Associação entre estresse oxidativo, estabilidade de membrana de eritrócitos e jetlag social em trabalhadores em turnos

Abstract

Introduction: Shift workers are individuals vulnerable to the circadian misalignment that occurs because of the divergence between the biological clock and social and labor obligations, such as shift work. Social Jetlag (SJL) - defined as a measure of circadian system rupture - is usually elevated in shift workers and is associated with metabolic and cardiovascular diseases in different population groups. However, the effects of SJL and work shift on oxidative stress and osmotic membrane stability of erythrocytes of shift workers are still unexplored in the literature. This is an important issue to be addressed, since both oxidative stress and osmotic stability of erythrocyte membrane are involved in several pathophysiological processes. Objective: To evaluate the association among work shifts, social jetlag, sleep hours parameters of oxidative stress damage, antioxidant defense and membrane stability in shift workers. Materials and Methods: This was a cross-sectional study of 79 men aged 21-65 years and mean BMI of 27.56 (± 4.0), who worked at night shift (n = 37) and daytime (n = 42). The oxidative stress markers (TBARS, Carbonyls, Hydrogen Peroxide - H2O2 - and Nitrites), antioxidant defenses (FRAP, Superoxide dismutase, Catalase and Glutathione) were analyzed in the blood samples (weight, height and waist circumference) peroxidase), erythrocyte membrane stability and biochemical stability parameters - maximal absorbance (Amax), minimum absorbance (Amin), saline concentration involved in the hemolysis process (dX) and saline concentration where the hemolysis was 50 % (H50). SJL was calculated by the absolute difference between the midpoint of sleep on work and rest days. Results: In the study that evaluated the oxidative stress, we verified that the nocturnal group had higher values of TBARS and H2O2 in relation to the diurnal ones. The nocturnal group also presented lower values of nitrite, FRAP, catalase and superoxide dismutase. In addition, a negative association was found between SJL and the catalase and superoxide dismutase enzymes. In the study that involved the evaluation of membrane stability, it was observed that individuals who slept on average less than 6 hours presented higher values of 1/H50 and dX. Interaction between shift and SJL was also found for the variable Amin, in which the night shift and without SJL individuals presented lower values in relation to the others. Conclusion: Our findings suggest that the nocturnal worker has higher levels of oxidative stress and lower levels of antioxidant defenses, and SJL is possibly one of those responsible for this condition. In addition, the erythrocyte membrane stability seems to be influenced by sleep hours and social jetlag.