Vascular wall damage in rats induced by organophosphorus insecticide methidathion.

We have examined the effect of subchronic methidathion (MD) administration on vascular wall damage. The experimental groups were: control group and rats treated with 5 mg/kg MD. The MD group was given MD by gavage for 5 days a week for 4 weeks at a dose level of 5 mg/kg per day by using corn oil as the vehicle. The levels of malondialdehyde (MDA) were determined in the vascular tissue. Histopathological examination was examined in the thoracic aortic tissue. The levels of MDA were increased in the MD group compared with the control group (P < 0.01). In the MD group, subchronic MD administration led to the irregulation, prominent breaks and fragmentation of the elastic fibers were located in the media of aortic wall. In conclusion, it is likely that subchronic MD administration caused vascular wall damage and, in addition, lipid peroxidation may be one of the molecular mechanisms involved in MD-induced vascular toxicity.