环己酮二腙诱导大鼠脑白质脱髓鞘及细胞凋亡的实验研究

目的:探讨双环己酮草酰二腙(cuprizone)诱导大鼠脑白质脱髓鞘及其病因,证实双环己酮草酰二腙引起脑白质脱髓鞘与细胞凋亡有关。方法:用环己酮草酰二腙制备大鼠脑白质脱髓鞘模型(酮腙组),与安定(安定组)、苯巴比妥(苯巴比妥组)、生理盐水对照组(对照组)比较,应用电镜技术及caspase3免疫组化染色,观察各组第14天、28天、42天时脑组织结构变化及细胞凋亡的信号传导通路。结果:电镜显示,安定组、苯巴比妥组、酮腙14天组和对照组白质结构完整致密,无脱髓鞘现象;酮腙28天组可见髓鞘排列较紊乱,部分结构松解变性,但无典型脱髓鞘改变;酮腙42天组胼胝体压部可见髓鞘肿胀,多部位髓鞘被涡轮状空泡所裂解。caspase3染色:酮腙28天、42天组可见皮层下白质、胼胝体、脑干及小脑白质caspase3阳性染色,与安定组、苯巴比妥组、对照组和酮腙14天组比较差异具有统计学意义(P<0.05);酮腙42天组caspase3阳性染色明显多于28天组,差异具有统计学意义(P<0.05)。结论:环己酮草酰二腙可诱导大鼠脑白质脱髓鞘、空泡样变;病变白质区存在大量caspase3阳性染色,且早于脱髓鞘。提示:caspase蛋白酶级联反应参与了环己酮草酰二腙诱导脑白质脱髓鞘的过程,进一步说明细胞凋亡可能是脑白质脱髓鞘原因之一。

The Cuprizone Induced the Brain White Matter Demyelination and Apoptosis in the Rat Brain*

Objective: To explore the bicyclic cyclohexanone oxalyl hydrazone(cuprizone) induced white matter demyelination and its causes,confirmed the demyelination was caused by white matter apoptosis.Methods: Cuprizone was used to make the rat brain white matter demyelination and vacuolation model(Cu),compared with Diazepam,Phenobarbital and physiological saline group.Structural changes and apoptosis signaling pathways in brain tissue during the application of electron microscopy techniques and caspase3 immunohistochemical staining observed in each group 14days,28days and 42days after treatments.Results: White matter structure was integrity and dense,non-demyelinating in the normal alba;Arranged irregular myelin were observed in the Cu 28d,part of the structure release variability,but no typical demyelination,We observed myelin swelling,vacuolation,myelin sheath cracking by turbo-like vacuoles at corpus callosum in the Cu 42d group.Caspase3 positive staining: Cu 28d and Cu 42d group had Statistically significant difference compare with diazepam,Phenobarbital and Cu 14d groups at subcortical white matter,corpus callosum,brain stem(P<0.05).Cu 42d was significantly more than Cu 28d(P<0.05).Conclusion:The cuprizone induced white matter demyelination,vacuolar degeneration;There are a large number of caspase3 positive staining in the lesions of white matter,and earlier than the demyelination.Suggesting that the caspase protease cascade of reactions involved in the cuprizone induced white matter demyelination,further demonstrate apoptosis may be one of the reasons of matter demyelination.