N-乙酰半胱氨酸对大鼠局部脑缺血再灌注损伤的保护作用

Protective effect of N-acetylcysteine on focal cerebral ischemia-reperfusion injury in rat

目的:观察预先应用抗氧化剂N-乙酰半胱氨酸对局部脑缺血再灌注损伤的保护作用,以及在此过程中核转录因子κB表达的变化。方法:实验于2003-08/2004-04在哈尔滨医科大学动物实验中心及病理实验室完成。①取63只雄性Wistar大鼠随机分为3组:假手术组(n=7),模型组(n=28)和N-乙酰半胱氨酸组(n=28),后两组又分为缺血6,24h两个亚组,每亚组14只。②N-乙酰半胱氨酸组于缺血前30min腹腔注射N-乙酰半胱氨酸(150mg/kg),其余大鼠注射等体积生理盐水。模型组和N-乙酰半胱氨酸组大鼠采用线栓法制作大鼠局灶脑缺血再灌注模型,于缺血6或24h后给予再灌注,1h后断头处死;假手术组不栓塞大脑中动脉,于术后1h断头处死。③应用红四氯氮唑染色测定大鼠脑梗死体积,苏木精-伊红染色分析病理形态学变化,免疫组化法观测核转录因子κB的表达情况。结果:经补充后63只大鼠进入结果分析。①N-乙酰半胱氨酸组较模型组脑组织损伤轻,炎性细胞浸润少。②缺血6,24hN-乙酰半胱氨酸组梗死体积百分比低于相应模型组[(8.57±2.34)%,(15.56±3.46)%;(23.66±6.34)%,(31.91±3.30)%;P<0.01]。③假手术组核转录因子κBp65主要存在于胞质,模型组明显从胞质移位于胞核,N-乙酰半胱氨酸组较模型组p65阳性细胞减少(P<0.01)。结论:①缺血再灌注后核转录因子κBp65活化,从胞质转移到胞核。②应用N-乙酰半胱氨酸能抑制核转录因子κB活化,减少炎症反应和脑组织损伤,缩小梗死体积,在6,24h的长时间脑缺血中仍能起到脑保护作用。

AIM： To observe the protective effect of antioxidant pretreatment of N- acetylcysteine on focal cerebral ischemia-reperfusion injury and changes of the expression of nuclear transcription factor kappa B （NF-κB）. METHODS： From September 2004 to January 2005, the study was performed in the Experimental Center and Pathological Laboratory of Harbin Medical University. ① Sixty-three male Wistar rats were randomly divided into 3 groups： sham-operated group （n=7）, model group （n=28） and N-acetylcysteine group （n=28）, and the latter two groups were divided into ischmia for 6 and 24 hours subgroups respectively with 14 rats in each. ② The rats in the N-acetylcysteine group were given intraperitoneal injection of N-acetylcysteine （150 mg/kg） at 30 minutes before ischemia, and the other rats were injected with saline of the same volume. Rats in the model group and N-acetylcysteine group were made into models of focal cerebral ischemia-reperfusion with thread occlusion, and then reperfused at 6 or 24 hours after ischemia, and then they were killed after 1 hour. Rats in the sham-operated group were not treated with middle cerebral artery occlusion, and killed at 1 hour postoperatively by cutting down head. ③ The cerebral infarcted volume was detected with red tetrazoline staining, the pathomorphological changes were analyzed with haematine-eosin staining, and the expression of NF-κB was observed and determined with immunohistochemical method. RESULTS： Finally 63 rats were involved in the analysis of results after complement. ① Compared with the model group, the injury of brain tissue was mild and inflammatory cells were fewer in the N-acetylcysteine group. ② The percentages of infarcted volume at 6 and 24 hours after ischemia in the N-acetylcysteine group were lower than those in the model group [（8.57±2.34）%, （15.56±3.46）%; （23.66±6.34）%, （31.91±3.30）%; P 〈 0.01]. ③ The translocation of NF-κB from cytoplasm to nucleus increased significantly after ischemia-reperfusion. The expression of NF-κB p65 decreased in the N-acetylcysteine group （P 〈 0.01）. CONCLUSION： ① The NF-κB p65 activation translocated from cytoplasm to nucleus. ②N-acetylcysteine could inhibit NF-κB activation, reduce inflammatory reaction and cerebral tissue damage. It might play an important role in the neuroprotective agents in long-term ischemia for 6 and 24 hours.