Avaliação da retinopatia diabética em ratos induzidos pela estreptozotocina após tratamento com melatonina

Abstract

Diabetic retinopathy is a metabolic disease with cardiovascular involvement with high risk of vision loss. It causes structural and functional damage to the retina increases the expression of inflammatory cytokines (IL-6 and TNF-α) and induces pathological intraocular neovascularization. The aim of this study was to evaluate the effect of melatonin on histopathology, oxidative stress (retina and pancreas) and electrical retinal activity and if she would be able to mediate the expression of VEGF, IL-6 and TNF-α, in addition to index apoptotic. We used 50 rats divided into the following groups: GC: no induction mice diabetes by streptozotocin; GD: rats with diabetes induced by streptozotocin treated and placebo; GDM: rats by streptozotocin induced diabetes mellitus and after confirmation treated with melatonin at dosage of 10 mg / kg body weight for 20 days; GDMS: mice induced by streptozotocine diabetes and simultaneously treated with melatonin at dosage of 10 mg / kg for 20 days; GDI: rats by streptozotocin induced diabetes mellitus and after confirmation treated with insulin for 20 days. Diabetes was induced by intraperitoneal administration of streptozotocin (60mg / kg), melatonin was administered subcutaneously at night, and insulin (5U / day) by the same route. For apoptosis was performed TUNEL assay and immunohistochemistry targets were analyzed for IL-6, TNF-α and VEGF. The pancreatic oxidative stress was assessed by measurement of lipid peroxidation and reduced glutathione levels while stress in the retina was analyzed for the production of superoxide anions. The results showed that melatonin attenuated histopathological changes; decreased inflammation and regulated the mechanisms that caused oxidative stress and electroretinography interfere with the amplitude of the wave of the joint examination between the GC and GD groups. It is concluded that this hormone may be an important contributing factor in the treatment of diabetic retinopathy due to its antioxidant property and modulating inflammatory processes, softening the changes of this pathology, especially when administered concurrently with diabetes induction it was observed a significant improvement retinal preservation in increased serum insulin and decreased hyperglycemia.