Inhibitory Effects On Retinal Neovascularization by Ranibizumab and sTie2-Fc in An Oxygen-Induced Retinopathy Mouse Model

ABSTRACT

Purpose: To study retinal neovascularization (RNV) inhibition by intravitreal injections (IVs) of ranibizumab, sTie2 fusion protein (sTie2-Fc), and a combined therapy in an oxygen-induced retinopathy (OIR) model.

Materials and methods: An OIR mouse model was used to simulate RNV in retinopathy of prematurity (ROP); and the effect of blocking the angiopoietin (Ang) and its receptor (Tie2) and the vascular endothelial growth factor (VEGF) and its receptor (VEGFR) signaling pathways was compared using an IV of sTie2-Fc (Ang inhibitor) and/or ranibizumab (aVEGF antagonist). The effects were assessed using fluorescein isothiocyanate (FITC)-dextran cardiac perfusion, isolectin B4 (IB4) staining with whole retinal mounting, and hematoxylin and eosin (HE) staining to count the endothelial cells (ECs) that broke through the internal limiting membrane (ILM). The mRNA and protein levels of VEGF-A, VEGFR-2, Ang1, Ang2, and Tie2 were also determined by reverse transcriptase polymerase chain reaction (RT-PCR) and western blot analysis.

Results: Compared with the control group injected with phosphate-buffered saline (PBS), all three experimental groups, ranibizumab, sTie2-Fc, and ranibizumab + sTie2-Fc, had a significant decrease in micro-vessel densities and neovascular clusters, and fewer ECs broke through the ILM (all p < 0.05). The non-perfusion areas decreased in both mono-treated groups, although the combined therapy had larger non-perfusion areas. All three treatments decreased the mRNA and protein levels of VEGFA, Ang1, and Tie2.

Conclusion: In this study, it was confirmed that blocking the Ang/Tie2 and/or VEGF/VEGFR pathways could inhibit RNV and decrease abnormal micro-vessel density; and the mono-blockage of Ang/Tie2 might cause a smaller non-perfusion area.

KEYWORDS:

• Retinal neovascularization
• oxygen-induced retinopathy model
• non-perfusion area
• ranibizumab
• sTie2-Fc

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This work was sponsored by the Natural Science Foundation of Shanghai [17ZR1404500].

Notes on contributors

Xin Huang

Xin Huang, Chen Jiang, and Lu Ruan intellectually conceived and supervised the research, analyzed the data, and wrote the manuscript. Chen Jiang, Lu Ruan, and Juan Zhang performed the experiments and analyzed the data. All authors provided final approval of the submitted manuscript.