大鼠脑缺血后缺血区BDNF表达变化及通心络的影响

目的观察大鼠脑缺血后缺血区BDNF mRNA及蛋白表达水平的变化及通心络对其的影响。方法健康雄性SD大鼠随机分为:假手术组、模型组、通心络高剂量(2.24g.kg-1.d-1)、低剂量(1.12g.kg-1.d-1)组。采用线栓法制备大鼠大脑中动脉梗死(MCAO)局灶性脑缺血模型,逆转录—聚合酶链反应(RT-PCR)及免疫组化法检测脑缺血后3h、24h、72h、7d缺血区BDNF mRNA及蛋白表达的变化以及通心络的作用。结果(1)大鼠脑缺血后缺血区BDNF表达变化:大鼠局灶性脑缺血后3h缺血区BDNF mRNA表达略有上升,而24h表达下降,72h后又开始上升,至缺血后7d达高峰;免疫组化染色显示:在脑组织缺血区,BDNF主要在小神经元阳性表达,表达趋势与mRNA基本吻合。(2)通心络对缺血区BDNF表达的影响:与模型组相比,通心络高剂量组BDNF mRNA的表达水平在缺血后3h、24h、7d均有显著提高(P<0.01,P<0.05);通心络低剂量组BDNF mRNA的表达水平在缺血后3h、24h有明显升高(P<0.01,P<0.05);在缺血后7d,高剂组BD-NF mRNA的表达与低剂组相比明显升高(P<0.01)。在缺血后各时间点,通心络各组BDNF阳性神经元数量增多。结论局灶性脑缺血可促进缺血区内源性神经保护因子BDNF高表达;通心络可增强和延长缺血区BDNF高表达,发挥对脑缺血的保护作用。

The BDNF expression of brain tissue in focal cerebral ischemia in rats and the interventional effects of Tongxinluo capsule

Objective To investigate the expression of BDNF mRNA and protein after focal cerebral ischemia in rats and the interventional effects of Tongxinluo capsule.Methods The healthy male SD rats were divided into 4 groups, including sham group, model group, high dose Tongxinluo capsule group （2.24 g·kg^-1.·d^-1 ）and low dose Tongxinluo capsule group （ 1.12 g·kg^-1.·d^-1 ）. The focal cerebral ischemic injury model rats were induced with inserting nylon thread into the onset of middle cerebral artery. After 3h,24h, 72h, 7d, the RT-PCR and the immunohistochemical staining were used to determine the expression of BDNF mRNA and the interventional effects of Tongxinluo capsule. Results （1） The BDNF expression Of brain tissue in rats subjected with focal cerebral ischemia. The expression of BDNF mRNA increased slightly at 3h after focal cerebral ischemia, while decreased at 24h, then increased again at 72h after focal ischemia and reached peak at 7d staining results displayed that iu focal cerebral ischemia area, the BDNF was focused on small neuren, coincided with its expression at mRNA level. （2） The interventional effects of Tongxinluo capsule. Compared with model group, the expression of BDNF mRNA in high dose Tongxinluo capsule group was increased significantly after 3 h, 24 h and 7 d（ P 〈0.01 or P 〈 0.05）.In low dose Tongxinluo capsule group, the BDNF mRNA expression was increased since 3 h,24 h,respectively （ P 〈0.01 or P 〈 0.05）.At 7d after model set up,the BDNF mRNA expression was higher-than that in high dose group（ P 〈 0.01 ）. At every time point after focal ischemia, the amounts of positive neuron increased obviously in Tongxinluo groups. Conclusion The expression of BDNF after focal brain ischemia, which was an endogenous neu- roprotective factor,was promoted to facilitate the neuron injury recovery. The traditional Chinese medicine Tongxinluo capsule could enhance and prolong the expression of BDNF, which may be helpful to the focal cerebral injury recovery.