Reproductive toxicology of aluminum in male mice.
The reproductive toxicology of aluminum was studied in mice. Adult male mice were treated intraperitoneally with aluminum nitrate at doses of 0, 50, 100, and 200 mg/kg/day for 4 weeks before mating with untreated females. Decreased body weight was seen in all aluminum-treated groups. Decreased pregnancy rate was observed in the females mated with males previously treated with 100 or 200 mg/kg/day of aluminum nitrate. High-dose male mice showed significantly decreased testicular and epididymal weights, as well as significant decreases in testicular and spermatid counts and epididymal sperm counts. Spermatid counts were also reduced at 100 mg/kg/day. However, the sperm motility was unaffected, and the percentages of morphological normal spermatozoa in all mice exposed to aluminum were comparable to the values in control mice. Histological changes, including necrosis of spermatocytes/spermatids, were observed in the testes of male mice treated with 100 and 200 mg/kg/day of aluminum nitrate, whereas the tubular diameters were unaffected by aluminum administration. The current study demonstrates adverse effects of parenteral aluminum exposure on the mouse male reproductive system. The "no observable adverse effect level" (NOAEL) was 50 mg/kg/day.