Effect of 2,5-hexanedione on lymphoid organs of rats: a preliminary report.

Preliminary studies related to immunotoxicologic effects of 2,5-hexanedione, the final major metabolite of n-hexane/MnBk, were carried out in rats following single or repeated exposures. Female albino rats were given either single or seven consecutive oral doses of 0.1, 0.2, or 0.5 X LD50 of 2,5-hexanedione, and a time-related kinetic study was performed using hematology, histology, cellularity, and organ weight/body weight as major parameters. Following single exposure of 2,5-hexanedione to rats, a dose-dependent thymic atrophy was evident at the end of 7 days. The atrophy was reversible when the animals were given 7 days nonexposure rest. In contrast, there was no thymic atrophy when the animals were exposed for 7 consecutive days. Significant decline in the cellular populations of various lymphoid organs was also observed in rats exposed either to single or repeated doses of 2,5-hexanedione. Results obtained in the present study indicate that 2,5-hexanedione, a known potent neurotoxic substance, adversely affects the lymphoid organs of the immune system in rats.