Abstract
Purpose :
As previously shown, a retinal ganglion cell loss and optic nerve degeneration could be detected in a βb1-CTGF mouse model. Aim of this study was to show degeneration of other cell types, like bipolar cells and photoreceptors, and changes in retinal function at various time points.
Methods :
Electroretinograms (ERG) were performed at βb1-CTGF- and wildtype (WT) mice at 10 (n=6/group) and 15 weeks of age (n=8/group). At both points in time, retinas were processed for immunohistology (n=7/group). Photoreceptors (rhodopsin, opsin) and bipolar cells (recoverin, PKCα) were quantified. Cells were analyzed by using ImageJ. At 15 weeks, quantitative real-time-PCR (qRT-PCR) analyses were performed (n=5/group).
Results :
At 10 weeks, the a- and b-wave-amplitude were comparable at a light intensity of 25 cd/m2between the βb1-CTGF- and the WT-group (p>0.05). Additionally, no changes were noted via immunohistology for bipolar cells and photoreceptors. However, at 15 weeks, the a-wave response, represented by the electrical output of photoreceptors, was decreased in βb1-CTGF-animals (143.3±27.5 µV; p=0.009) compared to WT (233.5±12.0 µV). The b-wave response, represented by the output of the inner nuclear layer, was also significantly decreased in βb1-CTGF-animals (367.1±70.0µV; p=0.007) compared to WT (600.7±25.8 µV). At 15 weeks, cone bipolar cell area was decreased in βb1-CTGF-mice (13.0±1.5 area [%]/section) in comparison with WT mice (21.2±1.7 area [%]/section; p=0.004). Likewise, the qRT-PCR showed a significant downregulation of RecoverinmRNA levels in βb1-CTGF-animals (0.37-fold expression; p<0.001). Furthermore, a significant downregulation of RhodopsinmRNA levels was noted in βb1-CTGF-animals (0.42-fold expression; p=0.003).
Conclusions :
In this study, we could show a functional loss of inner nuclear cells and photoreceptors in βB1-CTGF animals. In addition, a loss of cone bipolar cells and rods could be noted. In conclusion the βb1-CTGF mouse model gives the opportunity to study pathomechanism occurring in primary open-angle glaucoma.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.