Reduced light exposure mitigates streptozotocin-induced vascular changes and gliosis in diabetic retina by an anti-inflammatory effect and increased retinal cholesterol turnover

Area of Science:

• Ophthalmology
• Endocrinology
• Molecular Biology

Background:

• Diabetic retinopathy (DR) is a significant complication of diabetes, leading to vision loss.
• Current treatments for DR are limited in efficacy, highlighting the need for novel therapeutic strategies.
• Lifestyle modifications are recognized for their potential to delay or prevent diabetic complications.

Purpose of the Study:

• To investigate the impact of reduced daily light exposure on retinal vascular changes in a rat model of diabetes.
• To assess the effects of altered light cycles on inflammation, aquaporin-4 (Aqp4) expression, visual cycle, and cholesterol metabolism in the diabetic retina and retinal pigment epithelium (RPE).

Main Methods:

• Streptozotocin (STZ)-induced diabetes model in male Wistar rats.
• Groups included control, diabetic (DM), light-restricted (6/18h light/dark cycle), and diabetic with light restriction (DM+6/18).
• Assessment of retinal vascular abnormalities via lectin staining and gene expression analysis (qRT-PCR) for inflammation, Aqp4, visual cycle, and cholesterol metabolism markers.

Main Results:

• Reduced light exposure significantly alleviated retinal vasculopathy, gliosis, and inflammatory markers (IL-1, TNF-α) in diabetic rats.
• Perivascular Aqp4 expression was increased in diabetic rats with reduced light exposure.
• Genes involved in the visual cycle and cholesterol metabolism were upregulated in the RPE of the DM+6/18 group compared to the DM group.

Conclusions:

• Reduced light exposure mitigates vascular damage and gliosis in diabetic retinopathy.
• This protective effect is mediated by anti-inflammatory actions, enhanced retinal cholesterol turnover, and increased perivascular Aqp4 expression.
• Altering light exposure represents a potential lifestyle intervention for managing diabetic eye disease.