RESUMO
Objective To investigate the bid gene expression and cell death in brain after cerebral hypoxia-ischemia in neonatal rats and the effects of dexamethasone(DEX)on bid gene expression,so as to elucidate the possible mechanism of the neuroprotective effect of DEX pretreatment on rats following cerebral hypoxia-ischemia.Methods Twenty-four SD neonatal rats were divided randomly into hypoxia-ischemia brain damage(HIBD),normal,dexamethasone-pretreated and 9 g/L NaCl(NS)control group.The animal models of HIBD were made.Total RNA from ipsilateral cerebral hemisphere was extracted.Reverse transcription polymerase chain reaction(RT-PCR)was used to evaluate the level of bid gene expression after hypoxia-ischemia.Cerebral apoptosis was determined by terminal-deoxynucleotidy transferase mediated d-UTP nick end labeling(TUNEL).Results The levels of bid mRNA were higher in HIBD rats than those in normal rats.The number of positive apoptosis cells significantly increased in HIBD group(P