Effects of Thyroid Dysfunction on Liver Tissue in Male Rats

Abstract

Forty males Wistar rats about 5 months old with average weight 250±10 gm were divided randomly into four equal groups and treated for 3months as following: First group(C)was given normal saline(0.09%) NaCl only as a control group. Second group (T1) was given Levothyroxine (LRX) (100 µg/kg b.w I/P). Third group (T2) was given Carbimazole (CBZ) (5 mg/kg). And fourth group was given mixed dose were given LRX (50 µg/kg b.w I/P) for 6 weeks and then given CBZ for other 6 weeks at dose (2.5 mg /kg b.w orally). At the end of the experiment, all animals were sacrificed and the weight of animal were taken, then blood samples were collected directly from the heart and serum samples were isolated to measure T3,T4 and TSH hormone. Samples of liver and thyroid gland were taken for histological study. The results of T3 hormones revealed a significant (P<0.05) decrease in serum T3 level in Carbimazole treated groups when compared with the control and levothyroxine-treated rats. On the other hand, levothyroxine caused a significant (P<0.05) increase in serum T3 level when compared with the control group. The results of T4 hormones reveals a significant (P<0.05) decrease in serum T4 level in Carbimazole treated groups when compared with the control group and levothyroxine-treated rats. While, levothyroxine caused a significant (P<0.05) increase in serum T4 level when compared with the control groups. For TSH hormones, the results showed there were a significant (P<0.05) rise in serum TSH level in Carbimazole treated groups when compared with the control group and levothyroxine-treated groups. While, levothyroxine caused a significant (P<0.05) decrease in serum TSH level when compared with the control groups. The histological sections for liver in control group revealed normal liver parenchyma and normal hepatocytes and sinusoids. Thyroid gland sections show there was normal histological structures. In T1 group, Liver sections showed there was single cell necrosis with focal mononuclear cells aggregation. Thyroid gland sections showed there was hyperthyroidism characterize by increase in the colloid resorption with vacuolation of the nuclei of epithelial cells that lining the follicles. In T2 group, Liver sections show there was apoptosis in hepatocyte with increase in the number of kupffer cells. Thyroid gland sections show there was hypothyroidism with congestion in the blood vessels. In T3, Liver sections show there was no clear lesion. Thyroid gland sections show there was active thyroid follicles with presence of resorption vacuoles and congestion blood vessels.