Kidney metabolism and sex related nephrotoxicity of 1,2-dichloropropane in vitro

1,2-Dichloropropane (1,2 D) causes kidney alterations during subchronic treatment of rats. The aim of the present work was to study kidney metabolism and sex related nephrotoxicity of the solvent using renal cortical slices as an in vitro model. The slices were obtained from young adult male and female Wistar rats, prepared according to Smith et al. and incubated with 1,2 D, 1-chloro-2-hydroxypropane (CH) or 1,2-epoxypropane (EP) at doses ranging between 5 and 25 x 10-3 M. After incubation for 90 minutes at 37°C, the slices were prepared for the measurement of reduced glutathione content (GSH) or reincubated (90 minutes at 25°C) with p-aminohippurate (PAH) to study the organic anion accumulation. The medium of the first incubation was tested for malondialdehyde (MDA) content as an index of lipid peroxidation. Other slices were gassed before treatment with carbon monoxide (CO) for 5 minutes or preincubated (30 minutes at 37°C) with aminooxyacetic acid (AOAA) 10-3 M. EP caused a complete depletion of male and female rat GSH content even at the lowest dose tested. The depletion was also significant after treatment with 1,2 D (up to 59 and 69%, respectively) and CH (up to 47 and 50%, respectively) and was significantly higher for males than females. A similar behaviour was observed for PAH accumulation. 1,2 D and CH caused a slight, not significant increase of MDA in the medium whereas EP induced a high increase up to ten-fold, the extent of lipid peroxidation being higher in females than in males. Slices gassed with CO showed no GSH depletion after treatment with 1,2 D showing that the toxic effects were likely to be due to metabolism of the solvent to toxic metabolites. The inhibition of microsomal metabolism indeed prevented the toxicity. AOAA preincubation, an inhibitor of ß-lyase, a pyridoxal phosphate-dependent enzyme, prevented GSH depletion and loss of PAH accumulation after 1,2 D treatment partially, but significantly. The results obtained with the in vitro model show that: (a) the toxic effect of 1,2 D are greater in male than in female rats; (b) kidney may metabolize in situ 1,2 D to nephrotoxic metabolites; (c) toxicity is due to EP and possibly to a thiol formed via ß-lyase activation; (d) the most relevant effects are GSH depletion and loss of anionic transport (decrease of PAH accumulation).