Regional expression of c-fos and heat shock protein-70 mRNA following hypoxia-ischemia in immature rat brain.
Cerebral ischemia induces the expression of a number of proteins that may have an important influence on cellular injury. The purpose of this study was to compare the regional effects of hypoxia-ischemia on the expression of the proto-oncogene, c-fos, and the heat shock protein-70 (HSP-70) gene in developing brain. Unilateral hypoxia-ischemia was produced in the brain of immature rats (7, 15, and 23 days after birth) using a combination of carotid artery ligation and systemic hypoxia (8% O2). After recovery for 2 and 24 h, the regional expression of c-fos and HSP-70 mRNA was determined using in situ hybridization. Littermates were permitted to recover for 1 week for assessment of histologic injury. Hypoxia-ischemia increased the expression of both c-fos and HSP-70 mRNA, but the topography of expression varied with the age of the animal as well as the mRNA species. In the 7-day-old group, expression of c-fos at 2 h increased in multiple regions of the ipsilateral hemisphere in nearly one-half of the animals, while HSP-70 mRNA was not expressed until 24 h and, then, predominantly in the hippocampus. In 15- and 23-day-old rats, expression of c-fos was increased at 2 h in the entorhinal cortex and in the dendritic field of the upper blade of the hippocampal dentate gyrus, while HSP-70 mRNA was prominently expressed in neocortex and the cell layers of the hippocampus. Interestingly, the strong expression of HSP-70 mRNA in dentate granule cells did not occur in the innermost layer of cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Blumenfeld
K S
KS
Division of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia.
Welsh
F A
FA
Harris
V A
VA
Pesenson
M A
MA
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D006624:Hippocampus / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley
D006360:Heat-Shock Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger