Evidence for zinc protection against 2,5-hexanedione toxicity by co-exposure of rats to zinc chloride

The protective role of zinc against the toxic effects of 2,5‐hexanedione (2,5‐HD), the main neurotoxic metabolite of n‐hexane, was investigated by studying the interference of zinc on the toxicokinetics of 2,5‐HD. Six groups of Wistar rats were exposed for 3 days to diets containing 2,5‐HD, zinc chloride and 2,5‐HD+zinc chloride. The amounts of pyrroles and free and total 2,5‐HD in urine were determined using Ehrlichs's reagent and gas chromatography/flame ionization detection, respectively. The results show that after the first day of co‐exposure (ZnCl2+2,5‐HD) there was a significant decrease in the excretion of pyrroles and free 2,5‐HD in rats exposed to the chemical mixture when compared to the pyrroles and free 2,5‐HD excreted in rats exposed to 2,5‐HD alone. However, no significant decrease was observed in the urinary excretion of total 2,5‐HD (free 2,5‐HD + preformed 2,5‐HD). Suggestions are made about the role played by this metal ion in inhibiting pyrrole formation. Copyright © 2000 John Wiley & Sons, Ltd.