Effect of malathion on the male reproductive organs of earthworms, Eisenia foetida.

AIM To observe the cytotoxic effect of the organophosphate insecticide malathion in the reproductive tissues of the earthworms, Eisenia foetida. METHODS Worms were nourished in soil treated with malathion at single sub-lethal doses of 0, 80, 150, 300 and 600 mg/kg soil. (LD50=880 mg/kg soil) and evaluated on days 1, 5, 15 and 30 after exposure. The body weights were recorded and male reproductive organs evaluated. RESULTS Malathion-treated animals showed a significant reduction in body weight in a dose-dependent manner. Malathion treatment modified the disposition of spermatozoa in the basal epithelium of the spermatheca. The Br-deoxyuridine test showed a significant rise in cells in phase S on days 5 and 15. Also, a higher percentage of spermatogonia with fragmented DNA were observed by means of the TdT-mediated dUTP nick-end labeling (TUNEL) technique in the spermatheca of treated animals. CONCLUSION Treatment with malathion decreased the body weight and the spermatic viability in spermatheca, altering the cell proliferation and modifying the DNA structure of spermatogonia.