Ginkgo biloba, friend or foe of thyroid follicular cells of adult male albino rats

Abstract

Background Extract from the leaves of the Ginkgo biloba tree are used as a herbal remedy and dietary supplement. Numerous studies have suggested its therapeutic activity against many health disorders. However, it was found to be associated with histological changes in some organs. Recently, increased awareness about its safety and the potential hazards associated with its use were spotlighted. Aim The goal of the study was to assess the impact of G. biloba extract (GBE) on the histological structure and function of thyroid follicular cells of adult male albino rats. Materials and methods Thirty rats were categorized into three equal groups: group I, group II, and group III. Animals of group I were given distilled water and served as controls. GBE was given (100 mg/kg) orally for 4 and 6 weeks to group II and group III rats, respectively. At the designated times of the study, blood samples were taken for determination of serum triiodothyronine, thyroxin, and thyroid stimulating hormone. Rats were then euthanized, and thyroid lobes were processed for both light and electron microscopic examinations. Results The groups of animals exposed to GBE experienced histological changes in the follicular cells. These lesions included hypertrophy and hyperplasia of follicular cells. Group II showed evidence of hypertrophy wherein the follicles were lined with tall columnar cells. Nevertheless, group III showed many follicles lined with more than one layer of cells, along with colloid depletion. Ultrastructurally, dilated rough endoplasmic reticulum and swollen disrupted mitochondria as well as nuclear changes were further encountered in both groups. These histological changes were accompanied by alteration in the measured hormonal levels. Conclusion The study concluded that GBE administration to albino rats, either for 4 or for 6 weeks, caused alteration of thyroid follicular cell structure and function.