Carcinogenic and cytotoxic effects of Diazinon in the mouse: an in vivo and in vitro study

In this study, the toxicity and carcinogenicity of an organophosphate pesticide, diazinon, were studied in the mouse by MTT, micronucleus and karyotype methods. Morphological changes of cell lines in the vicinity of diazinon were also evaluated and recorded.

Mice were randomly divided into two groups (n=15 per group): treatment and control groups. In the treatment group, diazinon (1 ml of 1 ppm concentration) was applied once daily topically on the shaved skin and for 12 weeks; in the controls, physiological salt solution was used. At the end of the period, tissue samples were taken from the organs after autopsy. Murine L929 fibroblast cells were cultured with and without diazinon (10, 25, 50, 100 µg/ml). The morphological changes of the cells were evaluated after 48 hours. The cytotoxicity was assessed in vitro by MTT assay and micronucleus and karyotype and IC50 percent were also determined.

Microscopic observations of kidney tissue revealed mild cytotoxicity in proximal tubules. Mild hepatotoxicity was also observed in the liver tissue. Morphological results of cell line showed that diazinon (50 μg/ml) had a significant effect compared to the control group. The percentage of micronucleus in the group treated with 100 µg/ml of diazinon was significantly higher than the control. In the MTT assay, the mean optical absorption at concentrations of 10, 25, 50, 100 μg/ml was significantly different from that of the control group (P <0.05).

Skin contact with Diazinon induces pathologic effects on organs, cytotoxicity, and procarcinogenic effect in mice.