Diazinon-induced ulcerative keratitis in C57bl/6 mice

As a well-known organophosphate insecticide, diazinon (DZN) has been used for several decades in agriculture. The major signs of ophthalmic toxicity of DZN have been reported to be cholinergic overstimulation (lacrimation, myosis). Here, we report, for the first time, ulcerative keratitis in C57bl/6 mice secondary to sub-acute exposure to DZN. Four groups of female C57bl/6 mice were administered intraperitoneally either DZN (1, 5, 25 mg/kg/day) or vehicle for 14 consecutive days. Then, histopathological examinations on mice eyes were performed using light microscope and scored for corneal keratitis. Furthermore, blood cholinesterase activity, and hematologic examinations were performed. Data indicated a significant ulcerative keratitis with prompt vision loss in mice exposed to 25 and 5 mg/kg/day (P < 0.05) doses. These results suggest that diazinon might induce ulcerative keratitis secondary to its immunosuppresive effects at high doses in C57bl/6 mice.