Quantitative cytophotometric analysis of brain neuronal RNA and protein changes in acute T-2 mycotoxin poisoned rats.

ABSTRACT

Male Sprague-Dawley rats (200 g) injected intraperitoneally with T-2 toxin, a trichothecene mycotoxin protein synthesis inhibitor, at dosages of 0.75, 1.0, 1.5 and 6.0 mg/kg (1 LD50 = 0.9 mg/kg) were decapitated at 8 hr post-exposure. Data were obtained on changes in neuronal (perikaryal) RNA levels, protein contents and nucleolar volumes in cerebrocortical (layer III) and striatal (caudate-putamen) brain regions using quantitative azure B-RNA and Coomassie-protein cytophotometry and ocular filar micrometry. Correlative observations were made on changes in brain cytomorphology. Reductions in neuronal RNA/protein contents and nucleolar volume were used as indices of impaired perikaryal functioning. At 8 hr after T-2 toxin poisoning the following results were obtained in cerebrocortical and striatal brain compartments neuronal RNA contents were generally maintained at control values in both brain regions, however, moderate RNA depletion was evidenced in the cerebral cortex with 1.5 mg/kg T-2 and in the striatum with a 6.0 mg/kg dose; neuronal protein levels were suppressed in a dose-dependent fashion within the cerebrocortex, while in the striatum there was no direct correspondence between protein loss and T-2 dosage; neuronal nucleolar volumes were typically maintained at control levels in both neuronal compartments. Microscopic observations revealed no gross evidence of T-2-induced brain cytopathology. These data indicate that T-2 toxin does not elicit direct cytopathic actions in these two brain regions, thus indicating that cerebrocortical and striatal compartments do not represent primary target sites of T-2 toxicant action.(ABSTRACT TRUNCATED AT 250 WORDS)