Heat Stress Suppresses Skeletal Muscle Damage after Downhill Running

Accession number;03A0438040
Title;Heat Stress Suppresses Skeletal Muscle Damage after Downhill Running
Author; MIKAMI TOSHIO (Nippon Med. Sch.) OTA SHIGEO (Nippon Med. Sch.)
Journal Title;Descente Sports Science
Journal Code:L0988A
ISSN:0285-5739
VOL.24;NO.;PAGE.145-152(2003)
Figure&Table&Reference;FIG.5, REF.26
Pub. Country;Japan
Language;Japanese
Abstract;These experiments were designed to investigate whether elevation of heat shock protein 70 (HSP70) in skeletal muscle prior to exercise contributes to protect from skeletal muscle damege induced by eccentric exercise In experiment 1, male ICR mice were exposed to 30 min of heyperthermia at 42.DEG.C.. Soleus and extensor digitorum longus (EDL) were excised under the anaesthesia 24h after the exposure to heat. The amount of HSP70 in both skeletal muscles was determined by SDS-PAGE and western blot. Heat stress significantly increased the amount of HSP70 in both soleus and EDL muscle compared with the resting level. In experiment 2, male ICR mice were divided into two groups, exercise group and heat+exercise group. Heat+exercise group of mice was exposed to the same heat stress 24h before exercise as experiment 1. Both groups of mice performed 60 min of downhill running (-20 degrees, 25 m/min). Skeletal muscles and plasma were removed under anesthezisis 12, 24 and 48h after downhill running. Creatine kinase (CK) activity in plasma increased 12h and 24h after downhill running, while .BETA.-glucuronidase activity in soleus and EDL increased 48h after downhill running. However, heat+exercise group of mice showed more suppressed level in both enzyme activities compared with exercise group. These finding suggest that heat stress prior to downhill running induces skeletal muscle HSP70 and leads to protective effect against skeletal muscle injury induced by downhill running. (author abst.)