Avaliação do estresse oxidativo em mulheres diagnosticadas com hipotireoidismo primário

Abstract

Thyroid hormones regulate the body metabolism, with changes in cellular oxygen usage profile. As a result, there may be production of reactive oxygen species that induce oxidative stress and cellular dysfunction in various tissues. The study aims to evaluate the levels of oxidative stress in women diagnosed with primary hypothyroidism. The study included 25 female patients from the Endocrinology Clinic of the University Hospital Walter Cantídio (HUWC) in Fortaleza, Ceará, with primary hypothyroidism. Blood samples of patients were collected in the hypothyroid condition and euthyroid. We evaluated the thyroid hormone function, biochemical and haematological profile of patients, beyond the parameters of oxidative stress from measurements of malondialdehyde, nitrite/nitrate, superoxide dismutase and catalase. We observed a significant reduction of total cholesterol, HDL, LDL and triglycerides and leukocytes after correction of hypothyroidism. In relation to oxidative stress, there was a significant reduction of catalase activity (50,12 ±12,75 vs 63,77 ± 23,8 atv/min; p = 0.03) when we compared two moments. There was no change in nitrite / nitrate concentration (p = 0.18), malonaldehyde (p = 0.67) and superoxide dismutase activity (p = 0.93) when we analyzed the whole group. There was no significant difference in the concentration of malonaldehyde in both situations (P = 0.67). The concentration of nitrite / nitrate was increased in cases of hypothyroidism with metabolic syndrome (34.07 ± 10.89 Vs 30.12 ± 10.12, p = 0.03). These data suggest that hypothyroidism alters oxidative stress, and catalase activity is the most sensitive marker. When hypothyroidism occurs with metabolic syndrome, NO levels increase, suggesting different mechanisms in oxidative stress in these two clinical conditions.