Evaluation of the effect of hypothyroidism on inflammatory cytokines stimulation associated with oxidative stress in Iraqi patients

The current study aims to evaluate the relationship of hypothyroidism to the stimulation of inflammatory cytokines and oxidative stress and to study the role of levothyroxine as a treatment for hypothyroidism and its effect in alleviating these side effects by raising the levels of thyroid hormones to the normal level. The study groups were distributed into three groups, two groups for hypothyroidism patients and one for healthy people. The first group (G1) was for healthy people, the second group (G2) was for hypothyroidism patients with treatment of levothyroxine according to the doctor's instructions, and the third group (G3) was for hypothyroidism patients who were without treatment and those who are newly diagnosed with hypothyroidism. Samples were collected, serum was obtained and tests were conducted for Thyroid Stimulating Hormone (TSH), and thyroid hormones Triiodothyronine (T3), and Thyroxine (T4) to diagnose the disease or not. Analysis of triglycerides(TG), cholesterol(TC), low-lipoprotein(LDL), high-density lipoprotein(HDL), and very low-density lipoprotein(VLDL) were performed, to evaluate the lipid profile of patients related to hypothyroidism. Antioxidant status has been evaluated by determination of Superoxide dismutase (SOD) and Catalase (CAT) as well as assessment of oxidative stress biomarkers such as Malondialdehyde (MDA), and Advanced oxidation protein products (AOPP). Levels of inflammatory cytokines C-reactive protein (CRP), and Tumor necrosis factor alpha (TNF-α) to evaluate its relationship to the progression of disease, and estimate the role of treatment in changing the levels of these biochemical factors in the group of patients receiving levothyroxine as therapeutic for hypothyroidism state. The results of the study showed increase significantly level of TSH in the patient groups compared to the control group (G1), but decreased values of T3 and T4 (P<0.001). a significant increase in body mass patient groups compared to control, as well as in the values of TC, TG, LDL, and VLDL concentrations but decrease in HDL level in patient groups compared to control (P<0.001). Increased level of oxidative markers Malondialdehyde (MDA), and Advanced oxidation protein products(AOPP) in patient groups (G2 and G3) compared to G1 (P<0.001), regarding the activity of antioxidant enzymes, it was found that there was a non-significant difference in the activity of superoxide dismutase between all groups but there is significantly increase the activity of catalase in patients groups compared to control ( P<0.001). Increased levels of inflammatory markers, Tumor Necrosis Factor Alpha (TNF-α), and C-reactive protein(CRP) significantly in patient groups compared to the control group (P<0.001). When comparing between the two groups of patients, there are also significant differences in the results. TSH level significantly decreased in G2 compared to G3. T4, and T3 increased in G2 compared to G3 (P<0.001). Oxidative stress ( MDA, AOPP) and inflammatory markers ( TNF-α, CRP) significantly decreased in G2 compared to G3 (P<0.001). Regarding antioxidant enzyme activities, CAT activity decreased significantly (P<0.001) in G2 compared to G3 but there are no significant differences in SOD activity. The results show the extent of the positive effect of treatment, not only in enhancing thyroid hormone levels, but also in helping reduce the effect of oxidative stress and inflammation that may occur as side effects of the disease by reducing the levels of inflammatory cytokines, despite not reaching the ideal condition, as was seen in the results of the healthy group.