AN IN-VITRO STUDY OF M-DINITROBENZENE TOXICITY ON THE CELLULAR-COMPONENTS OF THE BLOOD-BRAIN-BARRIER, ASTROCYTES AND ENDOTHELIAL-CELLS

We have studied the effects of an industrial compound, m-dinitrobenzen e (DNB), on cultured astrocytes and brain capillary endothelial cells in an in vitro blood-brain barrier (BBB) model. In single cultures, th e threshold DNB concentration that induced cell death, as assessed by morphology and lactose dehydrogenase leakage into the culture medium, was 1 mM for both cell types after 1 day of incubation, In cocultures, astrocytes showed a dose-response curve similar to that obtained in s ingle cultures, while endothelial cells showed an increased sensitivit y to DNB cytotoxicity, DNB induced a dose-dependent increase in glucos e consumption and lactate production in both cell types in single cult ures, although astrocytes appeared to be more sensitive than endotheli al cells. The role of oxidative stress was also studied using the redu ction of nitroblue tetrazolium as an index of generation of active oxy gen species. A dose-dependent increase was observed for both cell type s in single cultures, although this could not be prevented by the addi tion of superoxide dismutase to the culture medium, Addition of 0.3 mM carmustine to the culture medium increased the cytotoxicity of 0.5 mM DNB in both astrocytes and endothelial cells, indicating a role of ox idative stress in DNB-induced damage, Desferrioxamine (20 mM) complete ly protected endothelial cells from damage by 1 mM DNB, suggesting tha t hydroxyl radicals mediated at least part of the DNB neurotoxicity. H owever, astrocytic damage by 2 mM DNB was only partially prevented by desferrioxamine. We conclude that our in vitro model is suitable for s tudying interactions between astrocytes and endothelial cells in toxic ological situations. (C) 1996 Academic Press, Inc.