title: Hypothermia decreased the expression of heat shock proteins in neonatal rat model of hypoxic ischemic encephalopathy.
abstract: Hypothermia (HT) is a well-established neuroprotective strategy against neonatal hypoxic ischemic encephalopathy (HIE). The overexpression of heat shock proteins (HSP) has been shown to provide neuroprotection in animal models of stroke. We aimed to investigate the effect of HT on HSP70 and HSP27 expression in a neonatal rat model of HIE. Seven-day-old rat pups were exposed to hypoxia for 90 min to establish the Rice-Vannucci model and were assigned to the following four groups: hypoxic injury (HI)-normothermia (NT, 36 °C), HI-HT (30 °C), sham-NT, and sham-HT. After temperature intervention for 24 h, the mRNA and protein expression of HSP70 and HSP27 were measured. The association between HSP expression and brain injury severity was also evaluated. The brain infarct size was significantly smaller in the HI-HT group than in the HI-NT group. The mRNA and protein expression of both HSPs were significantly greater in the two HI groups, compared to those in the two sham groups. Moreover, among the rat pups subjected to HI, HT significantly reduced the mRNA and protein expression of both HSPs. The mRNA expression level of the HSPs was proportional to the brain injury severity. Post-ischemic HT, i.e., a cold shock attenuated the expression of HSP70 and HSP27 in a neonatal rat model of HIE. Our study suggests that neither HSP70 nor HSP27 expression is involved in the neuroprotective mechanism through which prolonged HT protects against neonatal HIE.
authors.affiliation: Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-Ro 43-Gil, Songpa-Gu, Seoul, 138-736, South Korea. mdleebs@amc.seoul.kr.
authors.forename: Byong Sop
authors.identifier: 0000-0002-1347-4200
authors.initials: BS
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-Ro 43-Gil, Songpa-Gu, Seoul, 138-736, South Korea.
authors.forename: Euiseok
authors.initials: E
authors.lastname: Jung
authors.affiliation: Medical School, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Yeonjoo
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Kyung Hee University School of Medicine, Seoul, South Korea.
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Chung
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004195:Disease Models, Animal; D055551:HSP27 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D007035:Hypothermia; D020925:Hypoxia-Ischemia, Brain / Q000378:metabolism / Q000473:pathology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012720:Severity of Illness Index
chemical_list: D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins
keywords: Heat shock protein; Hypothermia; Hypoxic ischemic encephalopathy; Newborn infant