In present study, it is investigated that Dimethoate, an organophosphate group of insecticide adversely affect thyroid histopathology and thyroid stimulating hormone level in serum after chronic exposure. 15 mg/L of Dimethoate was administered to a group of mice through drinking water for 8 weeks, 10 weeks and 12 weeks. After dimethoate treatments histopathological studies of thyroid showed similarities with thyroid carcinomas. Follicles due to interfollicular interactions gradually get extended forming cohesive masses of expansile nature as “Pleomorphic Giant follicle”. The results also showed hypothyroidism by transient hyperthyroidism (Thyrotoxicosis). In tenth week of dimethoate treatments, transient hyperthyroidism might have caused by disruption of thyroid follicles and secondary release of thyroid hormones. Formation of Pleomorphic Giant follicle was started with acinus single hyperplastic thyroid follicle in 8th week of treatment. It seems that as a result of dimethoate treatment there is gradual adhesion of two or more than two acinus. Cell surface adhesion molecules and matrix-binding proteins may mediate this homotypic cell fusion and results into formation of Pleomorphic Giant follicles as invasive thyroid carcinoma in thyroid gland of mice.
Mice, Thyroid, Dimethoate, Invasive, Carcinoma
