磷酸二酯酶抑制剂对癫痫持续状态后未成熟脑认知功能的影响

Effects of Rolipram on cognitive impairments induced by epilepticus status in the immature brain

摘要:

目的：探讨磷酸二酯酶抑制剂咯利普兰（Rolipram）对癫痫持续状态（status epilepticus，SE）后未成熟脑认知功能的影响。方法：选取日龄21 d雄性SD幼鼠96只，按随机数字法分为正常对照（N+Veh）组、正常+Rolipram干预（N+Ro）组、SE对照（SE+Veh）组、SE+Rolipram干预（SE+Ro）组，其中SE组采用氯化锂-匹罗卡品建立癫痫持续状态模型；Rolipram干预组给予Rolipram 0.03 mg/kg腹腔注射，连续２周；对照组予含5%DMSO的生理盐水。采用水迷宫和避暗实验检测大鼠的认知功能，神经电生理水平采用膜片钳技术记录海马脑片长时程增强（long-term potentiation，LTP）变化，蛋白免疫印迹方法检测海马内磷酸化的环磷酸腺苷反应元件结合蛋白（phosphorylated cAMP response element binding protein，pCREB）水平的变化情况。结果：SE后２周，SE+Veh组与N+Veh组相比较水迷宫定位航行实验中寻台潜伏期延长（第3天和第4天分别为：P<0.01；P<0.05）；探查实验在目标象限探索时间缩短（P<0.01），跨平台次数减少（P<0.05）；避暗实验逃避潜伏期缩短（P<0.001）；LTP中高频刺激后30 min 场兴奋性突触后电位（field excitatory postsynaptic potential，fEPSP）斜率比值减小（P<0.05）；海马pCREB表达量下降（P<0.01）。Rolipram处理后，SE+Veh组与SE+Ro组相比较在水迷宫定位航行实验中寻台潜伏期缩短（第4天，P<0.05）；探查实验在目标象限探索时间延长（P<0.05），跨平台次数增加（P<0.05）；避暗实验逃避潜伏期延长（P<0.01）；LTP高频刺激后30 min的fEPSP斜率比值增大（P<0.01）；海马pCREB表达量升高（P<0.01）。结论：Rolipram能改善SE所致的认知功能障碍，其机制可能与增加pCREB的表达量有关。

Abstract:

Objective：To explore the effects of Rolipram on cognitive impairments induced by epilepticus status in the immature brain. Methods：Ninety six P21 SD male rats were randomly divided into four groups：N+Vehicle（N+Veh），N+Rolipram（N+Ro），SE+Vehicle（SE+Veh） and SE+Rolipram（SE+Ro）. Licl-Pilo was used to build the SE model. The animals received vehicle（5% DMSO） or Rolipram（0.03 mg/kg） once a day（ip） for two week. The cognitive functions were tested by Morris water maze，step-through test and hippocampus long-term potentiation；the phosphorylated cAMP response element binding protein（pCREB） levels were evaluated by Western blot. Results：Compared with those of （N+Vehicle） group，in the Morris water maze test，the（SE+vehicle） group’s escaping la－tency period was significantly longer（the third day and fourth day：P<0.01 and P<0.05）；the time in the target quadrant was longer in probe trail（P<0.01），cross-platform times were decreased（P<0.05）；in the step-through test，the（SE+vehicle） group’s escape latency was shorter（P<0.001）；the slop of fEPSP in hippocampus long-term potentiation was reduced at 30 min after HFS（P<0.05）；in Western blot test，pCREB levels were decreased（P<0.001）；and all of these were rescued with Rolipram treatment. Compared with those of （SE+Vehicle） group，in the Morris water maze test，the（SE+Rolipram） group’s escaping latency period was significantly shorter（the fourth day：P<0.05）；the time in the target quad－rant was shorter in probe trail（P<0.05），cross-platform times were increase（P<0.05）；in the step-through test，the（SE+Rolipram） group’s escape latency was longer（P<0.01）；the slop of fEPSP in hippocampus long-term potentiation was increased at 30min after HFS（P<0.01）；in Western blot，pCREB levels were in－creased（P<0.01）. Conclusion：These results indicate that the PDE4 inhibitor rolipram rescues cognitive impairments after SE，and this may be mediated through increased pCREB levels.