Protective Effect of Zinc Sulfate on Hypo-and Hyperthyroidism Induced in Adult Male Rabbits

Abstract

The present study was conducted to investigate the effect of co-administration of zincsulfate with Carbimazole (CBZ) and, Levothyroxine (L-T4) on thyroid gland function inadult male rabbits. Fifty adult male rabbits, were divided randomly into five equal groups (6rabbits/group) as follows: The first group (control group): Rabbits were given oral doses ofdistilled water daily by gavage; second group (Hypothyroidism): Rabbits were given oraldoses of carbimazole (5 mg/kg. bw) daily by gavage; the third group; Rabbits were givenoral doses of carbimazole (5 mg/kg. bw) + zinc sulfate (20 mg/kg.bw); fourth group(Hyperthyroidism): Rabbits were given oral doses of L-T4 (100µg/kg.bw) daily by gavage;Fifth group: Rabbits were given oral doses of L-T4(100µg/kg.bw) + Zinc sulfate(20mg/kg.bw) daily by gavage. The treatment continued for 30 days. The results revealedthe following: A significant elevation in serum TSH level and a significant reduction inserum T4, T3 and, FT3 levels in CBZ treated rabbits group compared with the control group,while a significant reduction in serum TSH level and a significant elevation in serum levelsof T4, FT4 and FT3 in animals group treated with the L-T4 compared with the control groupHistopathological changes of hypothyroidism were observed in CBZ treated groupcharacterized by small thyroid follicles, increase the height of thyrocytes hyperplasia, andvacuolation of colloid. L-T4 and L-T4-Zinc treated groups showed large follicles distendedwith homogenous acidophilic colloid. No significant changes in thyroid architecture wereobserved in CBZ-Zinc treated group compared with the control group.