促红细胞生成素对缺氧缺血性脑损伤大鼠的脑保护作用及机制

摘要

目的 观察促红细胞生成素(EPO)对缺氧缺血性脑损伤(HIBD)大鼠的脑保护作用并探讨其机制. 方法 选取7日龄Wistar新生大鼠120只,随机分为假手术组(对照组)、HIBD组、EPO治疗组各40只. EPO治疗组在HIBD模型建立后按5 000 IU/kg的剂量腹腔注射EPO,HIBD组注射等体积生理盐水. 各组分别在6、12、24、48、72 h各处死8只大鼠,分别采用Real-time PCR法、Western blotting法检测脑组织中Fas及FasL mRNA、蛋白表达.结果 HIBD组Fas mRNA在6 h后开始上升,12 h达最大值,24 h后开始下降,EPO治疗组在对应时间点Fas mRNA的相对表达量均低于HIBD组,且在12、24、48 h三个时点两组间的差别有统计学意义(P均<0.05);FasL mRNA相对表达量在6~24 h显著上升且在第24小时达最大值,之后开始下降,EPO治疗组FasL mRNA水平在6、12、24、48 h均显著低于HIBD组(P均<0.05). 对照组Fas和FasL蛋白维持在较低的基础水平,HIBD组Fas及FasL蛋白均有一个先升后降的明显变化趋势,EPO治疗组Fas及FasL蛋白表达明显减少,Fas蛋白在24、48 h及FasL蛋白在所有时点与HIBD组比较,P均<0.05. 结论 EPO能明显减缓HIBD对脑组织神经元的伤害,起到有效保护作用;其机制可能是通过下调HIBD脑组织中的Fas/FasL信号通路,抑制神经元细胞的凋亡.%Objective To observe the protective effect of erythropoietin (EPO) on rats with hypoxic-ischemic brain injury (HIBD) and to explore its mechanism.Methods A total of 120 Wistar rats in 7-day-old were selected and randomly divided into three groups (n=40):sham operation group (control group), HIBD group and EPO treatment group.After HIBD model was established, EPO (5 000 IU/kg) was injected into rats of the EPO treatment group;while in the HIBD group, the equal vol-ume normal saline was injected.Rats were killed at 6, 12, 24, 48 and 72 h, 8 rats at each time point per group.Then the ex-pression levels of Fas/FasL mRNA and protein in the brain tissues were detected by real-time PCR and Western blotting, respec-tively.Results In HIBD group, Fas mRNA expression was observed at 6 h, increased rapidly and reached the peak at 12 h, then decreased after 24 h;in EPO treatment group, the expression of Fas mRNA was lower than that in HIBD group at each time point, and the difference was significant at time points of 12, 24 and 48 h (all P<0.05).Similarly, FasL mRNA was increased obviously from 6 h to 24 h, and reached the peak at 24 h, and then decreased gradually, the FasL mRNA level was significantly decreased in EPO treatment group as compared with that of the HIBD group at 6, 12, 24 and 48 h (all P<0.05).On the protein level, the Fas and FasL in the control group was very low;and there was a changing trend in the HIBD group , which rose first and then fell;the Fas protein expression at 24 and 48 h, and FasL protein expression at all the time points in the EPO treatment group was significantly decreased (all P<0.05).Conclusion EPO could alleviate the damage of HIBD on neurons in the brain tissue and have an effective protective effect , whose mechanism might be that the apoptosis of neuronal cells are inhibited through the down-regulation of Fas/FasL signal pathway in the HIBD brain tissues.