促红细胞生成素对缺氧缺血性脑损伤模型新生大鼠认知功能的影响及对相关PARP-1/AIF信号通路的调控机制研究

Effects of Erythropoietin on Cognitive Function of Neonatal Rats with Hypoxic-ischemic Brain Injury and Regulation Mechanism Study of PARP-1/AIF Signaling Pathway

目的:研究促红细胞生成素(EPO)对缺氧缺血性脑损伤(HIBI)模型新生大鼠认知功能的影响以及对相关聚腺苷二磷酸核糖聚合酶1(PARP-1)/凋亡诱导因子(AIF)信号通路的调控机制。方法:将SD新生大鼠随机分为假手术组(Sham组)、模型组(HIBI组)和EPO干预组(EPO组),每组22只。HIBI组和EPO组大鼠采用Rice法建立HIBI模型,Sham组大鼠切口后即缝合而不作缺氧缺血处理。造模完毕后,EPO组大鼠每天腹腔注射重组人促红素注射液5 000 IU/kg,连续给药14 d;Sham组和HIBI组大鼠则腹腔注射等容生理盐水。取大鼠脑组织,采用TTC染色法检测梗死情况;采用TUNEL法检测海马组织CA1区神经细胞凋亡情况;采用蛋白免疫印迹法检测海马组织CA1区中PARP-1、AIF、Bax蛋白表达水平;采用Morris水迷宫实验考察大鼠空间学习记忆能力。结果:与Sham组比较,HIBI组大鼠脑组织梗死面积比显著升高,海马组织CA1区中TUNEL阳性凋亡细胞数显著增多,PARP-1、AIF、Bax蛋白表达水平均显著升高;Morris水迷宫实验中大鼠的逃避潜伏期显著延长,穿台指数显著减少;上述差异均有统计学意义(P<0.05)。与HIBI组比较,EPO组大鼠脑组织梗死面积比显著降低,海马组织CA1区中TUNEL阳性凋亡细胞数显著减少,PARP-1、AIF、Bax蛋白表达水平均显著降低;Morris水迷宫实验中大鼠的逃避潜伏期显著缩短,穿台指数显著增加;上述差异均有统计学意义(P<0.05)。结论:EPO能够明显抑制HIBI引起的大鼠神经细胞凋亡而发挥脑组织保护作用,并能促进大鼠认知功能的恢复,这一作用很可能是通过抑制细胞凋亡PARP-1/AIF信号通路来实现的。

OBJECTIVE:To study the effects of erythropoietin(EPO)on cognitive function of neonatal rats with hypoxicischemic brain injury(HIBI),and the regulation mechanism of related PARP-1/AIF signaling pathway.METHODS:SD neonatal rats were randomly divided into sham operation group(Sham group),model group(HIBI group)and EPO intervention group(EPO group),with 22 rats in each group.HIBI model was induced by Rice method in HIBI group and EPO group,and rats in sham group received suturing after cutting without hypoxic-ischemic treatment.After modeling,rats in EPO group was given Erythropoietin injection intraperitoneally each day,5 000 IU/kg,for consecutive 14 d.Rats in Sham group and HIBI group were given constant volume of normal saline intraperitoneally.Cerebral tissue of rats was collected,and TTC staining was used to detect cerebral infraction.Neuronal apoptosis in hippocampal CA1 region was detected by TUNEL method.The expression of PARP-1,AIF and Bax protein in hippocampal CA1 region was detected by Western blot.Morris water maze was used to examine the spatial learning and memory abilities of rats.RESULTS:Compared with Sham group,the cerebral infarction area of rats in HIBI group was increased significantly;the number of TUNEL positive apoptosis cells in neuron of hippocampal CA1 region was increased significantly;the protein expression levels of PARP-1,AIF and Bax were increased significantly;in Morris water maze experiment,the escape latency of rats was prolonged significantly,while the index of crossing the platform was decreased significantly,with statistical significance(P<0.05).Compared with HIBI group,cerebral infraction area of rats in EPO group was decreased significantly;the number of TUNEL positive apoptosis cells in neuron of hippocampal CA1 region was decreased significantly;the protein expression levels of PARP-1,AIF and Bax were decreased significantly;in Morris water maze experiment,the escape latency of rats was shortened significantly,while the index of crossing the platform was increased significantly,with statistical significance(P<0.05).CONCLUSIONS:EPO can significantly inhibit HIBI-induced neuron apoptosis of rats so as to play protective effect on cerebral tissue,and promote the recovery of cognitive function,the mechanism of which may be associated with inhibiting apoptosis PARP-1/AIF signaling pathway.