Swept-Source Optical Coherence Tomography Angiography for Retinal Neurovascular Structural Evaluation in a Chronic Unpredictable Mild Stress Rat Model

The purpose of this study was to evaluate the retinal thickness and vascular changes in a chronic unpredictable mild stress (CUMS) rat model using swept-source optical coherence tomography angiography (SS-OCTA). Eight-week-old male Sprague Dawley rat models of CUMS (n = 11) and age-matched control rats (n = 12) were imaged by a customized SS-OCTA system. Two groups were imaged after modeling stimulation for 12 weeks. Retinal layer thicknesses were measured and compared using images and histological examinations. En face angiograms of the superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP) were analyzed for vessel density and diameter. CUMS rats exhibited significant thinning of the retinal nerve fiber layer (RNFL), inner retina, and total retina, particularly in the papillary and parapapillary regions and the superior and nasal quadrants. Histological analysis confirmed these findings. Vessel density reduction and vascular narrowing were evident, with SVP and ICP densities notably decreased, especially in the superior and temporal regions. Strong correlations were observed between trilaminar plexus density and inner retina thickness, particularly in SVP (P < 0.001) and ICP (P < 0.001). The OCTA imaging enables noninvasive visualization of neurovascular changes in rodent models, revealing retinal thinning linked to vascular degeneration, especially in SVP and ICP. Investigating the neurovascular structural changes of CUMS rats can provide animal experimental evidence for chronic stress as the basis for the onset of various eye diseases and also provide ideas for the daily emotional management of patients with clinical eye diseases.