榄香烯调节大鼠脑缺血再灌注慢性损伤的保护作用及相关机制

Elemene protects rats from chronic cerebral injury induced by ischemia/reperfusion and its mechanisms

目的探讨榄香烯对大鼠脑缺血再灌注慢性损伤的保护作用及相关机制。方法将48只SD大鼠采用随机数字表法分为榄香烯低剂量组(1 mg/kg)、榄香烯高剂量组(10 mg/kg)、假手术组和模型组。采用线栓法闭塞大脑中动脉90 min,再灌注14 d制作大鼠脑缺血再灌注模型。手术当天起连续给药14 d,然后进行神经功能缺损评分;采用TTC染色检测大鼠脑梗死体积;HE染色观察大鼠脑组织皮层神经元形态;原位末端标记法(TUNEL)染色检测神经元凋亡数;Western blot法检测B细胞瘤-2(Bcl-2)、半胱氨酸天冬氨酸蛋白酶-3(Caspase-3)、微管相关蛋白轻链3(LC3)-Ⅱ、LC3-Ⅰ、p62表达水平。结果与假手术组相比,模型组大鼠神经功能缺损评分明显升高(P<0.01);与模型组相比,榄香烯低剂量和高剂量组大鼠神经功能缺损评分均明显降低(均P<0.05)。与假手术组相比,模型组大鼠脑梗死体积明显增大(P<0.01);与模型组相比,榄香烯低剂量和高剂量组大鼠脑梗死体积均明显缩小(均P<0.05)。HE染色结果显示,除假手术组外,模型组、榄香烯低剂量组和榄香烯高剂量组大鼠脑组织皮层神经元均出现细胞核固缩、不规则,碎片化。与模型组相比,榄香烯低剂量组和榄香烯高剂量组大鼠脑组织皮层神经元细胞核畸形有所改善。TUNEL染色结果显示,与假手术组相比,模型组大鼠皮层神经元核固缩明显,呈碎片状、深棕色颗粒,神经元凋亡数明显增加(P<0.01);与模型组相比,榄香烯低剂量组和榄香烯高剂量组大鼠脑组织皮层神经元凋亡数均呈不同程度降低(均P<0.01)。与假手术组相比,模型组Bcl-2、p62表达水平均明显下调,Caspase-3表达水平、LC3-Ⅱ/LC3-Ⅰ比值均明显上调(均P<0.01);与模型组相比,榄香烯高剂量组Bcl-2表达水平明显上调,榄香烯高剂量和低剂量组caspase-3表达水平、LC3-Ⅱ/LC3-Ⅰ比值均明显下调,p62表达水平均明显上调(均P<0.01)。结论榄香烯改善大鼠脑缺血再灌注慢性损伤,可能是通过抑制皮层过度自噬和凋亡实现的。

Objective To investigate the effects of elemene on cerebral chronic injury after cerebral ischemia/reperfusion in rats and its mechanisms.Methods Forty-eight SD rats were randomly divided into model group,sham operation group,elemene low-dose group(1 mg/kg)and elemene high-dose group(10 mg/kg)with 12 rats in each group.Cerebral ischemia/reperfusion model was induced by thread-occlusion of middle cerebral artery for 90 min and reperfusion for 14 d in rats of model and elemene treatment groups.Elemene was continuously administrated from d1 to d14 of modeling in elemene treatment groups.After 14 days,the evaluation of neurological function scores was performed,the volume of cerebral infarction was determined by TTC staining,the morphology of cortical neurons was observed by HE staining,the neuron apoptosis was detected by TUNEL staining,the expression of apoptosis and autophagy-related proteins in cortical tissue was analyzed by Western blot.Results Compared with the model group,the neurological deficit scores of the elemene groups significantly decreased(P<0.05),the volume of cerebral infarction was significantly reduced(P<0.05),and the morphology and apoptosis of cortical neurons were improved(P<0.05),the expression level of Caspase-3 was significantly decreased(P<0.05),the expression level of Bcl-2 was increased(P<0.05),the ratio of microtubule-associated protein 1 light chain 3(LC3)-Ⅱto LC3-Ⅰ(P<0.05)was decreased,and the expression of p62 was up-regulated(P<0.05).Conclusion Elemene can protect rats fromchronic ischemia reperfusion injury,and this effect might be related to inhibiting excessive autophagy and apoptosis in the cortex of rats.