Endothelial response to ultraviolet A (UVA)-induced injury in a murine model of Fuchs’ endothelial corneal dystrophy (FECD)

Abstract

Purpose : Oxidative stress is important in the pathogenesis of FECD but most studies to date have only examined it in healthy animals. Mutations in COL8A2 are responsible for most early-onset FECD cases. Col8a2Q455K/Q455K (Q455K) mice demonstrated progressive guttae and corneal endothelial cell (CEnC) loss but their response to oxidative stress has not been elucidated. The purpose of this study was to determine the impact of UVA-induced injury in this FECD model.

Methods : Mice were imaged with in vivo confocal microscopy (IVCM) and optical coherence tomography (OCT) then UVA-injury was induced unilaterally at 50, 75, 125, and 250 J/cm2 (n = 4-5). On days 3, 7 and 10, endothelial cell density (ECD) and central corneal thickness (CCT) were measured. On day 14, immunostaining for ZO-1 and DAPI was performed on endothelial flatmounts. Data presented as mean±SD and compared with a two-way ANOVA and a post-hoc Tukey’s test.

Results : For the 250 J/cm2 exposure, CCT significantly increased from baseline (89±10 µm) to 126±24 and 184±39 µm on days 3 and 10, respectively (P<0.05). The ECD significantly decreased over time for mice exposed to 75, 125, and 250 J/cm2 (P<0.05) but did not significantly differ for the 50 J/cm2 exposure (P>0.133). Specifically, ECD decreased from a baseline of 1761±80 to 880±489 cells/mm2 at day 10 for the 75 J/cm2 exposure (P=0.026); a trend towards lower ECDs was observed for the 125 and 250 J/cm2 exposures at 60±135 and 174±388 cells/mm2, respectively. Endothelial flatmounts of Q455K mice exposed to 50 and 75 J/cm2 demonstrated severe and moderate CEnC pleomorphism and polymegathism in the center and periphery, respectively.

Conclusions : UVA-induced injury resulted in a profound decrease in ECD in Q455K mice compared with previously reported values for WT mice. These data suggest that CEnCs from Q455K mice are highly susceptible to UVA oxidative stress and further validate the utility of this early-onset FECD model for therapeutic interventions that target oxidative stress.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Fig 1. The Q455K mice exhibit marked CEnC changes following UVA injury. UVA irradiation at 250 J/cm2 induces a significant increase in CCT from baseline (A-E). A significant decrease in ECD occurred in all groups from baseline, except 50 J/cm2 (F-J). Central CEnCs (K,L) demonstrate greater pleomorphism and polymegathism versus peripheral ones (M,N).