Dose-dependent effects of procyanidin on nerve growth factor expression following cerebral ischemia/ reperfusion injury in rats★

BACKGROUND： Recently, grape seed procyanidin （GSP） has been shown to be exhibit antioxidant effects, effectively reducing ischemia/reperfusion injury and inhibiting brain cell apoptosis. OBJECTIVE： To study the effects of GSP on nerve growth factor （NGF） expression and neurological function following cerebral ischemia/reperfusion injury in rats. DESIGN： Randomized controlled study based on SD rats. SETTING： Weifang Municipal People＇s Hospital. MATERIALS： Forty-eight healthy adult SD rats weighing 280-330 g and irrespective of gender were provided by the Experimental Animal Center of Shandong University. GSP derived from grape seed was a new high-effective antioxidant provided by Tianjin Jianfeng Natural Product Researching Company （batch number： 20060107）. Rabbit-anti-rat NGF monoclonal antibody was provided by Beijing Zhongshan Biotechnology Co., Ltd., and SABC immunohistochemical staining kit by Wuhan Boster Bioengineering Co., Ltd. METHODS： The present study was performed in the Functional Laboratory of Weifang Medical College from April 2006 to January 2007. Forty-eight SD rats were randomly divided into the sham operation group, ischemia/reperfusion group, high-dose GSP （40 mg/kg） group, or low-dose GSP （10 mg/kg） group （n = 12 per group）. Ischemia/reperfusion injury was established using the threading embolism method of the middle cerebral artery. Rats in the ischemia/reperfusion model group were given saline injection （2 mL/kg i.p.） once daily for seven days pre-ischemia/reperfusion, and once more at 15 minutes before reperfusion. Rats in the high-dose and low-dose GSP groups were injected with GSP （20 or 5 mg/mL i.p., respectively, 2 mL/kg） with the same regime as the ischemia/reperfusion model group. The surgical procedures in the sham operation group were as the same as those in the ischemia/reperfusion model group, but the thread was approximately 10 mm long, thus, the middle cerebral artery was not blocked. MAIN OUTCOME MEASURES： NGF expression in the

Dose-dependent effects of procyanidin on nerve growth factor expression following cerebral ischemia/ reperfusion injury in rats

BACKGROUND: Recently, grape seed procyanidin (GSP) has been shown to be exhibit antioxidant effects, effectively reducing ischemia/reperfusion injury and inhibiting brain cell apoptosis.OBJECTIVE: To study the effects of GSP on nerve growth factor (NGF) expression and neurological function following cerebral ischemia/reperfusion injury in rats.DESIGN: Randomized controlled study based on SD rats.SETTING: Weifang Municipal People's Hospital. MATERIALS: Forty-eight healthy adult SD rats weighing 280-330 g and irrespective of gender were provided by the Experimental Animal Center of Shandong University. GSP derived from grape seed was a new high-effective antioxidant provided by Tianjin Jianfeng Natural Product Researching Company (batch number: 20060107). Rabbit-anti-rat NGF monoclonal antibody was provided by Beijing Zhongshan Biotechnology Co., Ltd., and SABC immunohistochemical staining kit by Wuhan Boster Bioengineering Co., Ltd. METHODS: The present study was performed in the Functional Laboratory of Weifang Medical College from April 2006 to January 2007. Forty-eight SD rats were randomly divided into the sham operation group, ischemia/reperfusion group, high-dose GSP (40 mg/kg) group, or low-dose GSP (10 mg/kg) group (n = 12 per group). Ischemia/reperfusion injury was established using the threading embolism method of the middle cerebral artery. Rats in the ischemia/reperfusion model group were given saline injection (2 mL/kg i.p.) once daily for seven days pre-ischemia/reperfusion, and once more at 15 minutes before reperfusion. Rats in the high-dose and low-dose GSP groups were injected with GSP (20 or 5 mg/mL i.p., respectively, 2 mL/kg) with the same regime as the ischemia/reperfusion model group. The surgical procedures in the sham operation group were as the same as those in the ischemia/reperfusion model group, but the thread was approximately 10 mm long, thus, the middle cerebral artery was not blocked. MAIN OUTCOME MEASURES: NGF expression in the ischemic penumbra of the temporal cortex was detected by immunohistochemistry, and positive cells counted by light microscopy (×400). The positive cell rate was calculated by (positive cells/total cells) × 100%]. Neurological function was scored after 2-hour ischemia/48-hour reperfusion. Higher scores reflected more severe neurofunctional defect. RESULTS: The positive rate of NGF expression in all groups receiving ischemia/reperfusion was significantly higher than that in the sham operation group (q=3.87, P < 0.05). The positive rate of NGF expression in the high-dose and low-dose GSP groups were significantly higher than that in the model group (q=4.12, P < 0.05), and were greater in the high-dose compared to low-dose GSP groups (q=4.22, P < 0.05). Neurological function scores in the high-dose and low-dose GSP groups were significantly lower than that in the ischemia/reperfusion model group (q=3.92, P < 0.05). Neurological function score in the high-dose GSP group was significantly less than that in the low-dose GSP group (q=4.02, P < 0.05). CONCLUSION: GSP may up-regulate brain-derived NGF expression in a dose-dependent manner following cerebral ischemia/reperfusion injury in order to improve neurological function and protect the brain.