海人酸致痫大鼠海马神经元凋亡研究

A Study of Neuronal Apoptosis in Rat Hippocampus after Kainic Acid-evoked Seizures

目的 研究大鼠癫痫发作后海马神经元凋亡的时空分布。方法 采用海人酸 (KA)诱导大鼠癫痫模型 ,以原位末端标记 (TUNEL)及透射电镜检测癫痫发作后 6h、1d、3d、7d海马神经元凋亡。结果 对照组及KA致痫后 6h组 ,海马区均未发现凋亡细胞。KA致痫后 1d ,海马CA1、CA3及CA4区开始出现凋亡细胞 ,3d时明显增多 ,7d时最多。KA致痫后 1d、3d、7d ,海马CA1锥体层线性长度1mm的TUNEL阳性细胞数分别为 (6 .6 0± 3.6 9)个、(13.5 7± 5 .17)个和 (2 5 .96± 4 .87)个 ;CA3区分别为 (6 .4 8± 2 .4 5 )个、(13.89± 2 .5 2 )个和 (2 8.80± 5 .39)个 ;CA4区分别为 (4 .6 0± 1.4 5 )个、(12 .2 0± 2 .0 4 )个和 (2 5 .2 0± 5 .83)个。 3个时间组相应区域凋亡神经元数比较均存在显著性差异(P <0 .0 0 1)。透射电镜观察可见典型的凋亡细胞形态学改变。结论 凋亡参与KA致痫大鼠癫痫发作后海马神经元迟发性死亡过程。

Objective To study the spatio-temporal profile of neuronal apoptosis in rat hippocampus after epileptic attack.Methods With a rat model of kainic acid-evoked seizures, apoptosis of hippocampal neurons was determined with the use of terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling(TUNEL) and transmission electron microscopy at 6h, 1d, 3d, 7d following seizures.Results No apoptotic neurons in hippocampus were detected in control group and 6h group. One day following seizures, apoptotic neurons were detected in CA1, CA3 and CA4 subfields. The number of apoptotic neurons increased significantly at 3d and reached the most at 7d following seizures. The 1mm linear length counts of apoptotic neurons in CA1 pyramidal layer at 1, 3, 7d following seizures were 6.60±3.69, 13.57±5.17 and 25.96±4.87 respectively. Those in CA3 were 6.48± 2.45, 13.89±2.52 and 28.80±5.39 respectively and in CA4 were 4.60±1.45, 12.20±2.04, 25.20±5.83 respectively. There were significant differences in the number of apoptotic neurons in corresponding areas of CA1, CA3 and CA4 at 1, 3, 7d following seizures(P<0.001). Typical morphological characteristics of apoptotic cell death were observed under transmission electron microscopy.Conclusions Apoptosis participates in the process of delayed neuronal death in KA-evoked seizures in rats.