to 4.88 U/g ww respectively. Pearson’s correlational analysis (r) on calpain-like and MPO activities for cardiac and plantaris muscle data were 0.97 (P<0.001) and 0.68 (P<0.05) respectively, with a combined r of 0.83 (P<0.001) for both muscles across all conditions. To investigate further the extent to which calpain-like activity may promote neutrophil accumulation, another exercise group (n = 5) was pre-injected with the cysteine protease inhibitor, E64c, 1 h before exercise. Administration of E64c lowered calpain-like and MPO activities by 66% and 56% respectively (average from both muscles). From these results it is concluded that a relationship exists between Ca2+-stimulated proteolysis and neutrophil accumulation into striated muscle with exercise, and that the calpain system is involved in localizing the neutrophilic response with exercise.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 3 February 1997 / Received after revision: 18 August 1997 / Accepted: 2 December 1997
Rights and permissions
About this article
Cite this article
Raj, D., Booker, T. & Belcastro, A. Striated muscle calcium-stimulated cysteine protease (calpain-like) activity promotes myeloperoxidase activity with exercise. Pflügers Arch 435, 804–809 (1998). https://doi.org/10.1007/s004240050587
Issue Date:
DOI: https://doi.org/10.1007/s004240050587