Quantification of Photoreceptors' Changes in a Diabetic Retinopathy Model with Two-Photon Imaging Microscopy

Area of Science:

• Ophthalmology
• Neuroscience
• Diabetology

Background:

• Diabetic retinopathy (DR) is a leading cause of blindness.
• Retinal neurodegeneration occurs early in DR pathogenesis, preceding microvascular changes.
• Neuroinflammation is implicated in DR progression.

Purpose of the Study:

• To assess the impact of neuroinflammation on retinal photoreceptors (PRs) in diabetic rats.
• To investigate the relationship between PR size, retinal location, and visual function in diabetes.
• To evaluate the utility of two-photon microscopy for quantifying retinal inflammatory alterations.

Main Methods:

• Induction of diabetes in rats.
• Two-photon microscopy was used to image unstained retinal photoreceptors at various eccentricities.
• Measurement of photoreceptor transversal area as a marker of neuroinflammation.
• Calculation of maximum anatomical resolving power.

Main Results:

• Diabetic retinas showed significantly larger photoreceptor transversal areas compared to controls.
• Photoreceptor size changes and neuroinflammation were not uniform across the retina.
• Diabetic retinas exhibited significantly lower anatomical resolving power across all retinal locations.
• Two-photon microscopy provided high-resolution imaging for individual photoreceptor analysis.

Conclusions:

• Chronic retinal inflammation in diabetes leads to increased photoreceptor size and impaired visual function.
• Photoreceptor alterations in DR are location-dependent.
• Two-photon microscopy is a valuable tool for characterizing and quantifying neuroinflammation and retinal changes in DR.