槐定碱对大鼠海马组织CA1区ERK信号转导通路的影响

Effect of Sophoridine on the ERK Signal Transduction Pathway of Hippocampal Cell in Rats

目的:观察槐定碱(sophoridine,SRI)对大鼠海马组织CA1区ERK信号转导通路的影响。方法:成年雄性SD大鼠72只随机分为生理盐水对照组(n=8),槐定碱组(n=32),PD98059+槐定碱组(n=32)。腹腔注射大剂量槐定碱(47.83mg/kg)建立癫痫模型,应用免疫组化法和Western blot法检测各组大鼠致痫后0.5h、1.5h、5.0h、8.0h海马组织CA1区ERK1、ERK2和p-ERK1/2的免疫阳性神经元数量的变化。结果:免疫组化结果显示生理盐水对照组大鼠海马CA1区有少量的ERK1和ERK2表达,p-ERK1/2仅在胞浆内表达弱阳性,槐定碱致痫0.5h后P-ERK1/2表达迅速增强,在神经元的胞核胞浆内都有表达;同时ERK1和ERK2阳性神经元数量明显多于生理盐水对照组(P<0.05),尤以致痫1.5h后该三种蛋白阳性细胞数量达到最高,5.0h时阳性神经元数量回降,8.0h继续回降,但仍高于生理盐水对照组。经PD98059干预后,槐定碱致痫大鼠海马ERK1、ERK2和P-ERK1,2阳性神经元数量明显低于槐定碱组(P<0.05)。Western blot检测显示痫性发作各时间点大鼠海马组织内ERK1、ERK2和p-ERK1/2蛋白表达较生理盐水对照组显著增多(P<0.05),其中1.5h点组的蛋白表达水平高于其他各时间点组。PD98059+槐定碱组与槐定碱组比较三种蛋白含量明显降低(P<0.05)。结论:槐定碱通过ERK信号通路对大鼠海马组织造成痫性损害。

Objectives：To explore effect of sophoridine on the ERK signal transduction pathway of CA1 region of hippocampus in rats.Methods：Seventy two adult male SD rats were randomly divided into saline control group（n=8）,sophoridin（SRI）group（n=32）and MEK1 inhibitor PD98059＋SRI group（n=32）.SRI was injected into the abdominal cavity of rats to establish epileptic rats model,using immunohistochemistry staining and western blot methods at 0.5h,1.5h,5.0h and 8.0h respectively after seizures.We evaluate the changes of ERK1,ERK2 and p-ERK1/2 protein expression in hippocampus.Results：Slight immunoreactivity of ERK1 and ERK2 was detected in hippocampal CA1 of normal rats,and weak imunoreactivity of P-ERK1/2 was observed only in neuronic intracytoplasm of NS groups.Strong immunoreactivity of p-ERK1/2was detected in hyippocampal neurons of SRI-treated rats at 0.5 h after SRI injection.In addition,both ERK1 and ERK2 began increasing at 0.5h group（P〈0.05）,reached the highest level at 1.5h,declined at 5.0h after SRI injection,and descended to the lower level at 8.0h.ERK expression was inhibited markedly in PD98059＋SRI group,and lower than that of SRI groups（P〈0.05）.Results of western blot suggested that ERK1,ERK2 and P-ERK1/2in the hippocampus of epileptic rats increased markedly as compared with the control rats（P〈0.05）at different time groups.The expression of all three proteins was higher in 1.5h group than in the other groups.The three proteins decreased to some extent in PD98059＋SRI group.Conclusions：Sophoridine could induce hippocampal neurons from being damaged by epileptic seizures,partially the ERK signaling pathway in vivo.