A possible role of NF-kappaB and HSP72 in skeletal muscle hypertrophy induced by heat stress in rats.
Effects of heat stress on phosphorylated nuclear factor-kappaB (phospho-NF-kappaB) and tumor necrosis factor alpha (TNFalpha) contents in skeletal muscles were studied. Male Wistar rats (7-week-old) were randomly assigned to control and heat-stressed groups. Rats in heat-stressed group were exposed to heat stress (42 degrees C for 60 min) in an incubator without anesthesia. Soleus muscles were dissected and weighted 1, 3, and 7 days after the heat exposure. Significant increases in the wet weight and protein content of soleus were observed 7 days following the exposure (p < 0.05). Heat stress also induced the up-regulation of heat shock protein 72 (HSP72), IkappaBalpha (inhibitor of NF-kappaB) and the increase in the relative population of Pax7-positive satellite cells to total muscle nuclei before the increase in muscle mass. The content levels of phospho-NF-kappaB and TNFalpha were significantly decreased 1 and 3 days after heat stress, respectively (p < 0.05). A negative correlation between HSP72 and phospho-NF-kappaB contents was observed 1 day after the heat exposure. These observations suggest that the decrease in NF-kappaB signaling may play a part of a role in heat stress-associated muscle hypertrophy.
Ohno
Yoshitaka
Y
School of Health Sciences, Toyohashi SOZO University, Aichi 440-8511, Japan.
Yamada
Sumio
S
Sugiura
Takao
T
Ohira
Yoshinobu
Y
Yoshioka
Toshitada
T
Goto
Katsumasa
K
D000818:Animals; D050884:HSP72 Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology*; D006984:Hypertrophy / Q000378:metabolism / Q000473:pathology; D020672:I-kappa B Proteins / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D051761:Paired Box Transcription Factors / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation
D050884:HSP72 Heat-Shock Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606206:Nfkbia protein, rat; C530821:PAX7 protein, rat; D051761:Paired Box Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha