Nerve growth factor affects focal cerebral cortical neuronal Bcl-2 and Bax expression in a mouse model of oxyhemoglobin-induced subarachnoid hemorrhage

摘要

BACKGROUND:Studies have demonstrated that oxyhemoglobin(OxyHb)can induce brain cell apoptosis in vivo. OBJECTIVE:To observe the effects of exogenous nerve growth factor(NGF)on cerebral cortical neuronal Bcl-2 and Bax expression in mice with OxyHb-induced subarachnoid hemorrhage. DESIGN,TIME AND SETTING:A completely randomized grouping,controlled animal experiment was performed at the Experimental Center for Biomedicine,College of Medicine,Xi’an Jiaotong University between February and April 2005. MATERIALS:Fifty-four healthy,male,adult,ICR mice were included in this study.Subarachnoid hemorrhage was induced by a subarachnoid injection of OxyHb in 48 mice.Mouse NGF was obtained from Xiamen Beidazhilu Bioengineering Co.,Ltd.,China. METHODS:All 54 mice were randomly divided into three groups:control(n=6),injury(n=24),and NGF (n=24).The NGF group received a subarachnoidal administration of OxyHb,immediately followed by a caudal vein injection of NGF(1μg).The injury group was injected with OxyHb,and subsequently with physiological saline.The control group only received intravenous physiological saline. MAIN OUTCOME MEASURES:At 1,6,24,and 48 hours following subarachnoid hemorrhage induction, expression levels of Bcl-2 and Bax were detected by immunohistochemistry in the cerebral cortex 3 mm anterior and posterior to the injection site. RESULTS:At all time points following OxyHb injection,cerebral cortical Bax levels were significantly higher in the injured group than in the control and NGF groups(P<0.01).During the first 24 hours following OxyHb injection,cerebral cortical Bcl-2 levels were significantly lower in the injury group compared to the control group(P<0.05-0.01).Between 1 and 48 hours,Bcl-2 levels were significantly higher in the NGF group than in the injury group(P<0.01). CONCLUSION:Exogenous NGF can inhibit increased neuronal Bax expression and decreased Bcl-2 expression in the cerebral cortex of mice with OxyHb-induced subarachnoid hemorrhage.