香芹酚预处理对脑缺血再灌注大鼠血脑屏障的保护作用

Protective effects of carvacrol pretreatment on blood-brain barrier in rats with cerebral ischemia/reperfusion

目的探讨香芹酚预处理对脑缺血/再灌注损伤的防护作用及对血脑屏障的影响。方法SD大鼠随机分为假手术组、模型组、香芹酚低剂量组(50 mg/kg)、香芹酚高剂量组(100 mg/kg)、阳性对照组(依达拉奉10 mg/kg),于造模前1周开始腹腔注射给药;线栓法建立大脑中动脉栓塞(middle cerebral artery occlusion,MCAO)大鼠模型,缺血60 min再灌注24 h,采用Zea Longa法测评大鼠神经功能,伊文思蓝(EB)渗漏法评估血脑屏障通透性,免疫印迹(Western blot)法检测脑缺血半暗带胞质附着蛋白1(zonula occludens-1,ZO-1)、闭锁蛋白(occludin)表达,实时聚合酶链式反应(RT-PCR)检测脑缺血半暗带基质金属蛋白酶2(matrix metalloproteinase-2,MMP-2)、MMP-9的基因表达。结果模型组MCAO大鼠均存在程度较重的神经功能障碍,香芹酚高、低剂量组大鼠神经功能评分显著降低,差异有统计学意义(P<0.05);与模型组相比,香芹酚高、低剂量组缺血侧脑组织EB渗漏量显著减少,差异有统计学意义(P<0.05),血脑屏障紧密连接蛋白ZO-1、occludin表达明显增高,差异有统计学意义(P<0.05),脑缺血半暗带MMP-2、MMP-9相对基因表达量明显降低,差异有统计学意义(P<0.01)。结论香芹酚预处理通过抑制脑组织MMP-2、MMP-9异常表达,维持血脑屏障结构的完整性,减轻脑缺血/再灌注损伤。

Objective To investigate the protective effects of carvacrol pretreatment on cerebral ischemia/reperfusion injury(CI/RI)in rats and its effects on blood-brain barrier.Methods SD rats were divided randomly into sham,model,low dose of carvacrol(50 mg/kg),high dose of carvacrol(100 mg/kg)and positive control(edaravone 10 mg/kg)groups.Drugs were administered by intraperitoneal injection for 1 week before the model operation.Middle cerebral artery occlusion(MCAO)model was established by the line-bolus method,and the rats were ischemic for 60 min and then reperfused for 24 h.After the reperfusion,the neurological function of MCAO rats was measured by the Zea Longa method,blood-brain barrier permeability was evaluated by evans blue(EB)leakage method,the expression of zonula occludens-1(ZO-1)and occludin in the cortical semidarkness zone were detected by Western blot method,and the the relative gene expression of MMP-2 and MMP-9 in the cortical semidarkness zone were examined by RT-PCR.Results MCAO rats in the model group all had a higher degree of neurological dysfunction.Compared with the model group,high and low doses of carvacrol significantly reduced the neurological function scores of MCAO rats(P<0.05),evidently reduced the volume of cerebral infarction(P<0.05),significantly reduced the EB leakage from the ischemic side of the brain tissue(P<0.05),significantly increased the expression of the blood-brain barrier tight junction proteins,ZO-1 and occludin(P<0.05),and significantly reduced the relative gene expression of MMP-2 and MMP-9 in the cortical semidarkness zone(P<0.01).Conclusion Carvacrylol pretreatment maintains the structural integrity of the blood-brain barrier and attenuates CI/RI by inhibiting the expression of MMP-2 and MMP-9.