Influência de um complexo vitamínico (ácido ascórbico, alfa-tocoferol e beta-caroteno) no estresse oxidativo de células mononucleares de indivíduos não diabéticos e diabéticos tipo 1

Abstract

Diabetic patients are exposed to increased oxidative stress due to several mechanisms, mainly hyperglycaemia. Pathological processes, such as those in type 1 diabetes, include diminished activity of the antioxidant defense system(s) or excessive oxidative generation resulting in an oxidative/antioxidant imbalance and development of oxidative stress. The purpose of this study was to evaluate the production of reactive oxygen species (ROS) (chemiluminescence) and reduction capacity (MTT dye reduction), superoxide dismutase and catalase using quantitative reverse transcriptase polymerase chain reaction the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, the levels of cytokines [interleukin (IL)-6, tumour necrosis factor-, IL-8, IL-10 and IL-4] by sandwich enzyme-linked immunosorbent assay and ROS production with inhibition of signaling pathways in mononuclear cells from non-diabetic and diabetic donors treated with a vitamin complex (ascorbic acid, -carotene and -tocopherol) in two different concentrations ([A]=ascorbic acid=0.08 M, -tocopherol=0.04 M, -carotene=0.0008 M and [20A]=ascorbic acid=1.6M,-tocopherol=0.82M, -carotene=0.016 M). Concentration [A] was antioxidant reducing expression of NADPH oxidase subunits while raising the expression of antioxidant enzymes and reducing pro-inflammatory cytokines in both groups. Concentration [20A] was pro-oxidant by raising ROS production, NADPH oxidase subunits and pro-inflammatory cytokines and reducing antioxidant enzymes and anti-inflammatory cytokines in the non diabetic group but antioxidant in cells of type 1 diabetic patients by raising antioxidant enzymes and anti-inflammatory cytokines and reducing proinflammatory cytokines. ROS production raised with signaling pathway inhibition plus [A] for AKT/PKB, PKC, p38MAPK and PKA and plus [20A] for PKC and p38MAPK in non- diabetic. In diabetic cells ROS production raised with inhibition of PKC, p38MAPK and PKA with [A] and PKC and p38MAPK with [20A]. ROS production reduced inhibiting AKT/PKB and [20A] in diabetic cells. The vitamin complex has a dual effect, pro-oxidant and antioxidant, being also dose dependent with different profiles of cells of non-diabetic and type 1 diabetic patients.