摘要：
目的 对比观察大鼠海人酸点燃海马与杏仁核癫痫模型不同发作期的行为学、皮质脑电及海马病理学变化.方法 雄性成年Sprague-Dawley大鼠24只,按随机数字表法分为海马组、杏仁核组(模型组各9只,对照组各3只).将海人酸0.6μl(0.6μg,1.0μg/μl)定向注射到大鼠海马CA3区或杏仁核区建立两种癫痫模型.模型建立成功的大鼠按随机数字表法分为癫痫发作后1 d(急性期)、7 d(潜伏期)、30 d(慢性期)组,每组各3只.对照组于海马CA3区或杏仁核区注入等体积的生理盐水.观察不同发作时期大鼠的行为学和皮质脑电变化.采用免疫组织化学染色方法观察海马中神经元的标志物神经元核蛋白(NeuN)、星形胶质细胞的标志物胶质纤维酸性蛋白(GFAP)及小胶质细胞的标志物离子钙结合衔接分子1(IIba1)表达的变化.结果 两种癫痫模型急性期及慢性期均有典型癫痫发作的行为学及脑电表现.海马模型组注入海人酸后(63.33±4.41)min出现部分性发作,间断伴有癫痫大发作;皮质脑电表现以多相棘波多见.杏仁核模型组注入海人酸后(28.67±3.48)min主要出现癫痫大发作;皮质脑电以尖波发作性节律多见.免疫组织化学染色显示,与对照组比较,从急性期到慢性期,两种模型在海马CA1、CA3和CA4区均为神经元丢失和星形胶质细胞增生逐渐加重,同时伴小胶质细胞在神经元丢失部位逐渐增多、聚集.但与海马模型组比较,杏仁核模型组慢性期在CA1和CA4区神经元丢失[CA1区NeuN的吸光度(A)值为10.83±1.52对比22.43±5.16,P<0.01;CA4区为12.87±2.13对比25.81±4.60,P<0.05]及星形胶质细胞增生(CA1区GFAP A值为61.20±7.33对比14.65±0.12,CA4区为76.73±5.40对比43.01±1.35,均P<0.01)更明显,CA1区小胶质细胞广泛聚集现象更严重(IIba1 A值为13.70±3.88对比1.08±0.01,P<0.01).结论 大鼠海人酸点燃海马及杏仁核癫痫模型均能模拟人颞叶癫痫特征,但在行为学、皮质脑电表现,特别是海马病理学改变方面存在差异.%Objective To compare the behavioral manifestations, electroencephalogram ( EEG ) monitoring and hippocampal pathological changes in two rat epilepsy models induced by kainic acid ( KA) injected into hippocampus and amygdala respectively. Methods Male adult Sprague-Dawley rats(n=24) were randomly divided into hippocampus model group ( n=9 ) , amygdala model group ( n=9 ) and control group (n=6). Two epilepsy models were established by kainic acid (0. 6 μg,1. 0 μg/μl) stereotactically injected into hippocampus CA3 region (hippocampus model) or amygdala (amygdala model). The status epilepticus ( SE ) of rats was observed by behavioral manifestations and EEG monitoring. Following successful modeling, those rats were randomly divided into 3 groups, including 1-day ( acute phase) , 7-day ( latent phase) and 30-day ( chronic phase) post SE groups ( n=3 in each group) . Rats in the control group were injected with an equal volume of saline in the hippocampal CA3 or amygdala. Immunohistochemistry was used for observing the pathological changes of neuron (NeuN), astrocyte (GFAP) and microglia (Iba1) in the rat hippocampus. Results Behavioral and EEG monitoring showed that rats from both models had typical seizure behaviors and EEG characteristics in the acute and chronic phases. However, there were different seize types and onset time between the 2 models in the acute phase. The hippocampus model group had partial seizures at 63. 33 ± 4. 41 min post KA injection with intermittent generalized tonic-clonic seizures. Multi-phase spikes were recorded in acute phase. Amygdala model group had severe generalized tonic-clonic seizures at 28. 67 ± 3. 48 min post KA injection, and the main cortical EEG form was sharp wave rhythm. Immunohistochemical staining revealed gradual hippocampal neuron death from acute to chronic phases in both models, which resulted in serious neuronal loss. Meanwhile, the aggravation of astrocyte proliferation and accumulation of microglia occurred in hippocampus in both models. Remarkably, compared with hippocampus model, the amygdala model in chronic phase had more neuronal loss in CA1 region ( 10. 83 ± 1. 52 vs. 22. 43 ± 5. 16, P<0. 01) and CA4 region (12. 87 ± 2. 13 vs. 25. 81 ± 4. 60, P <0. 05), more astrocyte proliferation in CA1 region (61. 20 ± 7. 33 vs. 14. 65 ± 0. 12, P<0. 01) and CA4 region (76. 73 ± 5. 40 vs. 43. 01 ± 1. 35, P<0. 01) as well as more widespread accumulation of microglia in CA1 region (13. 70 ± 3. 88 vs. 1. 08 ± 0. 01, P<0. 01). Conclusions Our results have indicated that both rat epilepsy models simulated human temporal lobe epilepsy. The differences in the behavior, EEG performances and particularly pathological changes of hippocampus between two models should be taken into consideration in the future study.
