title: Lipoic Acid Exerts Antioxidant and Anti-inflammatory Effects in Response to Heat Shock in C2C12 Myotubes.
abstract: This study explored that lipoic acid treatment for 24 h significantly upregulated and promoted heat shock-induced catalase expression and downregulated GPx1 messenger RNA (mRNA) expression, indicating that lipoic acid exhibits antioxidant activity in the decomposition of hydrogen peroxide by upregulating catalase expression. Moreover, lipoic acid treatment for 3 h increased and promoted heat shock-induced interleukin (IL)-6 mRNA and protein levels and that for 24 h downregulated IL-6 mRNA expression, suggesting a dual effect of lipoic acid on IL-6 regulation. Lipoic acid alone failed to increase or reduce tumor necrosis factor (TNF)-α mRNA and protein levels, whereas heat shock alone downregulated TNF-α mRNA and protein expression. These data suggest that lipoic acid does not have a proinflammatory role and that heat shock acts as an anti-inflammatory agent by downregulating TNF-α expression in C2C12 myotubes. Moreover, lipoic acid or heat shock alone upregulated the IL-6 receptor (IL-6R-α) and glycoprotein 130 (gp130) mRNA expression followed by IL-6 expression; these data indicate that the regulation of lipoic acid or heat shock is mediated by IL-6R signaling, thus suggesting that C2C12 myotubes possesses a mechanism for regulating IL-6R and gp130 expression following lipoic acid treatment or heat shock.
authors.affiliation: Division of Orthopedics, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan.
authors.forename: Cheng-Tse
authors.initials: CT
authors.lastname: Lee
authors.affiliation: Department of Occupational Therapy, I-Shou University, Kaohsiung, Taiwan.
authors.forename: Li-Ching
authors.initials: LC
authors.lastname: Chang
authors.affiliation: Department of Kinesiology, Health and Leisure Studies, National University of Kaohsiung, Kaohsiung, Taiwan. anniepf@nuk.edu.tw.
authors.forename: Pei-Fung
authors.initials: PF
authors.lastname: Wu
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents; D000975:Antioxidants; D002478:Cells, Cultured; D050822:Cytokine Receptor gp130 / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D018869:Heat-Shock Response / Q000187:drug effects*; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis / Q000187:drug effects; D019947:Receptors, Interleukin-6 / Q000235:genetics; D008063:Thioctic Acid / Q000494:pharmacology*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D000893:Anti-Inflammatory Agents; D000975:Antioxidants; C494200:Il6st protein, mouse; D012333:RNA, Messenger; D019947:Receptors, Interleukin-6; D014409:Tumor Necrosis Factor-alpha; C113250:interleukin-6 receptor alpha; D050822:Cytokine Receptor gp130; D008063:Thioctic Acid
keywords: IL-6; IL-6R; TNF-α; gp130; heat shock; lipoic acid