Abstract
Purpose :
Experiments were performed to demonstrate pERG and pVEP recovery in glaucoma-induced mice after generation of new RGCs following PNU-282987 treatment.
Methods :
Both sexes of adult mice (3-6 months) were injected with 1.2 M hypertonic saline into the episcleral vein to increase IOP as previously reported to induce glaucoma-like conditions. After the procedure, mouse eyes were treated once daily using eye drops containing 1mM PNU-282987/1mg/ml BrdU. Weekly pERGs and pVEPs were recorded using the Celeris Diagnosys System. At specified time points, animals were euthanized, retinas were removed, processed immunocytochemically with antibodies against BrdU and Thy 1.2 and imaged. Data was analyzed with ANOVA. Significance = P<0.05. N’s of 3-12 were obtained for each condition.
Results :
In glaucoma-induced mice, an average of 25.88% (±3.4) RGCs were lost after 1 month. After agonist treatment following the procedure, Thy1.2/BrdU+ neurons appeared in the GCL. PNU-282987 significantly reduced the loss of Thy1.2+ cells associated with the glaucoma procedure to an average of 10.4% (±2.8) compared to what is typically lost within a month. To assess the function of RGCs, PhNR and pERG were obtained. In flash ERGs, the amplitude of the photopic negative response (PhNR) decreased by 71.5% (±6.2) after the glaucoma procedure unless treated with PNU-282987. When treated with the agonist for 1 month, the amplitude of the PhNR significantly recovered by 90% (±20.5). The average P1 amplitude of recorded pERGs in dark-adapted mice decreased by an average of 69.4% (±7.2) 1 month after glaucoma induction. With agonist treatment, the P1 amplitude significantly recovered by an average of 40% (±4.4) within a month after inducing glaucoma. The average N2 amplitude of the pERG decreased by 56% (±3.4) after inducing glaucoma. However, with agonist treatment, the N2 amplitude recovered by an average of 34% (±2.9). When assessing cortical function, the average amplitude of the main negative component of the pVEP decreased by an average of 44.2% (±5.3) 1 month after inducing glaucoma. However, with agonist treatment, the pVEP negative amplitude significantly recovered by 56% (±3.6) a month after the procedure.
Conclusions :
Results from this study support the hypothesis that PNU-282987 treatment can elicit new RGCs that lead to functional changes in the retina and visual cortex.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.