目的探讨年龄、惊厥持续时间对持续惊厥(status convulsion,SC)后海马神经元凋亡的影响。方法制作幼年和成年Wistar鼠SC模型,于SC持续30min及3h后不同时间点处死,TUNEL染色观察凋亡细胞的类型和分布;Annexin-V染色,流式细胞仪定量分析凋亡过程。结果(1)SC持续50min后5h,幼年和成年鼠海马凋亡细胞[分别为(0.55%±0.21%)和(0.55%±0.06%)]较惊厥前均有显著增加。凋亡过程持续3~7d。(2)除SC持续30min后3h以外,在其他各观察时点上,幼年组海马凋亡细胞数量均低于成年组。(3)sc持续3h后,海马凋亡细胞均高于SC持续30min实验组,以成年组更为明显。结论惊厥后海马神经元凋亡与年龄和惊厥持续时间呈明显正相关。
Objective To explore the influences of age and duration of status convulsion (SC) on hippocampal neuron apoptosis by observing the dynamic change of neuron apoptosis in rats with different age when SC terminates. Methods Seizures were induced in infant rats (IRs) and adult rats (ARs) injected with lithium and pilocarpine intraperitoneally. Rats were sacrificed at 6 time points (3, 6, 12 hours and 1, 3,7 days) after 30 minutes of SC, or 2 time points (3 hours and 1 day ) after 3 hours of SC respectively. The location and type of apoptotic cells were assessed by using terminal deoxynucleotidyl dUTP nick endlabeling (TUNEL) of brain sections in situ. The proportion of apoptotic cells was quantified by Annexin-V- FITC apoptosis detecting method and analysed by flow cytometer. Results ( 1 ) SC induced neuronal apoptosis and necrosis mainly in the CAI and CA3 regions of hippocampus. (2) As compared to the time point before SC, the proportion of apoptotic cells in IRs and ARs hippocampus was increased obviously at 3 hours point after 30 minutes of SC ( IRs 0. 55% ± 0.21% , ARs 0. 53% ± 0.06% ) , and with a maximal induction at 12 hours in IRs (0.67%±0. 18%) and 1 day in ARs (0.98% ±0.38%). The apoptotic process continued at least for 3--7 days. (3) In IRs, the proportion of apoptotic cells was lower than in ARs at different time points after 30 minutes of SC, except 3 hours point. There was a significant difference between the two age groups at 1 day and 7 days after SC respectively. The age-related difference was more obvious after 3 hours SC. Conclusions ( 1 ) Severe seizure induces neuronal apoptosis in hippocampus. (2) Age and duration of SC might be the important factors in influencing the neuronal apoptosis. The neuronal apoptosis in hippocampus after SC would have a positive correlation with age and duration of SC.