李天富, 吕传真, 夏作理, 牛敬忠, 杨明峰, 罗玉敏, 洪震
泰山医学院附属医院神经内科. 山东, 泰安 271000；复旦大学华山医院神经内科. 上海 200040
应用红藻氨酸(kainic acid,KA)诱导的大鼠边缘叶发作癫痫模型,检测Bad(Bcl-2-associated death protein)、14-3-3、磷酸化Bad、Bcl-XL和Bcl-2在癫痫大鼠海马神经元的表达.单侧杏仁核内注射KA诱导癫痫发作,持续记录脑电和局部脑血流(regional cerebral blood flow,r-CBF),发作1 h后静脉注射30 mg/kg安定终止发作,然后分别用cresyl violet染色和TUNEL染色观察海马神经元存活和凋亡的变化;用免疫荧光、Western blot和免疫沉淀检测海马Bad、14-3-3、磷酸化Bad、Bcl-XL和Bcl-2的表达.结果表明,发作终止8 h时出现TUNEL阳性细胞,24 h时达高峰;发作诱导Bad去磷酸化,去磷酸化的Bad与分子伴侣蛋白14-3-3解离,然后Bad与Bcl-XL结合;磷酸化Bad表达减少而Bcl-2表达增加;发作前后r-CBF无明显变化.以上结果提示,癫痫发作诱导Bad的去磷酸化和Bcl-2表达上调,Bad的去磷酸化可能具有损伤作用,而Bcl-2的表达上调则对癫痫神经元损伤具有保护作用,但与脑缺血无关。
Dephosphorelation of Bad and upregulation of Bcl-2 in hippocampus of rats following limbic seizure induced by kainic acid injection into amygdaloid nucleus
Li Tianfu, Lu Chuanzhen, Xia Zuoli, Niu Jingzhong, Yang Mingfeng, Luo Yumin, Hong Zhen
Department of Neurology, Affiliated Hospital of Taishan Medical College. Taian 271000, Shandong, China；Department of Neurology, Huashan Hospital, Fudan University. Shanghai 200040, China
The purpose of the present study was to explore the seizure-induced changes in Bad (Bcl-2-associated death protein), 14-3-3, phosphoBad, Bcl-2 and Bcl-XL expression in the rat model of focal limbic seizure. Unilateral intra-amygdaloid injection of kainic acid (KA) was made to induce seizure. Electroencephalogram (EEG) and regional cerebral flow (r-CBF) were monitored continuously. Diazepam (30 mg/kg) was administered to terminate the seizure. The apoptotic and surviving neurons in the hippocampus were observed by terminal deoxynucleotidyl transferrase-mediated dUTP nick end labeling (TUNEL) and cresyl violet staining, the expression of Bad, 14-3-3, phosphoBad, Bcl-2 and Bcl-XL were detected with immunofluoresence, Western blot and immunoprecipitation. The results showed that TUNEL-positive neurons appeared at 8 h and reached maximum at 24 h following seizure cessation within the ipsilateral CA3 subfield of the hippocampus. Seizure induced the dephosphorylation of Bad and the dissociation of Bad from its chaperone protein 14-3-3 and subsequent dimerization of Bad with Bcl-XL. The expression of phosphoBad decreased and Bcl-2 increased. There was little change in r-CBF after the seizure. These results suggest that seizure leads to a dephosphorylation of Bad and an upregulation of Bcl-2. Dephosphorylation of Bad may be injurious while the upregulation of Bcl-2 may be protective to the brain damage induced by seizures, but not related with r-CBF.
Key words: Kainic acid;;;;;;;;
李天富, 吕传真, 夏作理, 牛敬忠, 杨明峰, 罗玉敏, 洪震. 杏仁核注射红藻氨酸诱导的边缘叶发作癫痫大鼠海马 Bad去磷酸化和Bcl-2表达上调[J]. 生理学报 2005; 57 (3): .
Li Tianfu, Lu Chuanzhen, Xia Zuoli, Niu Jingzhong, Yang Mingfeng, Luo Yumin, Hong Zhen. Dephosphorelation of Bad and upregulation of Bcl-2 in hippocampus of rats following limbic seizure induced by kainic acid injection into amygdaloid nucleus. Acta Physiol Sin 2005; 57 (3): (in Chinese with English abstract).