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.

► The method of daily sperm production has been characterized with respect to several methodological steps and the complete protocol is available as additional material.
► Prenatal exposure to nanoparticles may adversely effect male reproduction in male offspring.
► The mechanism of effect might differ between types of particles, and for carbon black the effect seems confined to the male germline.
► Sperm production and testicle size differs in offspring according to paternal and maternal genetic background of the C57BL/6JBomTac and CBA/J mouse strains.