惊厥易感大鼠听源性惊厥后脑内c-fos蛋白表达

cfos PROTEIN EXPRESSION AFTER AUDIOGENIC SEIZURES IN EPILEPSYPRONE RATS

目的：探讨遗传性癫痫易感大鼠Ｐ７７ＰＭＣ听源性惊厥的神经回路。方法：Ｐ７７ＰＭＣ大鼠以标准化听刺激（１２０ｄＢ，持续６０ｓ）诱发Ⅴ级听源性惊厥，分别在惊厥后０．５、１、２、４、２４ｈ断头、取脑切片，行Ｆｏｓ免疫组化染色观察。结果：惊厥后脑内Ｆｏｓ样免疫染色强度呈明显的时间依赖和区域特点。多数核团在惊厥后０．５～１ｈ开始出现Ｆｏｓ表达，２～４ｈ达高峰，２４ｈ明显回落，不同核团其时程也存在差异，Ｆｏｓ表达最先出现在下丘平面尾侧听通道核团、中央灰质、前庭神经核，继而出现在下丘、脑桥网状结构、皮层下结构、边缘系统、额顶新皮层区、梨状皮质。脑干听通道核团及脑桥网状结构、额顶新皮层区、梨状皮质Ｆｏｓ样免疫染色最强。结论：Ｐ７７ＰＭＣ大鼠听源性惊厥可引起脑内Ｆｏｓ区域性、快速、一过性表达升高。脑干听通道、脑桥网状结构、额顶新皮层区。

ABSTRACT Objective: To study audiogenic seizure pathway in epilepsyprone rats-P77PMC rats. Methods: 15 P77PMC rats induced to Ⅴ degree audiogenic seizures by standardized stimulus (120 dB, lasting 60 seconds), were randomized into 5 groups with 3 rats in each group and decapitated 0.5, 1, 2, 4, and 24 hours after seizures respectively, and cfos protein (Fos) was examined by immunohistochemically staining in brain sections (10 μm each) mounted on slides. Results: Foslike reactions were different in different regions and varied with time course after seizures. Positive reaction emerged 0.5-1 hour, reached a maximum 2-4 hours and decreased significantly 24 hours after seizures in most positive nuclei, but time courses differences also existed among nuclei. Foslike reactions were first seen in auditory nuclei caudal to inferior colliculus, central gray, vestibular nuclei and then, inferior colliculus, pontine reticular nuclei, subcortical structure, limbic structure, frontoparietal neocortex, and piriform cortex. The most intensive positive reactions were observed in brain stem auditory nuclei, pontine reticular nuclei, frontoparietal neocortex and piriform cortex. Conclusion: In P77PMC rats, a single audiogenic seizure induced rapid, transient, region and time dependent Fos expression in the brain. These results suggested that brain stem auditory nuclei, pontine reticular nuclei, frontoparietal neocortex, piriform cortex probably were important nuclei in P77PMC rat audiogenic seizure pathway.