[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 regulation 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, bcl-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 demyelination in the white matter is a prevailed pathological change of HSLE. Oligodendrocyte apoptosis under induced by the decrease of bcl-2/bax ratio may contribute to the pathogenesis.