Histological study on the possible protective effect of curcumin on potassium dichromate induced hypothyroidism in adult male albino rats

Abstract

Introduction: Potassium dichromate, a widely used heavy metal in several industries induces hypofunction and tissue insult of the thyroid gland via oxidative stress. Curcumin; is a natural commonly used spice has a strong anti-inflammatory and antioxidant properties. Aim of the work: To investigate the possible protective effect of curcumin on the hypothyroidism induced by potassium dichromate in albino rats. Materials and Methods: Thirty- five adult male albino rats were divided into five groups, 15 rats in group I (control) and 5 rats in each of group II, III, IV and V. Group II (curcumin group) received curcumin orally (100 mg /kg/bw) daily for 4 weeks. Group III (potassium dichromate induced hypothyroidism) received i.p injection of potassium dichromate (2 mg/kg/ bw) daily for 2 weeks. Group IV (recovery group) received potassium dichromate as group III then left untreated for another 2 weeks. Group V(curcumin and potassium dichromate group) received curcumin concomitant with potassium dichromate as in groups II and III, respectively daily for 2 weeks and only curcumin was continued for another 2 weeks. T3, T4 and TSH were assessed. Thyroid sections were subjected to toluidine blue, H&E, PAS and PCNA immunohistochemical stains. Morphometric and statistical studies were done. Results: Thyroid tissue insult and hypofunction with significantly decreased T3, T4 and increased TSH were detected in group III. Additionally, there was a significant increase in the mean values of follicular cell height, follicular diameter, mean number of PCNA positive nuclei and a significant decrease in the mean value of area percent of colloid versus group I, II and V with non-significant differences versus group IV. In group V, there was an obvious serological and histological improvement compared to group III and IV. Conclusion: Curcumin had protective effect against hypothyroidism and thyroid tissue damage induced by potassium dichromate.