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

Xianfeng Jiang; Wei Shi; Jin Liang

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 Xiamcn 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 (1 μg). The injury group was injected with OxyHb, and subsequently with physiological saline. Thc 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-2expression in the cerebral cortex of mice with OxyHb -induced subarachnoid hemorrhage.