Garlic extract (Allium sativum L.) attenuates neurodegeneration and microvascular damage in rats with streptozotocin-induced diabetic retinopathy

• GE attenuates the degeneration of retinal neurons and microvasculature unit of the retina. • GE restores retinal thickness and cell diameter and count, preventing neuronal loss. • GE protects vascular density and main artery diameter, restoring retinal arterioles. • Garlic supplements could mitigate diabetic damage and promote retinal regeneration. Diabetic retinopathy (DR) is a severe complication of diabetes mellitus (DM). Despite numerous studies exploring the anti-diabetic properties of garlic in managing DM symptoms, its impact on DR remains limited. This study aimed to test the effectiveness of garlic in managing DR in a streptozotocin-induced DR rat model. Rats were divided into three groups: normal control (NC), diabetic control (DC), and diabetic group (DG) treated with aqueous garlic extract (GE). Histological examination revealed a significant reduction in retinal thickness in DC rats compared to that in DG rats, which showed restored retinal thickness similar to the NC group. Immunohistochemical analyses revealed significant improvements in retinal vascular density, main artery diameter, and blood vessel numbers in DG rats compared to DC rats. The findings suggest that GE protects against DR. Furthermore, garlic could be recommended as a beneficial dietary supplement for diabetic patients to manage and delay the progression of DR.