Impact of Spirulina on Propylthiouracil - Induced Hypothyroidism in Albino Rats, A Histological, Immunohistochemical and Biochemical Approach

Background: Hypothyroidism is a decrease in the production of the thyroid hormones and leads to gland dysfunction. Spirulina used as an antioxidant and supposed as antihypothyroidic agent.
Objective: This study was carried out to investigate the impact of Spirulina on PTU-induced hypothyroidism in rats.
Materials and Methods: The rats were divided into six groups, control group (G1), hypothyroid group (G2), SP-500 treated group (G3), SP-1000 treated group (G4), PTU+SP-500 treated group (G5) and PTU+SP-1000 treated group (G6). Thyroid gland was examined using biochemical, histological, and immunohistochemical studies. Duration of treatments were for 14 days.
Results: A significant decline in the body weight gain was exhibited. Biochemically, a significant decrease in T3 and T4 hormone levels in the PTU-group and a substantial increase in groups treated with Spirulina alone. While PTU+ Spirulina treated groups revealed normal hormonal levels more or less similar to the control group. Histological changes such as congestion of the blood capillaries, follicular dilatation, and vacuolar degeneration of some follicular cells were exhibited in hypothyroid group G2 and Spirulina treated-groups (G3andG4). Hyperplastic cells with hyperchromatic nuclei, depleted vacuolated-thyroglobulin, and a significant increase in the epithelial heights and the follicular diameters, were observed. Immunohistochemically, low expression of the proliferative cellular marker KI-67 was expressed in the PTU and PTU+Spirulina treated groups. While negative expression of KI-67 in Spirulina treated groups was recorded.
Conclusion: Administration of Spirulina alone displayed signs of hyperactivity on the thyroid gland, but it has a mild protective role in the PTU-induced hypothyroidism groups. Therefore, caution should be used in extrapolating these results to the human being situation within different doses and durations.