Daily sperm production: application in studies of prenatal exposure to nanoparticles in mice

We investigated the influence of maternal airway exposure to nanoparticulate titanium dioxide (TiO₂, UV-Titan) and carbon black (CB, Printex90), on male reproductive function in the two following generations. Time-mated C57BL/6J mice were exposed by inhalation to UV-Titan, or by intratracheal instillation with Printex90. Body and testicle weight, sperm content per g testicular parenchyma and daily sperm production (DSP) were assessed. The protocol for assessment of DSP was optimized for application in mice (C57BL/6J) and the influence of different parameters was studied. Maternal particulate exposure did not affect DSP statistically significantly in the F1 generation, although TiO₂ tended to reduce sperm counts. Overall, time-to-first F2 litter increased with decreasing sperm production. There was no effect on sperm production in the F2 generation originating after TiO₂ exposure. F2 offspring, whose fathers were prenatally exposed to Printex90, showed lowered sperm production. Furthermore, we report statistically significant differences in sperm production between mouse strains.