Influence of hypothyroidism on the level of 8-hydroxy-2’-deoxyguanosine as a biomarker of oxidative damage in comorbid conditions

Abstract

Objective — to evaluate the hypothyroidism effects on the level of 8-hydroxy-2’-deoxyguanosine (8-OHdG) as a biomarker of oxidative damage in the comorbid course of hypertension (H), type 2 diabetes mellitus (DM2T) and subclinical hypothyroidism (SH).Materials and methods. 89 patients (28 males and 61 females) aged 40 to 75 years with stage II H and DM2T in the compensation were divided into groups: group 1 included subjects with normal thyroid function (n = 48), group 2 consisted of patients with SH (n = 41). The control group involved 20 healthy volunteers. The anthropometric indices, lipid, carbohydrate and thyroid metabolism, ultrasound examination of the thyroid gland have been studied. The determination of serum 8-OHdG was performed by the method of enzyme immunoassay.Results and discussions. Level of 8-OHdG in both group 1 and group 2 was more than 2-fold, than in the control group, but differences between the groups were insignificant (p > 0.05). After the re-allocation of patients from 2 groups in two subgroups, depending on the level of TSH: 2a — TSH up to 5.5 µIU/ml, (n = 19); 2b — TSH from 5.6 to 10 µIU/ml, (n = 22), the significant differences in the level of 8-OHdG between 2a and 2b subgroups were established: (13.14 ± ± 0.62) ng/l and (15.59 ± 0.53) ng/l respectively, (p < 0.05). Correlation analysis revealed a positive correlation between TSH levels and 8-OHdG (p = 0.015, r = 0.550) in 2nd group.Conclusions. The presence of a combined course of H and DM2T was characterized by a significant increase in the serum 8-OHdG levels as compared to the healthy volunteers. The addition of SH was characterized by a raise of DNA oxidative damage, which increases with the TSH increasing.