Effects of a low dose of bentazon on spermatogenesis of mice exposed during foetal, postnatal and adult life.

Bentazon is a herbicide used to control many broadleaf weeds and sedges. Its use has improved rice production in paddy fields in Northern Italy, but as a negative consequence it is found in groundwater, the major source of drinking water. To determine whether low doses of bentazon affect spermatogenesis, it was dissolved in water at the concentration of 30 microg/L. Bentazon was administered through drinking water to: (1) adult mice for 100 days and (2) mice exposed in utero, during lactation and for 100 days after birth. The histopathological analysis of testes of treated animals showed that the frequency of defective tubules was comparable to that found in control groups. The cell associations of the 12 stages of the seminiferous epithelium were correct as well as the architecture of the epithelium. The spermatocytes/spermatids ratio was the same as in controls. However, the frequency of stages VII, IX and XII of the cycle of the seminiferous epithelium of adult mice and of stages I, III and VII of mice exposed in utero and for 100 days after birth was different when compared to that of control mice. Sperm number and morphology were not affected by the treatment. The potential genotoxic effects were evaluated on spermatozoa (Comet assay), in pachytene spermatocytes (analysis of the synaptonemal complex) and in bone marrow cells (frequency of micronuclei). None of these analyses evidenced genotoxic effects of bentazon. Although our results show that the administration of a low dose of bentazon does not impair spermatogenesis, we found alterations of the frequency of some stages of the cycle of the seminiferous epithelium in both experimental groups.