亚硒酸钠对沙土鼠脑缺血再灌注损伤后细胞凋亡及谷胱甘肽过氧化物酶的影响

Effects of sodium selenite on apoptosis and glutathione peroxidase in gerbils following cerebral ischemic reperfusion injury

目的:观察亚硒酸钠对沙土鼠脑缺血再灌注损伤的保护作用并分析其机制。方法:实验于2002-02/2003-04在泰山医学院机能实验室完成。将40只沙土鼠随机分为5组,假手术组,缺血再灌注2,4d组,亚硒酸钠处理-缺血再灌注2,4d组,各8只。假手术组及缺血再灌注2,4d组自由饮用自来水,亚硒酸钠处理-缺血再灌2,4d组自由饮用0.8mmol/L亚硒酸钠水1个月。采用夹闭双侧颈动脉法制备沙土鼠脑缺血再灌注模型,假手术组除不夹闭颈总动脉外,其余操作相同。术后各组饮水情况同术前。原位末端转移酶标记法染色光镜下观察凋亡神经元情况,计算凋亡密度。同时测定脑组织中谷胱甘肽过氧化物酶的含量。结果:实验纳入沙土鼠40只,死亡2只,模型成功38只,模型成功率95%,后补充2只沙土鼠,40只动物进行结果分析。①光镜下原位末端转移酶标记法染色显示凋亡情况:假手术组凋亡神经元少见;缺血再灌注2,4d组凋亡神经元分布较广泛,4d时更明显;亚硒酸钠处理-缺血再灌注2,4d组凋亡神经元减少,4d时更少。②各组谷胱甘肽过氧化物酶及凋亡密度比较:亚硒酸钠处理-缺血再灌注2,4d组沙土鼠与缺血再灌注2,4d组比较,谷胱甘肽过氧化物酶含量增多[分别为(317.73±50.96),(319.62±63.14),(181.16±32.06),(185.99±31.92)nkat/L],凋亡细胞减少[分别为(44.6±3.2),(51.4±4.7),(60.8±2.5),(67.8±3.7)个],差异有显著性意义(P<0.01)。结论:①亚硒酸钠可增强脑缺血再灌注早期脑组织中谷胱甘肽过氧化物酶的活性,抑制氧自由基损伤,减轻脂质过氧化反应,从而减轻脑缺血再灌注损伤后神经元的坏死和凋亡,并可能存在对脑缺血耐受的预处理机制。②亚硒酸钠对沙土鼠脑缺血再灌注损伤具有保护作用。

AIM： To observe the protective effects and analyze the mechanisms of sodium selenite on cerebral ischemic reperfusion injury in gerbils. METHODS： The experiment was finished in the functional laboratory of Talisman Medical College from February 2002 to Jun 2003. Forty gerbils were randomly divided into five groups with 8 gerbils in each： shamoperated group, cerebral ischemic reperfusion group for 2 and 4 days, cerebral ischemic reperfusion for 2 and 4 days with sodium serenity-treated group. Sham-operated group and cerebral ischemic reperfusion groups for 2 and 4 days were fed with tap water freely, and the cerebral ischemic reperfusion for 2 and 4 days with sodium serenity-treated groups were fed with 0.8 mmol/L water of sodium selenite freely for a month, Cerebral ischemic reperfusion models were made by means of clipping bilateral common carotid arteries after five minutes in the others groups, but not in the sham-operated group, which other operations were alike. The postoperative conditions for drinking water were the same as the preoperative ones. Apeptosis of hippecampus was observed by light microscope by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL）, the number of apoptosis cells was counted and density was calculated. The contents of glutathione peroxidase （GSH-Px） in cerebral tissue were measured. RESULTS： Forty gerbils were used, 2 of them died, and 38 were made into models successfully, the successful rate was 95%, finally 40 gerbils were involved in the analysis of results after 2 gerbils were supplemented. ①The results of TUNEL under light microscope showed that few apoptotic neurons were observed in the sham-operated group, the apoptotic neurons distributed extensively in the cerebral ischemic reperfusion group for 2 and 4 days of which was more for 4 days; the apoptotic neurons were decreased in the cerebral ischemic reperfusion for 2 and 4 days with sodium serenitytreated groups of which was lower for 4 days. ② Comparison of GSH-Px and apoptosis density： The contents of GSH-Px were higher [（317.73 ±50.96）, （319.62±63.14）, （181.16±32.196）, （185.99±31.92） nkat/L], and the number of apoptosis cells was lower [（44.6±3.2）, （51.4±4.7）, （60.8±2.5）, （67.8 ±3.7） cells] in the selenite-treated groups than in the ischemie reperfusion groups, and there was significant difference （P 〈 0.01）. CONCLUSION： ① Sodium selenite could enhance the activity of GSH-Px in early cerebral tissue of ischemic reperfusion, inhibit the damage of oxygen-derived free radical and extenuate lipid peroxidation so that itcould reduce death and apoptosis of neuron after cerebral ischemic reperfusion injury, precondition cerebral ischemia tolerance.②Sodium selenite could protect neuron against cerebral ischemic reperfusion injury.