Apoptotic Marker Alternations in the Spleen of Experimentally Hyperthyroid and Hypothyroid Rat

Apoptosis plays a critical role in the development and homeostasis of multicellular organisms, especially those with high cell turnover such as the lymphoid system. The current study aimed to examined the effects of changes in thyroid hormones on apoptosis of spleen in male rats. 30 rats were equally divided into three groups (10 animals each). G1, control group in which animals did not received any treatment; G2, Hypothyroid group in which rats received 0.05% 6-n-propyl-2-thiouracil (PTU) in drinking water for 6 weeks; G3, Hyperthyroid group in which rats received 100 μg/Kg L-Thyroxin sodium administration in drinking water for 6 weeks. In the present study; serum T3 and T4 concentrations were depressed and serum TSH concentration was significantly elevated in rats receiving PTU-induced hypothyroidism. On the other hand; serum T3 and T4 concentrations were significantly elevated and serum TSH concentration was depressed in rats receiving L-Thyroxin sodium-induced hyperthyroidism. In the current study; spleen in both hypothyroid and hyperthyroid rats revealed many of abnormalities as marked disruption of spleen structure, loss in distinction between the white and red pulps, degeneration and vacuolation with an increased in the lymphocyte population. Also, a significant increase in p53 and Caspase3 apoptotic cells and a significant decrease in Bcl-2 antiapoptotic cells in the spleen tissues revealed the possibility of the apoptosis occurrence after PTU or Thyroxin administration in the case of hypothyroidism and hyperthyroidism.