Detrimental effects of prenatal exposure to filtered diesel exhaust on mouse spermatogenesis

We recently showed that prenatal exposure to diesel exhaust (DE) disrupts spermatogenesis in mouse offspring. This study was undertaken to determine whether filtered DE in which 99.97% of diesel exhaust particles > 0.3 mu m in diameter were removed affects spermatogenesis in growing mice. After prenatal exposure to filtered DE for 2-16 days postcoitum, we examined daily sperm production (DSP), testicular histology, serum testosterone levels and mRNA expression of hormone synthesis process-related factors. In the filtered DE exposed group, DSP was markedly reduced at 12 weeks compared with the control group; clean air exposed group. Histological examination showed multinucleated giant cells and partial vacuolation in the seminiferous tubules of the exposed group. Testosterone was elevated significantly at 5 weeks. Moreover, luteinizing hormone receptor mRNA at 5 and 12 weeks, 17 alpha-hydroxylase/C17-20-lyase and 17 beta-hydroxysteroid dehydrogenase mRNAs at 12 weeks were significantly elevated. These results suggest that filtered DE retains its toxic effects on the male reproductive system following prenatal exposure.