Abstract
Purpose :
Increased inflammatory factor level has been reported in vitreous humor of diabetic retinopathy and macular edema, however, the inflammatory mediator concentrations are unexplored in retinal degenerations without neovascularization. Human retinal dystrophies and degenerations and light-induced retinal degeneration (LIRD) in animal models share several features, such as photoreceptor death and retinal inflammation. Here, we aimed to determine the inflammatory factor concentration in the vitreous humor of LIRD mouse model.
Methods :
LIRD was induced by exposing BALB/c mice to white light (15,000 lux, 2h), and mice were recovered for 2 days before analysis. Optical coherence tomography (OCT) and hematoxylin and eosin (HE) staining accessed retinal morphology, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) determined retinal cell viability, electroretinogram (ERG) measured retinal responses. Total retinal RNAs were extracted and subject to RNA-sequencing analysis. The vitreous humor was obtained by using a Hamilton needle, with a volume of 3~5 μl obtained from each eye. Vitreous humor from control (n=4) and LIRD mice (n=9) were assayed in triplicates for a panel of 4 inflammatory mediators using the Simple Plex Cartridge on an Ella System. Data were acquired on Simple Plex Explorer .
Results :
Retina degeneration, photoreceptor death, infiltration of microglia/macrophages into the photoreceptor layer and loss of a-wave and b-wave were detected after LIRD. RNA-sequencing revealed LIRD led to significant upregulation of inflammatory factors in mouse retinas, such as complement factor (C3), chemokines (CCL2, CCL2, CCL4), interleukin (IL1b) (n=4 per group, P<0.05). In the control mice, the mean concentration of CCL2, IL6, IL1β and TNFα in the vitreous humor were 118.4±104.8, 1.7±1.2, 9.6±6.8, and 3.1±2.1 pg/ml, respectively. After LIRD, the concentration of CLL2 (3000.9±1077.0 pg/ml) and IL6 (9.5±4.1 pg/ml) were significantly increased (P<0.005). Increased although not significantly TNFα (12.6±11.0 pg/ml) and IL1β (42.3±60.5 pg/ml) were also detected in vitreous humor after LIRD.
Conclusions :
LIRD induced inflammatory factor expression in both retina and the vitreous humor. Given the non-neovascular condition of this model, we propose increased inflammatory factors may present in the vitreous humor in retinal degenerations without neovascularization, such as dry age-related macular degeneration.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.