Effects of monochlorobimane on cerebral ischemia-induced damage to mitochondria.

A possible involvement of inhibitory effects of monochlorobimane (MCB) on the opening of mitochondrial permeability transition (MPT) pore in the cerebroprotection against the ischemic brain injury was examined. MCB (1 mM) inhibited the opening of MPT pore in vitro. Sustained cerebral ischemia was induced by injecting 900 microspheres (48 microm in diameter) into the right hemisphere of rats. At 12 to 72 h after microsphere embolism (ME), the mitochondrial activity was determined histochemically by staining cytochrome c oxidase (COX) and succinate dehydrogenase (SDH) of the brain sections. The COX and SDH stainings in the hippocampus were observed intensively in the pyramidal neurons in the CA2-3 and dentate gyrus rather than those in the CA-1 region. The staining was decreased with time after the embolism. Pretreatment with 10 microg/animal MCB 30 min prior to the embolism significantly attenuated the ME-induced reduction in the staining of COX and SDH in the hippocampus, but not in the pariatal cortex. The results suggest that prevention of the opening of MPT pore by MCB may play an important role in the cerebroprotection against cerebral ischemic injury.