新生期大鼠反复痫性发作的远期后果

Long-term effects of pilocarpine-induced recurrent seizures on neonatal rats.

【目的】探讨反复新生期大鼠痫性发作对大鼠青春期及成年后细胞形态学和行为的影响。【方法】生后1 d的Wistar大鼠46只,随机分为惊厥组Ⅰ、Ⅱ各15只,对照组Ⅰ、Ⅱ各8只,惊厥组新生鼠在生后1d(P1)、生后4d(P4)、生后7d(P7)给予腹腔注射匹罗卡品,制备新生鼠癫痫模型,对照组腹腔注射生理盐水。在P35,P52通过Morris水迷宫测试大鼠空间学习记忆能力,在P60时惊厥组Ⅰ和对照组Ⅰ进行发作易感性测定,惊厥组Ⅱ和对照组Ⅱ进行尼氏染色和Timm染色观察有无神经元丢失及苔藓纤维发芽的情况。【结果】P35时Morris水迷宫测试中惊厥组到达平台的时间均显著慢于对照组,但在P52时只有测试的第1 d和第2 d两组差异有显著性。惊厥组Ⅰ和对照组Ⅰ经戊四唑诱发后均出现惊厥发作,惊厥组发作易感性明显高于对照组[出现全身性阵挛发作的平均潜伏期在惊厥组为(1 030±40)秒,对照组为(1 320±80)秒,t=3.4500,P<0.01]。惊厥组Ⅱ大鼠未见明显的神经元丢失。惊厥组Ⅱ大鼠CA3区及颗粒细胞上层的Timm染色记分与对照组Ⅱ相比明显增多(P<0.05)。【结论】新生期大鼠反复痫性发作会对大鼠细胞形态学、认知及发作易感性等方面产生远期的损害。

[Objective] To determine the effects of recurrent pilocarpine-induced seizures in neonatal rats on morphology and behavior when the animals were in adolescence and adulthood. [Methods] 46 neonatal Wistar rats were randomly divided into seizure group Ⅰ 、 Ⅱ（each group n= 15） and control group Ⅰ 、Ⅱ （each group n=8）. On Pl, P4, P7 rats were given intraperitoneal injections of pilocarpine to induce seizures. Neonatal rats of the control group were given saline injection （i. p） at the same time point. At P35 and P52 all rats were tested for spatial memory by Morris water maze task. At P60 rats of seizure group Ⅰ and control group Ⅰ were tested for seizure susceptibility by pentylenetetrazol （PTZ）. And brains of seizure groupⅡ and control group Ⅱ were examined for neuronal loss by Nissl staning and mossy fiber sprouting by Timm staining in the supragranular zone and CA3 pyramidal cell layers of the hippocampus. [Results] In Morris water maze task pilocarpine-treated rats were significantly slower than those of control rats on each of the six testing days at P35, while the difference was significant only on the first and second day of testing at P52. PTZ elicited seizures in all rats. But seizure susceptibility of pilocarpine-treated rats significantly increased compared with control rats（P〈0.05）. Pilocarpine-treated rats exhibited more Timm staining in the CA3 subfield and supragranular zone without obvious neuronal loss. [Conclusion] These findings indicate that pilocarpine-induced recurrent seizures in neonatal rats have long-term detrimental effects on morphology, cognition and seizure susceptibility.