Effect of Selenium and Zinc Supplementation on Hypothyroidism in Rats

Abstract

The aim of the present study was to investigate the effect of selenium and zinc supplementation on thyroid hormones (THs) in rats suffering from hypothyroidism (HT). Forty eight adult male albino rats (200 7 g) were divided in two main groups. The first main group (n=6) was a -ve control, the second main group (n=42) was injected with PTU to induce HT. Then, these rats were divided into seven subgroups, subgroup one was fed on basal diet as a positive control; subgroups 2 -3 were fed on basal diet supplemented with sodium selenate at two levels. While subgroups 4-5 were fed on basal diet supplemented with zinc carbonate at two levels. Subgroups 6 -7 were fed on basal diet supplemented with the combination of sodium selenate and zinc carbonate. At the end of the experimental period (6 weeks), rats were sacrificed to get serum. Biochemical analysis of serum THs, Se, Zn and GPx were determined. The results indicated that PTU treated rats showed significant reduction in FT4 and FT3 levels, however, TSH level was significantly increased compared to the (ve) control group. Administration of Se and /or Zn in the diet at the two levels of intake caused an improving in HT status as related to significant increase in the concentration of both FT4 and FT3 levels and significant reduction in the level of TSH. Also, the weight of thyroid gland was significantly decreased compared to the positive control group. Also, it was observed that the serum concentrations of Se, Zn and GPx were significantly increased for all treated groups. Histopathological examination revealed that PTU treated rats showed an enlarged and dilated thyroid follicles lined with flattened epithelium and congested capilleries. Administration of Se and Zn at the two combination levels of intake showed no histopathological changes when compared to the control (-ve) group. In conclusions, diet supplemented with combination of Se and Zn at the tested levels resulted in an improvement of biochemical and histological changes resulted from HT. It could be suggested that Zn and Se at the tested levels could be used as a suitable supplementation therapy for hypothyroid patients.