Influence of hyperthyroidism on hepatic antioxidants and cytokines Levels: An Experimental Study

Objective: Thyroid diseases greatly affect the liver. Hyperthyroidism can affect the function of the liver. This study aimed to investigate the possible change of antioxidant and pro-inflammatory cytokines levels in liver tissue in hyperthyroid rats. Material and Methods: This study was carried out with 2 experimental groups. Hyperthyroid group was fed with 4 mg/kg L-thyroxine added standard fodder. Control group was fed with standard rat fodder. Liver selenium (Se) levels were measured by inductively coupled plasma optical emission spectrophotometer (ICP-OES). The antioxidant markers such as Selenoprotein P (SelP), and glutathione peroxidase (GPx), and the pro-inflammatory cytokines such as Interleukin (IL)-18, and Tumor necrosis factor-α (TNF-α) levels were studied in liver tissues by ELISA. All markers levels of liver samples were measured in tissue homogenates. Results: Se, SelP, and GPx levels of the hyperthyroidism group were lower than the control group. (p=0.038, p=0.046, p=0.008 respectively). There was a significant increase in IL-18 and TNF-α levels in hyperthyroidism group when compared to control group (p=0.002, p=0.023 respectively). There was positive correlation between FT3 and FT4, IL-18 and TNF-α (r=0.761, r=0.843, and r=0.826 respectively), but there was negative correlation between FT3 and Se, SelP, and GPx (r=-0.833, r=-0.754, and r=-0.778 respectively). Conclusion: Our findings showed that antioxidant marker levels were decreased, and pro-inflammatory cytokine levels were increased in liver tissues of hyperthyroid rats. These findings suggest that impaired antioxidant and pro-inflammatory status may play a role in liver pathogenesis due to hyperthyroidism.