The Effect of Chrysin Nanocrystal on the Thyroid Gland of Rats Exposed to Chlorpyrifos.

Background: Chlorpyrifos (CPF) is an organophosphate insecticide that is mostly used in agriculture for pest control.

Aim: This investigation aimed to evaluate the possible protective role of chrysin nanocrystals on thyroid gland hormones and histology in male rats after exposure to a high dose of chlorpyrifos.

Method: Rats were randomly divided into 6 groups (6 rats in each group): 1. healthy control group, 2. treated with chrysin nanocrystal (5 mg/kg), 3. treated with chrysin nanocrystal (10 mg/kg), 4. treated with chrysin nanocrystal (5 mg/kg) + chlorpyrifos, 5. treated with chrysin nanocrystal (10 mg/kg) + chlorpyrifos, and 6. treated with chlorpyrifos (30 mg/kg). After 15 days of intervention, rats were anesthetized, and blood samples were taken from the heart to measure thyroid hormones. Then, the thyroid gland was isolated and stored in 10% formalin for histopathological studies. Thyroid samples were also stored at -80 ° C for measuring oxidative stress parameters.

Result: A significant reduction was observed in the serum concentrations of T3 and T4 in all treated groups compared with the control group (p < 0.01). In addition, hormone level examination revealed no statistically significant (p ˃ 0.05) changes in plasma TSH concentration in any of the groups. The treatment with CPF and chrysin nanocrystal did not affect the levels of oxidative biomarkers (MDA, GSH, and NO) in thyroid glands. Photomicrographs of a histological section of the thyroid gland showed vacuolar degenerated follicle epithelium and missing colloids in the histological section of the thyroid gland of all groups.

Conclusion: Our findings demonstrated that the oral administration of chrysin nanocrystals could not inhibit the toxic effect of a high dose of CPF on the thyroid gland in the rats.