Abstract
Purpose :
Diabetic retinopathy (DR) is characterized by retinal neurodegeneration and micro-vascular abnormalities. We previously showed the protection of retinal ganglion cells (RGCs) in two rodent models of glaucoma by intraperitoneally injected peptain-1. Here we evaluated the ability of intravitreally injected peptain-1 in protecting RGCs and retinal capillary cells in mice subjected to retinal ischemia/reperfusion (I/R) injury.
Methods :
Human retinal endothelial cells(HRECs) were treated with peptain-1 or a scrambled peptide (200 μg/ml) for 3 h, and a combination of inflammatory cytokines [IFN-γ 50U/ml +TNF-α 20ng/ml + IL-1β 20ng/ml] for 20 h. I/R injury to the retina was induced in 12-week-old C57BL/6J mice by elevating the intraocular pressure to 120mmHg for 60 min followed by reperfusion. The animals were injected intravitreally with peptain-1 or scrambled peptide (0.5 μg in 1 μl of PBS) immediately after I/R, and after one week. The contralateral eyes were used as vehicle controls. The animals were euthanized on day 14 post-I/R injury. RGC numbers were counted in the retinal flatmounts by staining for Brn3a. Changes in the retinal capillaries were verified by staining elastase-digested retinal blood vessels using Periodic acid–Schiff stain.
Results :
Peptain-1 entered HRECs without any transfer reagents asobserved in western blotting. Peptain-1blocked cytokines-induced (caspase-3–mediated) apoptosis in HRECs but scrambled peptides did not. Intravitreally injected peptain-1 was distributed throughout the retina as observed in immunofluorescence. The I/R injury caused the loss of RGCs and retinal capillary cells. However, intravitreally injected peptain-1 protected these cells from I/R injury.
Conclusions :
Our study demonstrated that peptain-1 protects RGCs and capillary cells from I/R injuryand suggests that peptain-1 could be used as a therapeutic agent to prevent the death of RGCs and capillary cells in DR.
This is a 2020 ARVO Annual Meeting abstract.