Tissue specific oxidative stress profile in relation to glycaemic regulation in mice.

Background: Diabetes mellitus is a metabolic disorder characterized by hyperglycaemia resulting from uncontrolled glucose regulation. Reactive oxygen species are recognized as one link between hyperglycaemia and diabetic complications. Studies have shown that diabetes mellitus is associated with decreases in antioxidant potential and increased formation of free radicals leading to oxidative stress. The present study was undertaken because an unequivocal demonstration that control of hyperglycaemia can reduce oxidative stress is still lacking.

Methods: In the present study, we investigated oxidative stress profile of normal, streptozotocin-induced diabetic, insulin-treated and untreated diabetic animals. On the one hand, oxidative damage caused to lipids, proteins and DNA was measured. On other hand, antioxidant defense was measured in terms of specific activities of antioxidant enzymes (AOEs) and antioxidant molecules.

Results: It was observed that the damage to lipids, proteins and DNA caused by free radicals increased in diabetic animals compared with that in controls. In diabetic animals not treated with insulin, damage to all biological molecules increased further significantly (p ≤ 0.005). Changes in AOEs from different tissues were complex depicting a varied AOE level in different tissues. Insulin treatment significantly improved the oxidative stress profile in all tissues studies.

Conclusions: The control of hyperglycaemia improves oxidative stress profile, that is, the ability of cells to cope up with oxidative stress.