Associação entre marcadores de estresse oxidativo e capacidade antioxidante em pacientes com catarata senil

Abstract

Oxidative damage to ocular structures can lead to structural and functional changes compromising the vision process, therefore, studies have pointed to oxidative stress as a key event in the formation and/or progression of cataracts. Considering the involvement of antioxidant nutrients in the physiological mechanisms of enzymatic and non-enzymatic defense of the lens, the aim of this study is to assess whether there is an association between serum levels of antioxidant micronutrients and oxidative stress markers with senile cataract. Methods: This is a cross-sectional study, including adults and elderly, of both sexes, with senile cataract and a control group without cataract. The lens was evaluated and classified according to the Lens Opacity Classification System (LOCS) III into Nuclear (NC), Cortical (CC), Posterior Subcapsular (PSC) and Mix cataracts. Vitamins A, C and E, selenium, glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) were dosed in all participants. Results: 42 participants with senile cataract and 40 controls were evaluated. A high prevalence of serum vitamin C deficiency (72.0%) was observed, being three times higher in participants with cataract when compared to controls (PR 3.5; CI: 1.4-8.6). Serum vitamin C level was lower among those with CC (1.0; IIQ: 0.5-1.8 mg/L), NC (1.6; IIQ: 0.5-3.6 mg/L) and Mix (1.2; IQI: 0.9-2.0 mg/L) compared to the control (2.6; IQI: 1.9-6 mg/L) (p=0.02). Lower selenium levels were found in CC (57.5; IQR: 53.0-74.6μg/L). There was no difference between groups regarding vitamins A and E, MDA and GSH-Px. Conclusion: We observed a relationship between the type of lens opacity and low serum levels of vitamin C and selenium. Vitamin C deficiency was associated with the presence of senile cataract, but not with serum markers of elevated oxidative stress.