Gene expression levels of heat shock proteins in the soleus and plantaris muscles of rats after hindlimb suspension or spaceflight.
Gene expression levels of heat shock proteins (HSPs) in the slow-twitch soleus and fast-twitch plantaris muscles of rats were determined after hindlimb suspension or spaceflight. Male rats were hindlimb-suspended for 14 d or exposed to microgravity for 9 d. The mRNA expression levels of HSP27, HSP70, and HSP84 in the hindlimb-suspended and microgravity-exposed groups were compared with those in the controls. The mRNA expression levels of the 3 HSPs in the soleus muscle under normal conditions were higher compared with those in the plantaris muscle. The mRNA expression levels of the 3 HSPs in the soleus muscle were inhibited by hindlimb suspension and spaceflight. The mRNA expression levels of the 3 HSPs in the plantaris muscle did not change after hindlimb suspension. It is suggested that the mRNA expression levels of the 3 HSPs are regulated by the mechanical and neural activity levels, and therefore the decreased mRNA expression levels of HSPs in the slow-twitch muscle following hindlimb suspension and spaceflight are related to a reduction in the mechanical and neural activity levels.
Laboratory of Neurochemistry, Graduate School of Human and Environmental Studies, Kyoto, University, Kyoto,606-8501 Japan. ishihara@life.mbox.media.kyoto-u.ac.jp
Akihiko
A
Ishihara
Hidemi
H
Fujino
Fumiko
F
Nagatomo
Isao
I
Takeda
Yoshinobu
Y
Ohira
D000818:Animals; D005786:Gene Expression Regulation; D055551:HSP27 Heat-Shock Proteins / Q000235:genetics; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D019417:Hindlimb Suspension; D008297:Male; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013026:Space Flight; D014893:Weightlessness
D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D012333:RNA, Messenger