Acute energy deprivation syndromes: investigation of m-dinitrobenzene and alpha-chlorohydrin toxicity on immortalized rat brain microvessel endothelial cells.
Acute energy deprivation syndromes share a common pattern of CNS pathology resulting in symmetrical spongiform brain stem lesions in rodents. However, some toxicants are proposed to act on astrocytes alone (alpha-chlorohydrin) whilst others are associated with petechial haemorrhages and blood-brain barrier (BBB) breakdown (m-dinitrobenzene). In this study, we investigated the toxicity of alpha-chlorohydrin (alpha-CH) and m-dinitrobenzene (m-DNB) in an in vitro BBB model, the rat brain capillary endothelial cell line RBE4. Cytotoxicity was observed after treatment of RBE4 cells with both toxicants, as manifested by a decrease in protein content and MTT reduction (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) over control values at concentrations > or = 1 mM for m-DNB and > or = 20 mM for alpha-CH. m-DNB caused a dose-dependent increase in glucose consumption and lactate production in RBE4 cells, while alpha-CH had no effect on these parameters. The distribution of F-actin at the cell margin observed in control cultures was changed to a diffuse pattern over the cell cytoplasm after treatment with both toxins at subcytotoxic concentrations. However, a reduction in F-actin content was only observed at concentrations > or = 1 mM for m-DNB and > or = 20 mM for alpha-CH. The permeability of RBE4 cell monolayers cultured on filters above primary rat astrocytes was measured using 14C-sucrose (M.Wt.=342) and FITC-dextran (M.Wt.=4000). m-DNB (0.5 mM) increased the permeability of RBE4 cell monolayers to both tracers, while alpha-CH (30 mM) had no effect. The results from this study indicate that m-DNB may have direct toxic effects on brain endothelial cells which lead to loss of barrier function. Whilst alpha-CH caused some toxic effects in RBE4 cells, it did not alter endothelial cell monolayer permeability.
Romero
I A
IA
Biomedical Sciences Division, King's College London, Strand, U.K.
Rist
R J
RJ
Chan
M W
MW
Abbott
N J
NJ
D000818:Animals; D001921:Brain / Q000187:drug effects*; D002460:Cell Line; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004136:Dinitrobenzenes / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004727:Endothelium / Q000187:drug effects*; D004734:Energy Metabolism / Q000187:drug effects; D009498:Neurotoxins / Q000633:toxicity*; D051381:Rats; D013997:Time Factors; D000517:alpha-Chlorohydrin / Q000633:toxicity*
D004136:Dinitrobenzenes; D009498:Neurotoxins; D000517:alpha-Chlorohydrin; C017906:3-dinitrobenzene