# Biochemical Study of Bilberry Extract Potential in Preventing Retinal Damage in Rat Model of Diabetes Induced by Streptozotocin/Nicotinamide

## TL;DR

This study shows that bilberry extract may help reduce retinal damage caused by diabetes in rats by lowering oxidative stress and improving certain biomarkers.

## Contribution

The novel contribution is demonstrating bilberry extract's potential to mitigate oxidative retinal damage in a rat model of diabetes.

## Key findings

- Bilberry extract significantly reduced retinal lipid peroxidation and advanced oxidized protein products in diabetic rats.
- Treatment normalized the expression of VEGF and MMP-9, which are linked to vascular changes in diabetic retinopathy.
- Bilberry extract partially improved lipid profile by lowering LDL cholesterol levels in diabetic rats.

## Abstract

Type 2 diabetes mellitus is a growing global health concern, with diabetic retinopathy (DR) representing a major microvascular complication that contributes significantly to vision impairment. Oxidative stress plays a critical role in the pathogenesis of DR, which is associated with changes in vascularization-associated molecules, such as iNOS, VEGF, and MMP-9. The present study investigates the therapeutic potential of bilberry (Vaccinium myrtillus L.) extract—rich in anthocyanins—applied for 14 days on blood glucose levels, lipid profile, and retinal oxidative stress (lipid peroxidation (TBARS) and advanced oxidized protein products (AOPPs)) in a streptozotocin/nicotinamide (STZ/NA)-induced diabetes rat model. Results showed a significant reduction in non-fasting blood glucose, retinal TBARS, and AOPP levels, and normalization of VEGF and MMP-9 expression in bilberry-treated diabetic rats. Bilberry extract also partially improved lipid profile by lowering LDL levels. However, no significant effects on fasting glucose or serum insulin were observed. These findings suggest that bilberry extract may offer protective effects against oxidative retinal damage and could serve as a complementary approach in managing early diabetic retinopathy.