The Concomitance of Diabetes and Hypertension Leads to Cell Proliferation Arrest in Adult Rat Retina

Abstract

Methods:: Twelve week-old spontaneously hypertensive (SHR) and their normotensive control WKY rats were rendered diabetic by injection of streptozotocin. After 15 days, rats were sacrificed and the retinas were collected.

Results:: The number of BrdU positive cells in the retina assessed by 5-bromo-2’-deoxyuridine (BrdU) immunofluorescence was significantly higher in SHR than in WKY (p=0.01). After 15 days of induction of DM, there was a marked reduction in cell replication only in diabetic SHR rats (p=0.007). The retinal expression of p27Kip1in inner nuclear layer was increased in diabetic SHR (p=0.02). There was a marked increment of VEGF protein expression in diabetic SHR (p=0.02) accompanied by a marked blood-retinal barrier (BRB) breakdown (p=0.01).

Conclusions:: The concomitance of diabetes and hypertension markedly decreased the replicative capacity of the retinal cells associated with elevation of p27 Kip1 and VEGF retinal expressions and the breakdown of BRB. Further studies are in current investigation in order to identify the retinal cell type in proliferation.

Clinical Trial:: 67980

Keywords: diabetic retinopathy • immunohistochemistry • retinal glia