青藤碱对缺血再灌注大鼠脑保护的作用机制

Effect mechanism of neuroprotection of Sinomenine on rats with cerebral ischemia-reperfusion

目的探讨青藤碱(Sin)对缺血再灌注(IR)大鼠脑保护的作用机制。方法80只Wistar大鼠随机分为假手术组、IR组、Sin高剂量(60mg/kg)组和Sin低剂量(30mg/kg)组;Sin高剂量组和Sin低剂量组分别腹腔注射相应剂量Sin;30min后线栓法制备局灶性IR模型;IR后24h,应用2,3,5-三苯基氯化四氮唑(TTC)和HE染色观察脑梗死体积及脑组织病理学变化;干湿重法检测脑含水量;免疫组化法检测各组大鼠额顶部皮质核转录因子(NF)-κBp65、细胞间黏附分子(ICAM)-1表达及髓过氧化物酶(MPO)活性。结果与IR组比较,Sin预处理后脑组织病理学改变明显减轻,Sin高剂量组缺血性改变更轻;Sin高、低剂量组脑梗死体积明显缩小,脑含水量明显降低,且Sin高剂量组更明显(均P<0.05)。假手术组皮质可见少量NF-κBp65表达于胞质,IR组、Sin高、低剂量组NF-κBp65表达增加(均P<0.05),且表达于胞核;与IR组比较,Sin高、低剂量组NF-κBp65核表达明显减少,Sin高剂量组减少更显著(均P<0.05)。IR组及Sin高、低剂量组MPO活性较假手术组明显增加(均P<0.05);与IR组比较,Sin高、低剂量组ICAM-1表达和MPO活性明显降低,Sin高剂量组降低更显著(均P<0.05)。结论Sin通过抑制脑组织NF-κBp65及ICAM-1表达和MPO活性,减轻IR后脑组织的炎症反应和脑水肿;其脑保护作用呈剂量依赖性。

Objective To study the effect mechanism of neuroprotection of Sinomenine （Sin） on rats with cerebral ischemia-reperfusion（IR）. Methods 80 Wistar rats were randomly divided into sham-operated group, IR group, Sin high-dose （ 60 mg/kg ） group and Sin low-dose （ 30 mg/kg ） group. The correlative dose of Sin were intraperitoneal injected in Sin high-dose and low-dose groups, respectively. 30 min later, the IR models were made. After 24 h of IR, the volume of cerebral infarction（CI） and the change of cerebral pathology were observed by TTC and HE staining. The brain water content was investigated by dry and wet weight method. The expression of nuclear factor （NF）-κBp65, intercellular adhesion molecule （ICAM）-1 and the activity of myeloperoxidase （MPO） in the frontal and parietal cortex were detected by immunohistochemistry. Results Compared with IR group, the ischemic impairment in Sin high and low-dose groups were obviously lighter, even lighter in Sin high-dose group; the CI volumes and brain water content were significantly reduced ; while, even lower in Sin high-dose group （ all P 〈 0. 05 ）. The expression of NF-κB p65 in sham-operated group was in cytoplasm and very little ; but in IR group, Sin high and low-dose groups were in nucleus and significantly increased （ all P 〈 0.05 ）. Compared with IR group, the expression of NF-κB p65 in Sin high and low-dose groups were obviously reduced and even lower in Sin high-dose group （ all P 〈0. 05）. Compared with sham-operated group, the activity of MPO in IR group, Sin high and low-dose groups were obviously increased （ all P 〈 0. 05 ）. The expression of ICAM-1 and the activity of MPO in Sin high and low-dose groups were obviously reduced than those in IR group, and even lower in Sin high-dose group （all P 〈 O. 05 ）. Conclusions Sin can restrain the expression of NF-κBp65, ICAM-1 and the activity of MPO, and then reduce cerebral inflammation and brain edema after IR; and this neuroprotective effect is dose-dependent.