[Roles of bcl-2/bax expression and oligodendrocyte apoptosis in the pathogenesis of heroin-induced spongiform leucoencephalopathy].

Objective To investigate the role of oligodendrocyte apoptosis under the regulafion of the bcl-2/bax protein expression in brain white matter in the pathogenesis of heroin-induced spongiform leucoencephalopathy (HSLE).Methods Samples of frontal lobe,cerebellum,and corpus callosum were obtained from the brains during autopsy of 4 HSLE cases and 5 normal controls and underwent light microscopy and electron microscopy. Immunocytochemistry was used to detect the expression of myelin basic protein(MBP),caspase-3,bel-2 protein,and bax protein.Results Widespread demyelination was seen in the white matter of the frontal lobe,cerebellum and corpus callosum of the HSLE cases,most severely in the cerebellum.The levels of caspase-3 and bax expression of the HSLE group were significantly higher than those of the control group(both P＜0.05),however,the bcl-2 level of the HSLE group was no significantly different from that of the control group(P＞0.05).Conclusion Widespread demyelinafion in the white matter is a prevailed pathological change of HSLE.Oligodendrocyte apoptosis under induced by the decrease of bel-2/bax ratio may contribute to the pathogenesis. Key words: Heroin;  Canavan disease;  Oligodendroglia;  Apoptosis;  Gene expression