甲基氧化偶氮甲醇诱导皮质发育障碍动物模型的研究

Animal models of cortical development malformation induced by methylazoxymethanol acetate

目的建立经甲基氧化偶氮甲醇（MAM）诱导的新型皮质发育障碍（MCD）大鼠模型，研究其病变程度与鼠龄的关系、癫痫易感性及发作对病理形态的影响。方法妊娠的SD大鼠按照随机数字表法分为MAM组与对照组，MAM组在妊娠的第15灭给予二次腹腔注射MAM（15mg／kg）建立MCD模型，对照组注射生理盐水；观察子鼠行为并检测脑电图。琉瑾-吉姆萨染色、NeuN免疫荧光染色动态观察病理形态。采用匹鲁卡品诱发实验研究癫痫易感性及发作对病理形态的影响。结果与对照组相比，MAM组子鼠反应迟钝，活动量减少，癫痫易感性增高。病理及免疫荧光染色示MAM组子鼠皮质变簿、层状结构紊乱，皮质和海马内存在团块状增殖结节、异位神经元和胞体较大的异形神经元；上述病理改变因鼠龄不同而存在差异，呈现鼠龄越长病理改变越明显的趋势。与单纯MAM组比较，经历匹鲁卡品诱导癫痫发作后的MAM组子鼠皮质发育异常加重。结论二次腹腔注射MAM可建立MCD模型，其病理特征与MCD患者极为相似．且病变程度与鼠龄有关；联合匹鲁卡品诱导癫痫发作后其病变程度加重，是建立MCD癫痫模型的较佳方法。

Objective To establish the new animal models of malformation of cortical development （MCD） induced by methylazoxymethanol acetate （MAM）, and analyze the relationship between extent of histopathology and age, seizure susceptibility and effect of seizure on the histopathology. Methods Pregnant Sprague-Dawley rats were randomly divided into MAM group and control group; rats in the MAM group received twice intraperitoneal injection of MAM （15 mg/kg） to establish MCD models on embryonic day 15, while rats in the control group only given normal saline. Daily activities and EEG features of the next generation rats were observed; Thioine-Giemsa staining and immunofluorescence staining of NeuN were applied to observe the histological changes. Pilocarpine was administrated to investigate the effects of seizure susceptibility and epilepsy seizure on pathological morphology. Results The MAM rats were dull and curtail their activities, their seizure susceptibility elevated. The histopathological and immunofluorescence staining results revealed that the MAM rats＇ cerebral cortex decreased and the laminar organization was disrupted; there were heterotopic neuros, hypertrophic neurons and proliferation nodules in the hippocampal and cortex; the pathology changes exacerbated with age. The malformation of cortical development was more serious in the MAM rats which experienced seizure than the MAM rats. Conclusion The MCD rat models can be established by twice intraperitoneal injection of MAM, and their pathological features resemble the patient of MCD and their pathology exacerbate with age. Seizure can aggravate the pathology of MCD. Combiningutilization MAM and pilocarine could be a good approach to establish animal models of epilepsy based on MCD.