基于IL-33/ST2L通路研究黄芩苷对缺血性脑卒中大鼠的神经保护作用

Study on tneuroprotective effect of baicalin on rats with ischemic stroke based on IL-33/ST2L pathway

目的:探讨黄芩苷对缺血性脑卒中大鼠的神经功能及IL-33/白介素1受体样1(ST2L)信号通路的影响。方法:将90只大鼠随机分为假手术组、模型组、尼莫地平组[0.4 mg/(kg·d)]、黄芩苷低、中、高剂量组[50、100、150 mg/(kg·d)],改良Longa线栓法构建缺血性脑卒中大鼠模型。建模24 h后,Longa评分对所有大鼠神经功能损伤进行评分;ELISA法检测大鼠血清IL-6、TNF-α水平;2,3,5-三苯基氯化四唑(TTC)染色测定大鼠脑梗死面积;苏木素-伊红(HE)染色观察大鼠脑组织病理学变化;免疫组化法检测大鼠脑组织小胶质细胞数目;Western blot检测大鼠脑组织中IL-33/ST2L通路蛋白表达。结果:假手术组大鼠脑组织海马区未发生水肿,组织排列层次分明,神经元细胞结构正常;模型组大鼠海马区出现严重水肿,神经元紊乱,细胞核固缩、坏死,神经元细胞大量死亡;尼莫地平组、黄芩苷低、中、高剂量组大鼠水肿程度减轻,神经元细胞、变性、死亡数量减少,随着黄芩苷剂量增加,水肿程度逐渐变轻,神经元细胞死亡数量逐渐减少。与假手术组相比,模型组大鼠Longa评分、脑梗死面积、血清IL-6、TNF-α水平、小胶质细胞数目、蛋白IL-33、ST2L表达显著升高(P<0.05);与模型组相比,尼莫地平组、黄芩苷低、中、高剂量组大鼠Longa评分、脑梗死面积、血清IL-6、TNF-α水平、小胶质细胞数目、蛋白IL-33、ST2L表达显著降低,且呈剂量依赖性(P<0.05)。结论:黄芩苷对缺血性脑卒中大鼠具有神经保护作用,可能与IL-33/ST2L通路抑制有关。

Objective:To investigate effects of baicalin on neurological function and IL-33/interleukin-1 receptor-like 1(ST2L)signaling pathway in rats with ischemic stroke.Methods:Ninety rats were randomly divided into sham operation group,model group,nimodipine group[0.4 mg/(kg·d)],baicalin low,medium and high dose groups[50,100,150 mg/(kg·d)],modified Longa suture method was used to construct rat model of ischemic stroke.After 24 hours of modeling,Longa score was used to score the neurological deficits of rats;ELISA was used to detect serum IL-6 and TNF-αlevels in rats;2,3,5-triphenyltetrazolium chloride(TTC)staining was used to determine the area of cerebral infarction in rats;hematoxylin-eosin(HE)staining was used to detect pathological changes in brain tissue of rats;immunohistochemical method was used to detect the number of microglia in brain tissue of rats;Western blot was used to detect IL-33/ST2L pathway protein expression in brain tissue of rats.Results:In sham operation group,there was no edema in hippocampus of brain tissue of rats,the tissues were arranged clearly and the neuron cell structure was normal;rats in model group had severe edema in hippocampus,neuronal disorder,cell nucleus pyknosis and necrosis,and massive neuronal cell death;rats in nimodipine group,baicalin low,medium,and high dose groups had reduced edema,decreased neuronal cells,degeneration,and death.As the dose of baicalin increased,the degree of edema gradually became lighter,and the number of neuronal cell deaths gradually decreased.Compared with sham operation group,Longa score,cerebral infarction area,serum IL-6,TNF-αlevels,microglia number,protein IL-33 and ST2L expressions were significantly increased in model group(P<0.05);compared with model group,Longa score,cerebral infarction area,serum IL-6,TNF-αlevels,microglia number,protein IL-33,ST2L expressions in nimodi-pine group,baicalin low,medium and high dose groups were significantly decreased in a dose-dependent manner(P<0.05).Conclusion:Baicalin has a neuroprotective effect on rats with ischemic stroke,which may be related to the inhibition of IL-33/ST2L pathway.