A Mouse Model of Retinal Recovery From Photo-Oxidative/Photo-Inflammatory Injury: Nrf2, SOD1, DJ-1, and Parkin Are Not Essential to Recovery

Abstract

PURPOSE. To determine if there is structural and functional recovery of the retina from light induced retinal degeneration, and to evaluate the role of the oxidative stress response elements Nrf2, SOD1, DJ-1, and Parkin in such a recovery process. METHODS. Eyes from C57BL/6J (B6J) mice and from oxidative stress response-deficient strains of mice were treated with intense light using the fundus camera-delivered light-induced retinal degeneration (FCD-LIRD) model. Fundus photographs, optical coherence tomography (OCT) images, and electroretinography (ERG) responses were obtained before the injury, during the ''maximal injury phase'' (days 4-7) and during the ''recovery phase'' (days 14-16) post light exposure and were evaluated for retinal damage and assessed for evidence of recovery from the injury. RESULTS. We demonstrate that mice treated with a sub-lethal FCD-LIRD protocol show an initial acute retina injury phase peaking between days 4 to 7 followed by a recovery phase in which the outer retinal thickness/volume and retinal function partially recover. These observations are reproduced in B6J mice and in mice lacking oxidative stress response enzymes (SOD1, DJ-1, and Parkin) or the oxidative stress response master regulator Nrf2. CONCLUSIONS. Our data indicate that retinal recovery from injury can proceed via pathways that are independent from the common oxidative stress response elements Nrf2, SOD1, DJ-1, and Parkin. Furthermore, the model of retinal recovery from injury that we describe here mimics changes seen in a variety of clinical entities and may provide an excellent platform for dissecting general pathways of retinal recovery from sub-lethal injury.

Forward genetic analysis using OCT screening identifiesSfxn3mutations leading to progressive outer retinal degeneration in mice

“…Screening thousands of mice for phenotype-genotype associations on a continuous basis for a prolonged period requires efficient and reproducible assays/techniques. With this goal in mind, we tested the reproducibility of OCT measurements in SOD1/DJ-1/Parkin triple-knockout (TKO) mice, an established model for retinal degeneration (18,19), compared with B6J control mice over several days. Mice were imaged and OCT measurements done in a masked manner.…”

“…These images were analyzed to obtain measurements of the thickness of multiple retinal layers at the target location using the Freehand tool in ImageJ (https://imagej.nih. gov/ij/) as described previously (19). Three locations 200 μm apart and in the center of the image were measured for three parameters: BM_ELM, ONL, and BM_ILM.…”

“…ERG. ERG responses of the CRISPR/Cas9-mutated lines were recorded in 3-mo-old dark-adapted homozygous (Sfxn3 −/− ), heterozygous (Sfxn3 +/− ), and control (Sfxn3 +/+ ) mice, using a scotopic Ganzfeld ERG system (Phoenix Research Labs) as described previously (19), following protocols outlined by the manufacturer and detailed in SI Appendix, Materials and Methods.…”

Single Cell RNA Sequencing Analysis of Mouse Retina Identifies a Subpopulation of Muller Glia Involved in Retinal Recovery From Injury in the FCD-LIRD Model

“…The flow chart presented in Figure 1 shows the protocols and steps used in this work starting from the application of light injury to the analysis of single cell RNA-seq (scRNA-seq). Based on our prior studies, 33 , 34 , 43 , 44 we had determined that the FCD-LIRD model led to retinal light injury that could modulated be easily by modifying the intensity of the light stimulus. In this model, maximal injury as seen on fundus photos and OCT can be seen at approximately day 5 after injury.…”

Forward genetic screening using fundus spot scale identifies an essential role for Lipe in murine retinal homeostasis

“…After anesthetizing mice and pupil dilation (see above), we obtained OCT images from both eyes using a Micron IV-OCT2 (Phoenix-Micron, Inc). Images obtained as described before 64 were used to determine retinal thickness measurements. The thickness of several retinal layers was measured using Fiji/ImageJ (10.1038/nmeth.2019).…”