桃叶鸦葱黄酮对脑缺血再灌注大鼠的保护作用

Study on Neuroprotective Effect of Total Flavonoids from Scorzonera sinensis on Cerebral Ischemia Reperfusion Injury in Rats

目的:探讨桃叶鸦葱总黄酮对脑缺血-再灌注大鼠的保护作用。方法:72只清洁级雄性健康SD大鼠,随机分成假手术组、模型组、模型+桃叶鸦葱总黄酮高剂量组(400 mg·kg^(-1)),模型+桃叶鸦葱总黄酮中剂量组(200 mg·kg^(-1)),模型+桃叶鸦葱总黄酮低剂量组(100 mg·kg^(-1)),模型+尼莫地平组(10.8 mg·kg^(-1)),每组12只。模型组和用药组采用大脑中动脉线栓法制备大鼠脑缺血-再灌注损伤模型,在缺血2 h后再灌注,连续给药20 d,对各组大鼠进行神经行为学评分、脑组织含水量测定、通过HE染色观察其脑组织病理形态学改变、通过免疫组织化学联合图像分析方法检测其海马区水通道蛋白4(AQP4)的表达。结果:模型组大鼠均表现出明显的神经功能缺损症状,神经行为学评分升高,而桃叶鸦葱高、中剂量组及尼莫地平组大鼠症状改善,神经行为学评分降低(P<0.05)。大鼠脑含水量实验表明,模型组大鼠脑含水量显著高于假手术组(P<0.01),桃叶鸦葱总黄酮高、中剂量组和尼莫地平组大鼠脑含水量显著低于模型组(P<0.05)。HE染色结果显示,模型组大鼠海马区神经元细胞脱失明显,而高、中剂量桃叶鸦葱总黄酮及尼莫地平可减轻这种形态学改变;免疫组织化学分析结果提示,模型组中AQP4表达明显高于假手术组(P<0.01)。结论:在脑缺血-再灌注损伤过程中,AQP4水平的增高可能引起细胞对水的通透性增加,从而造成细胞损伤,导致大鼠出现神经功能缺损症状,高、中剂量桃叶鸦葱总黄酮及尼莫地平可以通过降低海马区AQP4的表达,减轻脑水肿程度,保护神经元细胞,改善大鼠神经功能损害。

Objective:To study the neuroprotective effect of the total flavonoids from Scorzonera sinensis on cerebral ischemia reperfusion injury in rats.Methods:72 male SD rats were randomly divided into 6 groups:sham-operated group,cerebral ischemia reperfusion model group,positive control group(nimodipine,10.8 mg·kg-1)and three groups of different doses of the total flavonoids from S.sinensis(400,200,100 mg·kg-1,n=12).The cerebral ischemia-reperfusion model was prepared by middle cerebral artery Occlusion(MCAO)-reperfusion method and reperfusion was performed 2 hours after ischemia.After continuous dosing for 20 d,the neurobehavioral score of rats was graded.The brain water content was determined;the rats’tissue pathological morphological changes were showed by HE staining and the expression of AQP4 in hippocampus of rats was detected with immunohistochemistry.Results:It was showed that model group rats had high neurobehavioral scores and showed obvious symptoms of nerve function defect,while the neurobehavioral scores of high and middle dose total flavonoids and nimodipine groups rats were significantly lower than those of the model group rats’and showed slight nerve function defect(P<0.05).Compared with model group,high and middle dose of total flavonoids and nimodipine can effectively reduce the cerebral water content in ischemia-reperfusion rats.HE staining showed that the neurons’structure of model group rats had been destroyed,but high and middle dose of total flavonoids and nimodipine could improve this kind of morphology damage.Immunohistochemistry analysis results suggested that the level of AQP4 in the model group rats were significantly higher than those in the sham group(P<0.01).The level of AQP4 in high and middle dose of total flavonoids and nimodipine group rats were significantly lower than those in the model group(P<0.01).Conclusion:The cerebral ischemia-reperfusion could cause neuron cells’damage by increasing AQP4,high and middle dose of total flavonoids from S.sinensis and nimodipine could reduce its expression level and improve the nerve defect symptoms.