title: Effects of cyclic heat stress or vitamin C supplementation during cyclic heat stress on HSP70, inflammatory cytokines, and the antioxidant defense system in Sprague Dawley rats.
abstract: A total of 21 male SD rats were divided into three groups to investigate the effects of consecutive cyclic heat stress or vitamin C under heat stress on heat shock protein (HSP) 70, inflammatory cytokines, and antioxidant systems. The heat stress (HS) and vitamin C supplementation during heat stress (HS+VC) groups were exposed to cyclic heat stress (23 to 38 to 23°C) for 2 h on each of seven consecutive days. The HS+VC group had free access to water containing 0.5% vitamin C throughout the experiment. Hepatic HSP70 mRNA in the HS group was significantly (P<0.05) higher than that in the control (CON) or HS+VC group. The mRNA levels of tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS) in the HS group were greater (P<0.05) than those in the CON group. The HS+VC group showed significantly (P<0.05) lower mRNA levels of hepatic interleukin-6 and TNF-α than the HS group. However, thymic HSP70 and inflammatory cytokines were unaffected by treatments. In the hepatic antioxidant system, the mRNA and activity of glutathione peroxidase (GPX) were greater (P<0.05) in the HS than in the CON group, whereas the HS+VC group showed markedly (P<0.05) lower GPX mRNA and activity than the HS group. However, superoxide dismutase, glutathione S-transferase, and malondialdehyde were unaffected by treatments. In conclusion, cyclic heat stress activated hepatic HSP70, TNF-α, iNOS, and GPX genes, whereas vitamin C during heat stress ameliorated heat stress-induced cellular responses in rats.
authors.affiliation: Department of Animal Science and Biotechnology, Gyeongnam National University of Science and Technology, 150 Chilam-Dong, Jinju, Gyeongnam 660-758, Korea.
authors.forename: Seo-Hyun
authors.initials: SH
authors.lastname: Yun
authors.forename: Yang-Soo
authors.initials: YS
authors.lastname: Moon
authors.forename: Sea-Hwan
authors.initials: SH
authors.lastname: Sohn
authors.forename: In-Surk
authors.initials: IS
authors.lastname: Jang
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000008:administration & dosage*; D016207:Cytokines / Q000378:metabolism*; D019587:Dietary Supplements / Q000032:analysis; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response; D006358:Hot Temperature / Q000009:adverse effects; D007124:Immunoenzyme Techniques; D008297:Male; D009928:Organ Specificity; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D051381:Rats / Q000502:physiology*; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000975:Antioxidants; D016207:Cytokines; D018840:HSP70 Heat-Shock Proteins; D012333:RNA, Messenger; D001205:Ascorbic Acid