发育期癫痫持续状态大鼠海马Semaphorins-3A与突触素P38的表达变化

Semaphorins 3A and synaptophysin P38 expression induced by status epilepticus in hippocampus of developing rat

目的观察发育期大鼠癫痫持续状态后海马内Semaphorins-3A、突触素P38的表达变化。方法生后7d（P7）、14d（P14）、21d（P21）、28d（P28）四个日龄组SD幼鼠共320只，每个日龄组大鼠按随机数字法分模型组（sE组）和生理盐水对照组（NS组）。用戊四氮（PTZ）诱导sE，免疫组化法观察sE发作后1d、7d、14d、21d、28d五个时间点海马CA1区Semaphorins-3A及突触素P38的表达。结果Semaphorins-3A阳性细胞在海马颗粒细胞层表达最明显，阳性表达量随大鼠生理日龄的增加呈减少趋势，尤以P7组表达最明显（如91552．68±4664．69）；不管大鼠日龄如何，sE发作后大鼠海马结构内Semaphorins-3A免疫反应产物的分布特征及表达与Ns组无明显变化，但是Semaphofins-3A表达量在sE后7d减少最明显（如56938．844-5688．47）。生理状态下P7组日龄大鼠P38表达在1～14d（5413．18±48．77，6223．40±29．19，6902．94±78．51）内存在逐渐增加的趋势，并在21d（7523．42±62．94）逐渐稳定。其他日龄组大鼠生理状态下P38表达相对平稳在同一水平上。P7、P14、P21和P28等各日龄组sE发作后1～28d的时间点上海马CA1区P38免疫反应产物的IOD值较NS组增加（P〈0．05），其中均以sE发作后14d（如8408．35±55．73）增加达最高峰。结论Semaphorins．3A和突触素P38参与了发育期及癫痫持续状态下大鼠海马突触可塑性变化。

Objective To observe Semaphorins-3A and synaptophysin P38 expression in hippocampus of developing rat induced by status epilepticus. Methods 320 SD rats were divided into four groups （P7,P14,P21 and P28 ） according to day -old after birth （7d, 14d, 21d and 28d）. Rats in each group were randomly divided into model group （SE group） and saline control group （NS group）. SE was induced by Pentylenetetrazol （PTZ）. Semaphorins-3A and synaptophysin P38 expression were determined by immunohistochemical staining on 1d, 7d, 14d, 21d and 28d after SE in hippocampal CA1 of rats. Results Semaphorins-3A-positive cells could be seen in the hippocampal granule cell layer in all rats. Semaphorins-3A expression tended to decrease with the increasing of day-age, especially in P7 group（91 552.68 ± 4664.69 ）. No matter how day-age, Semaphorins-3A expression was similar to that in NS group and was obvious reduced in 7d after SE（56 938.84 ± 5688.47 ）. Meanwhile P38 expression in P7-day-age rats had had been gradually increasing between l day and 14d （5413.18 ± 48.77,6223.40 ±29.19,6902.94±78.51 ）and then stabilized gradually on 21d（7523.42±62.94） after rats were tested. P38 expression in other day-age rat was relatively stable on the same level in physiological state. On the other hand P38 expression in the hippocampal CA1 region of P7 ,P14 ,P21 and P28 rats was significantly higher than that in normal rats between lday and 28day after SE episode（P〈 0.05） ,and reached a peak on 14 day（8408.35 ±55.73）. Con dusion Semaphorins-3A and synaptophysin P38 involved in hippocampal synaptic plasticity of rat in developing stage and epilepsy.