淫羊藿苷对脑缺血再灌注大鼠恢复早期的神经保护作用研究

The Neuroprotective Effects of Icariin on Focal Cerebral Ischemia Reperfusion Injured Rats during Early Recovery Period

目的探讨淫羊藿苷对脑缺血再灌注大鼠恢复早期的神经保护作用及其机制。方法采用线栓法制备局灶性脑缺血再灌注大鼠模型。造模成功后(术后24 h)将大鼠随机分为假手术组,模型组,丁苯酞组(70 mg·kg^-1),淫羊藿苷高、中、低剂量组(80、40、20 mg·kg^-1),灌胃相应药物(10 mL·kg^-1),每天给药1次,连续给药13 d。术后第3、9、14天,对大鼠进行神经功能评分,通过横木行走实验进行平衡能力评分,通过胶布揭除实验进行触觉功能检测。采用TUNEL法检测大鼠脑缺血周围区大脑皮层神经细胞凋亡情况;采用免疫组化法检测大鼠脑缺血周围区大脑皮层B细胞淋巴瘤因子-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、半胱氨酸蛋白酶-3(Caspase-3)表达情况。结果术后第14天,与假手术组比较,模型组大鼠的神经功能评分明显升高(P <0.01),横木行走评分均明显降低(P <0.01),揭除胶布的潜伏期显著延长(P <0.01),缺血周围区大脑皮层神经细胞凋亡率及Bcl-2、Bax、Caspase-3阳性表达水平均显著升高(P <0.01)。与模型组比较,各给药组大鼠的神经功能评分和神经细胞凋亡率均明显降低(P <0.05,P <0.01),大鼠脑组织Bcl-2阳性表达水平均显著升高(P <0.05,P <0.01),Bax阳性表达水平均显著降低(P <0.05,P <0.01);淫羊藿苷高、中剂量组大鼠的横木行走评分均明显升高(P <0.05,P <0.01),大鼠揭除胶布的潜伏期均明显缩短(P <0.05),大鼠脑组织Caspase-3阳性表达水平均显著降低(P <0.05,P <0.01)。结论淫羊藿苷对脑缺血再灌注大鼠恢复早期具有明显的神经保护作用,其改善神经功能缺损的机制可能与上调大脑皮层Bcl-2、下调大脑皮层Bax及Caspase-3表达,从而抑制神经细胞凋亡有关。

Objective To investigate the neuroprotective effect and its mechanisms of icariin on focal cerebral ischemia reperfusion injured rats during early recovery period. Methods The rat model of focal cerebral ischemia reperfusion was established by suture method. After 24 hours, rats were randomly divided into Sham operation group, model group, Butylphthalide group(70 mg · kg^-1), and high, medium and low dose groups(80, 40,20 mg·kg^-1)of icariin. The volume of gastric administration was 10 mL·kg^-1 once daily for 13 d. At 3,9 and 14 days after modelling,the neurological symptoms of rats were scored;the balance function was scored according to beam walking test,and tactile function was accessed using adhesive tape exposed test. The apoptotic rate of neurons in cerebral cortex was detected by TUNEL method. Immunohistochemical method was used to detect the expression of B cell lymphoma factor-2(Bcl-2),Bcl-2 related X protein(Bax)and cysteine protease-3(Caspase-3)in cerebral cortex. Results On 14th day of modelling,compared with the Sham operation group,the neurological symptoms scores in the model control group were increased(P < 0.01),the balance ability and tactile function were reduced(P < 0.01),percentage of apoptotic nerve cells and the expression of Bcl-2,Bax and Caspase-3 around the lesion area were significantly increased(P < 0.01). Compared with the model group,the neurological symptom scores and percentage of apoptotic nerve cells in the drug groups were reduced(P < 0.05,P < 0.01),the expression of Bcl-2 were significantly increased(P < 0.05,P < 0.01),the expression of Bax were significantly reduced(P < 0.05,P <0.01);but the balancing ability and tactile function in 40 and 80 mg·kg-1 of icariin groups were significantly improved and the expression of Caspase-3 were significantly reduced(P < 0.05,P < 0.01). Conclusion Icariin has a significant protective effect on focal cerebral ischemia reperfusion injured rats during early recovery period,which may be related to the increase expression of Bcl-2 and decrease those of Bax and Caspase-3, and the further inhibition of neuronal apoptosis.