The Propolis Effect on Chlorpyrifos Induced Thyroid Toxicity in Male Albino Rats

Abstract

Chlorpyrifos (CPF) is a chlorinated organophosphate insecticide that is used widely in the world and Egypt. The aim of present work was to study the possible protective role of Propolis on thyroid gland of male rats after chronic exposure of chlorpyrifos. For this purpose, Fifty adult male albino rats were randomized into 5 groups: I, II (Control), III (received Propolis dissolved in 0.5 ml corn oil, 50 mg/kg b.w./day), IV (received CPF dissolved in 0.5 ml corn oil 6.75 mg/kg b.w./ day) and V (received CPF and Propolis at the same previously mentioned doses). Rats were orally treated by gavage for 12 weeks. We found that Chlorpyrifos induced damaging effects in thyroid tissue architecture, thickened collagen fibers between the follicles and decreased periodic acid schiff (PAS) reaction in the colloids. Immunohistochemically, there was weak thyroglobulin (TGB) expression. Besides, it significantly decreased the serum levels of Tri-iodothyronin (T3), Tetraiodothyronin (T4) and Thyroid stimulating hormone (TSH). It depressed reduced glutathione (GSH) content and antioxidant enzyme activities in thyroid tissues with respect to control groups. Furthermore, CPF increased thyroid oxidative stress as manifested by elevated malondialdehyde (MDA) levels. On the other hand, the concurrent administration of Propolis with CPF showed significant improvement in previous changes. Our findings showed that the concurrent oral administration of Propolis with CPF improved the CPF induced oxidative damaging effects in thyroid gland and the antioxidative defense in the rats.