Abstract
Purpose: :
Diabetes and its complications are multifactorial diseases with various abnormalities contributing to its development and therefore an appropriate therapy would have to modify all these abnormalities. With respect to diabetic retinopathy (DR), the notion that it is solely a microvascular complication has been challenged in recent years, is also shown to have an inflammatory and a neurodegeneratve component. Our purpose was to test in an animal model of DR substances with three properties: 1) the ability to regulate the expression of VEGF, 2) neuroprotective capacity and 3) anti-inflammatory properties. In this regard, we propose to study the effect of docosahexaenoc acid (DHA) in DR.
Methods: :
Animals were treated in accordance to the ARVO statement for the use of animals in ophthalmic and vision research. Male, Wistar rats were used in the study. Diabetes was induced in animals by a single intraperitoneal injection of streptozotocin (STZ) (65 mg/ kg. After 4 weeks a group of control and diabetic animals were sacrificed and retina was extracted. The rest of the rats were divided into the following experimental groups: control rats; control rats treated with DHA (13.3 mg/kg orally); diabetic rats and, diabetic rats treated with DHA. Rats received treatment from week 4 of the experiment till week 12. At the end of week 12, rats were sacrificed. Prior to sacrifice, electrorretinogram was performed. Retinas were homogenized in prechilled 0.2 M potassium phosphate buffer,pH 7.0. This homogenate was used to assay, VEGF, inflammatory markers (Il-1a, IL-1B, IL-2, TNFα, etc) and oxidative stress related parameters. Statistical significances were assessed by means of the Student’s t-test.
Results: :
After 12 weeks of diabetes, changes in VEGF and inflammatory and oxidative markeres were observed, and were more evident that after only 4 weeks of diabetes. b-wave amplitude was decreased and b-wave implicit and latency time was decreased after 12 weeks of diabetes. The treatment with DHA, that started after 4 weeks of diabetes, when some changes were already observed in the retina of diabetic animals, partially reversed the changes mentioned aboved.
Conclusions: :
DHA appears a good coadjuvant therapeutic aproach to reverse changes observed in diabetic retina.
Keywords: diabetic retinopathy • electroretinography: non-clinical • oxidation/oxidative or free radical damage