Age-dependent changes in the severity of capillary degeneration in rat retina following N-methyl-D-aspartate-induced neurotoxicity

Abstract

Purpose: Previous studies have shown that injury to the retinal vasculature, including capillary degeneration, occurs following N-methyl-d-aspartate (NMDA)-induced neuronal cell loss, but it is unclear whether there are age-dependent differences in the severity of vascular damage. The purpose of the present study was to determine age-related changes in retinal capillary degeneration in NMDA-induced retinal damage rat model.

Materials and methods: A single intravitreal injection of NMDA (200 nmol/eye) was performed in 1-, 2-, 3-, 7- and 15-week-old male Sprague-Dawley rats. Seven days after NMDA injection, damage to retinal neurons and blood vessels were assessed by measuring the number of cells in the ganglion cell layer and the length of empty basement membrane sleeves, left behind by regressing endothelial cells, respectively.

Results: At all ages examined, the NMDA-induced neurotoxicity exhibited similar levels of ganglion cell death. However, the degeneration of capillaries in NMDA-treated retina was severe during the early stages of retinal vascular development, and the degree of capillary degeneration decreased with age.

Conclusion: The degree of retinal capillary degeneration in NMDA-induced retinal damage rat model decreases in an age-dependent manner. Retinal capillaries may be resistant to retinal neuronal damage in young adults.

Keywords: Age; endothelial cells; excitotoxicity; retinal blood vessels; retinal neuronal cells.