Effects of Ginkgo Biloba Extract Administration on the Thyroid Gland of the Adult Male Albino Rat: A Histological, Histochemical and Morphometric Study

Introduction: Ginkgo biloba extract (EGb) has been used for many years as a dietary supplement and as a herbal treatment for a wide range of diseases. However, it was found to be associated with adverse effects. Studies should be conducted to provide an information on its safety in medicine. Aim of the Work: The goal of this study was to investigate the effects of two different doses of EGb on the thyroid gland of the adult male albino rat on the functional, histological, histochemical and morphometric levels. Material and Methods: Thirty adult male albino rats each weighing (200-250 g) were categorized into three equal groups. Group 1(control, n=10) were given distilled water. Group 2 (low dose, n=10) was given (100 mg EGb /kg b.w.). Group 3 (high dose, n=10) was given (200 mg EGb /kg b.w.). All the treatment was given orally by daily gavage for 4 weeks. At the designated time of the study, blood samples were taken for determination of serum (T3, T4 and TSH). After anesthesia, rats were scarified and thyroid lobes were dissected and processed for light and electron microscopic examinations. Follicular epithelial height, follicular diameter and colloid area % means of all groups were registered and compared. Results: EGb treated animals (groups 2 and 3) demonstrated a significant decreased serum levels of T3 and T4 and a significant increase of TSH levels when compared to the control group. The follicular cells height was significantly increased, while the follicular diameter and colloid area % were significantly decreased in groups (2&3) on comparing to control. The EGb-treated animals showed histological changes in the form of irregular follicular cells, follicular cell hypertrophy and hyperplasia, deeply stained follicular nuclei, dilated profiles of rER and Golgi apparatus, mitochondrial and lysosomal alterations, vacuolated cytoplasm and dilated interstitial blood capillaries. These changes were more pronounced in the group 3. While the follicular cells of the normally secretory active (control group) revealed a week basal lamina PAS reaction and a moderate colloid PAS reaction, the inactive follicles of groups 2 and 3 showed a moderate PAS reaction in the basal follicular lamina and a marked colloid PAS reaction. Our results demonstrated that EGb administration leads to a state of hypothyroidism. Conclusion: Considerations should be taken in cases where the EGb is used as a necessary treatment. Personal non-commercial use only. Anatomy copyright © 2018. All rights reserved DOI: 10.21608/EJANA.2021.171456 Received: 01 June 2017, Accepted: 16 June 2016