title: Heat stress protects against mechanical ventilation-induced diaphragmatic atrophy.
abstract: Mechanical ventilation (MV) is a life-saving intervention in patients who are incapable of maintaining adequate pulmonary gas exchange due to respiratory failure or other disorders. However, prolonged MV is associated with the development of respiratory muscle weakness. We hypothesized that a single exposure to whole body heat stress would increase diaphragm expression of heat shock protein 72 (HSP72) and that this treatment would protect against MV-induced diaphragmatic atrophy. Adult male Wistar rats (n = 38) were randomly assigned to one of four groups: an acutely anesthetized control group (CON) with no MV; 12-h controlled MV group (CMV); 1-h whole body heat stress (HS); or 1-h whole body heat stress 24 h prior to 12-h controlled MV (HSMV). Compared with CON animals, diaphragmatic HSP72 expression increased significantly in the HS and HSMV groups (P < 0.05). Prolonged MV resulted in significant atrophy of type I, type IIa, and type IIx fibers in the costal diaphragm (P < 0.05). Whole body heat stress attenuated this effect. In contrast, heat stress did not protect against MV-induced diaphragm contractile dysfunction. The mechanisms responsible for this heat stress-induced protection remain unclear but may be linked to increased expression of HSP72 in the diaphragm.
authors: School of Health and Sports Science, Juntendo University, Inzai, Chiba, Japan; nsekine@juntendo.ac.jp.
authors: Noriko
authors: N
authors: Ichinoseki-Sekine
authors: School of Health and Sports Science, Juntendo University, Inzai, Chiba, Japan;
authors: Toshinori
authors: T
authors: Yoshihara
authors: School of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan;
authors: Ryo
authors: R
authors: Kakigi
authors: Faculty of Education, Yamaguchi University, Yamaguchi, Yamaguchi, Japan; and.
authors: Takao
authors: T
authors: Sugiura
authors: Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida.
authors: Scott K
authors: SK
authors: Powers
authors: School of Health and Sports Science, Juntendo University, Inzai, Chiba, Japan;
authors: Hisashi
authors: H
authors: Naito
mesh_terms: D000818:Animals; D001284:Atrophy; D001784:Blood Gas Analysis; D001835:Body Weight / Q000502:physiology; D003964:Diaphragm / Q000378:metabolism / Q000503:physiopathology*; D050884:HSP72 Heat-Shock Proteins / Q000096:biosynthesis; D018882:Heat Stress Disorders / Q000378:metabolism / Q000503:physiopathology*; D006358:Hot Temperature; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012121:Respiration, Artificial / Q000009:adverse effects*
chemical_list: D050884:HSP72 Heat-Shock Proteins
keywords: antioxidants; heat shock protein; proteolysis; respiratory muscle weakness