Objective: To investigate the effect and mechanisms of picroside Ⅱ on the brain tissue after cerebral ischemia reperfusion(I/R) in rats. Methods: The middle cerebral artery occlusion(MCAO) rat model was established by inserting a monofilament into middle cerebral artery. The experimental rats were treated by injecting picroside Ⅱ intraperitoneally. The modified neurological severity score (mNSS) and body weight were determined before modeling and after reperfusion of 22 h. The cerebral infarct volume was measured by TTC staining and the cerebral water content was measured in rats. At the same time, ROS content and NADPH oxidase activity were detected. The structure of neurons was observed by electron microscope and the mRNA and protein levels of Rac-1 and Nox2 were detected by RT-PCR and Western blotting. Results: After modeling, the mNSS score was significantly increased (12.6±1.3 vs 0, P<0.001), while the body weight was lost (13.3%±2.5% vs 4.9%±0.8%, P<0.01). The cerebral infarct volume increased obviously (33.5%±3.4% vs 0, P<0.001), brain water content increased significantly (81.5%±0.9% vs 77.7%±0.9%, P<0.05) and the structure of neuron was damaged obviously. The protein and mRNA levels of Rac-1 and Nox2 were significantly increased (P<0.05). After treatment with picroside Ⅱ, mNSS score decreased significantly (7.9±0.8 vs 12.6±1.3, P<0.05) and the body weight increased obviously (9.3%±1.1% vs 13.3%±2.5%, P<0.05). The infarct volume of brain was significantly reduced (18.2%±1.9% vs 33.5%±3.4%, P<0.05), brain water content decreased obviously (79.1%±0.7% vs 81.5±0.9%, P<0.05), the morphological structures of neurons was restored, and the expressions of Rac-1 and Nox2 were significantly decreased (P<0.05). Conclusion: It is suggested that picroside Ⅱ could exert antioxidation to protect the brain tissue through inhibiting the expression of Rac-1 and Nox2.
目的： 探索胡黄连苷Ⅱ在大鼠脑缺血再灌注(I/R)后对脑组织细胞的保护作用及机制。 方法： 应用栓线法建立大鼠大脑中动脉栓塞(MCAO)模型，腹腔注射胡黄连苷Ⅱ干预治疗。造模前及再灌注22 h后，对大鼠神经行为学进行mNSS评分和体质量测定，大鼠脑缺血2 h再灌注22 h后，TTC染色测量梗死体积，干－湿重法测定大鼠脑含水量，电镜下观察神经元的结构，运用试剂盒测定活性氧(ROS)含量和NADPH氧化酶的活性，Western印迹、RT－PCR检测Rac－1和Nox2的蛋白和mRNA表达水平。 结果： 大鼠造模后，mNSS评明显增高(12.6±1.3比0, P<0.001)，体质量明显减轻(13.3%±2.5%比4.9%±0.8%, P<0.01)，皮质区梗死明显(33.5%±3.4%比0, P<0.001)，脑含水量明显增加(81.5%±0.9%比77.7%±0.9%, P<0.05)、神经元结构形态遭到破坏，ROS含量和NADPH氧化酶活性显著提高；且脑皮质区Rac－1、Nox2的蛋白及基因表达均较假手术组明显升高(P<0.05)。经胡黄连苷Ⅱ治疗后，mNSS评分明显降低(7.9±0.8比12.6±1.3, P<0.05)，体质量增加(9.3%±1.1%比13.3%±2.5%, P<0.05)，大鼠脑组织梗死体积明显缩小(18.2%±1.9%比33.5%±3.4%, P<0.05)，脑含水量下降(79.1%±0.7%比81.5%±0.9%, P<0.05)，神经元形态结构明显恢复，ROS含量和NADPH氧化酶活性显著降低，Rac－1、Nox2的蛋白及基因表达均明显下降(P<0.05)。以上实验结果表明胡黄连苷Ⅱ对脑I/R后的脑组织及神经元细胞有较好的保护作用。 结论： 胡黄连苷Ⅱ可能通过降低Rac－1和Nox2的基因及蛋白表达来降低活性氧的产生，拮抗脑缺血再灌注带来的氧化应激损伤，发挥神经保护作用。.
Keywords: Cerebral ischemia; Neurons; Oxidative stress.