Abstract
Purpose: :
Due to the obesity epidemic, diabetic retinopathy (DR), the most common complication of diabetes, affects a growing number of Americans each year. Current ablation treatments are invasive, costly and do not improve vision. Consequently, less invasive, preventative measures are increasingly necessary. Characterized by vessel loss and subsequent pathological neovascularization (NV) in the retina, DR is associated with hyperglycemia as well as dyslipidemia. We previously found that ω-3 long chain polyunsaturated fatty acids (PUFAs) reduced retinal NV compared to ω-6PUFAs in a mouse model of oxygen-induced retinopathy (OIR), which mimics the proliferative stage of DR. The link between DR and abnormal lipid metabolism raises the possibility that the protective effect of an ω-3PUFA-rich diet may extend to a mouse model of type II diabetes mellitus (T2DM), which is the aim of this study.
Methods: :
Leptin-receptor deficient type II diabetic mice (db/db) were fed a defined diet with a 2% enrichment in either ω-3 or ω-6PUFAs for 22 weeks. Visual function was measured at 9, 14, and 26 weeks by electroretinography (ERG). Retinal capillary, neuronal integrity, and glucose stress response were assessed for each diet. Expression of inflammatory mediators was analyzed with RT-PCR.
Results: :
ERG measurement showed that ω-3PUFAs significantly preserved retinal function in the mouse model of type II diabetes to levels similar to those observed in nondiabetic control mice on normal chow. Conversely, retinal function gradually deteriorated in db/db mice on a ω-6PUFA rich diet. In addition, there was an enhanced ability for ω-3PUFA-fed mice to respond to glucose challenge. There were no significant differences in retinal vasculature, retinal ganglion cell (RGC) numbers, or inflammatory mediatory levels between the ω-3PUFA-fed and ω-6PUFA-fed mice, suggesting that the protection of visual function was independent of cytoprotective or anti-inflammatory effects of ω-3PUFAs.
Conclusions: :
The results from this study suggest that an ω-3PUFA-rich diet is beneficial in preserving retinal function in a mouse model of T2DM. Moreover, dietary supplementation of ω-3PUFAs may represent a safe, inexpensive means of slowing the progression of vision loss in T2DM.
Keywords: diabetic retinopathy • lipids • electroretinography: non-clinical