胶质细胞源性神经营养因子在大鼠急性痫性发作中的表达

Time course expression of GDNF protein in rat hippocampus after intrahippocampal kainic acid injection induced acute seizure

目的 动态观察胶质细胞源性神经营养因子 (GDNF)蛋白在红藻氨酸 (KA)诱导的大鼠急性痫性发作中的表达水平 ,探讨 GDNF在急性癫痫发作中的作用。方法 成年 SD大鼠随机分为 NS对照组和 KA处理组。急性痫性发作经单侧海马内注入 KA(0 .6 μg/0 .3μl)诱导。两组大鼠分别在注射后第 3、6、2 4h和第 4、7d,采用免疫细胞化学方法检测 GDNF蛋白在海马中的表达水平。结果 NS组海马 GDNF表达极微量 ,各时间点均在基线水平。KA组在注射后 3h GDNF少量增高 ,6 h达高峰 ,并持续至第 4d,均高于各时间点 NS组 (P <0 .0 5 ) ,至第 7d回复正常水平 (P >0 .0 5 )。双侧 GDNF表达在各时间点无显著差异。结论 单侧海马内注射 KA诱导的大鼠急性痫性发作可导致双侧海马齿状回和门区 GDNF蛋白表达增高 ,GDNF可能参与拮抗 KA神经兴奋性毒性作用 。

Objective To examine the expression of glial cell line derived neurotrophic factor(GDNF)protein in hippocampus of acute epileptic SD rats. Method Forty Sprague Dawley rats were randomly divided into two groups: normal control (Group NS) and kainic acid treated (Group KA). The models were induced by unilateral intrahippocampal injection of KA(0.6μg/0.3μl). GDNF were examined with immunocolloidal gold silver staining (IGSS) dynamically at post injection hours 3, 6 and 24; and post injection days 4 and 7 in both groups. The density of IGSS staining were analyzed using an imaging analysis system. Results In group NS, GDNF immunoreactivity was very weak, and remained at the normal level at each time point. In group KA, GDNF protein began to increase bilaterally in the dentate gyri and hilar area within 3h after KA injection, reached its maximum level at 6h, then decreased at 24h and PID 4, these were higher than the corresponding control(P<0.05), and returned to the control level by PID 7. No significant difference was found in GDNF between bilateral dentate gyri at each time point. Conclusion GDNF can be increasingly expressed in the dentate gyri and hilar areas after KA induced seizures, and may protect the dentate granule cells from KA excitatory toxicity.