Fatiguing stimulation of one skeletal muscle triggers heat shock protein activation in several rat organs: the role of muscle innervation.
We hypothesised that activation of muscle afferents by fatigue triggers a widespread activation of heat shock proteins (HSPs) in resting muscles and different organs. In anaesthetised rats, HSP25 and HSP70 levels were determined in both tibialis anterior (TA) and extensor digitorum longus (EDL) muscles and in the diaphragm, kidney and brain by ELISA, which mostly identifies phosphorylated HSP, and western blotting. One TA muscle was electrically stimulated and tissues were sampled 10 or 60 min after the stimulation had ended. The nerve supply to the stimulated TA or its counterpart in the contralateral limb was left intact or suppressed. In control rats, no muscle stimulation was performed and tissues were sampled at the same time points (10 or 60 min). After TA stimulation, ELISA showed an increased HSP25 content in the contralateral TA, EDL and diaphragm at 10 min but not at 60 min, and HSP70 increased in all sampled tissues at 60 min. Western blotting did not show any changes in HSP25 and HSP70 at 10 min, while at 60 min HSP25 increased in all sampled tissues except the brain and HSP70 was elevated in all tissues. Denervation of the contralateral non-stimulated limb suppressed HSP changes in TA and after denervation of the stimulated TA the widespread activation of HSPs in other organs was absent. Our data suggest that fatigue-induced activation of skeletal muscle afferents triggers an early increase in phosphorylated HSP25 in muscles and a delayed elevation of non-phosphorylated HSP25 and HSP70 in skeletal and respiratory muscles, kidney and brain.
UMR MD2, Faculty of Medicine, Aix-Marseille University, Marseille, France. yves.jammes@univ-amu.fr
Yves
Y
Jammes
Jean Guillaume
JG
Steinberg
Youlet
Y
By
Christelle
C
Brerro-Saby
Jocelyne
J
Condo
Marine
M
Olivier
Regis
R
Guieu
Stephane
S
Delliaux
D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism; D001696:Biomechanical Phenomena / Q000502:physiology; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology*; D009928:Organ Specificity; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D012146:Rest; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486114:Hspb1 protein, rat; D017392:Thiobarbituric Acid Reactive Substances; D001205:Ascorbic Acid