Neuropilin-1 (NRP-1) is a transmembrane
glycoprotein. As a
VEGF co-receptor, NRP1 significantly enhances VEGFR2 signaling and promotes vascular permeability and migration. The purpose of this study was to evaluate the effects of an NRP-1 inhibitor,
ATWLPPR peptide, on the early stages of
diabetic retinopathy. Eight-week-old male C57BL/6 mice were divided into three groups: a Normal group, a Diabetes (DB) ATWLPPR treatment group and a DB saline group. Electroretinography (ERG), fundus fluorescence angiography (FFA) and
leukostasis were examined to evaluate the
retinal injury induced by diabetes at the end of the fifth week after STZ injection.
Occludin expression and extravasation of
albumin were measured to determine the extent of
vascular injury. The oxidative stress level and the levels of
inflammation-associated
proteins were also assayed. The results indicated that treatment with ATWLPPR prevents the abnormal condition of ERG (amplitudes of b-wave decreased and implicit time increased) and
vascular injury (
occludin degradation and increase in extravasated
albumin). These effects were associated with a reduction in the
oxidase stress level and the expression of
VEGF, GFAP, and
ICAM-1. We conclude that ATWLPPR, an NRP-1 inhibitor, may reduce the early
retinal damage induced by diabetes by preserving vascular integrity and decreasing the oxidative stress level. Blockade of NRP-1 may be a new therapeutic strategy for the early stages of DR.