Abstract
Purpose :
To evaluate the longitudinal in-vivo endoplasmic reticulum (ER) stress activated indicator (ERAI) reporter mouse for retinal degeneration and fundus autofluorescence.
Methods :
We compared ERAI mice mated to RhoP23H mice expressing ER stress-inducing misfolded rhodopsin with ERAI mice mated to Tulp1 wildtype (WT) mice. With a total of n= 30 mice, both genotypes were imaged at P30, P60, and P120. Confocal scanning laser ophthalmoscopy (cSLO), blue autofluorescence (BAF), and infrared autofluorescence (IRAF) imaging was performed with focus on retina. The BAF was quantified by calculating corrected mean fluorescence (A.U.) in ImageJ. Optical coherence tomography (OCT) imaging was performed with a 55o retina lens to obtain 3-D volumetric scans. OCT thickness heat maps were generated using Bioptigen software to obtain all 8-layers thickness of retina. Statistical comparisons were made using Student’s t-test with significance at P < 0.05, 95% CI.
Results :
The ERAI;RhoP23H/+ retinas showed significantly increased BAF and IRAF signal at P30, P60, and P120, when compared with ERAI;Tulp1+/+ retinas. The mean total retinal thickness was significantly decreased for ERAI;RhoP23H/+ when compared with ERAI;Tulp1+/+ at P30 (201 µm), P60 and P120 (161 µm) time points. The BAF increase indicates increased ER stress while the OCT thickness decrease indicates retinal degeneration.
Conclusions :
ERAI reporter mice allow for longitudinal studies of ER stress in living mouse eyes as ERAI;RhoP23H/+ showed significant ER stress and retinal degeneration as a function of time and disease progression. A real-time, longitudinal evaluation of ERAI mice mated to tulp1-/-, tulp1D94Y and tulp1F491L, novel models of retinal degeneration undergoing ER stress, is ongoing.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.