Streptozotocin-induced diabetic mice exhibit reduced experimental choroidal neovascularization but not corneal neovascularization

The present study aimed to investigate the effects of diabetes mellitus (DM) on the generation of experimental corneal neovascularization (CrNV) and choroidal neovascularization (ChNV). Diabetes was induced in mice by intraperitoneal injection of streptozotocin (STZ). Experimental CrNV and ChNV were induced by alkali injury and laser photocoagulation, respectively. CrNV and ChNV were compared between the STZ-induced diabetic mice and control mice two weeks after injury. Relative expression of angiogenic factors was quantified by reverse transcription-quantitative polymerase chain reaction, and progenitor cell or macrophage accumulation in the early phase following injury was examined by flow cytometric analysis. Compared with the alkali-injured normal mice, the alkali-injured diabetic mice (STZ-induced) exhibited no significant difference in CrNV occurrence, whereas the laser-injured diabetic mice exhibited significantly reduced levels of ChNV compared with those of the laser-injured control animals. The laser-induced intrachoroidal mRNA expression levels of angiogenic factors, including vascular endothelial growth factor, hypoxia-induced factor-1α, chemokine (C-C motif) ligand 3, and stromal cell-derived factor-1α, were reduced in the laser-injured diabetic mice when compared with laser-injured control mice. Furthermore, the laser-induced intrachoroidal infiltration of c-Kit(+) progenitor cells was impaired in the laser-injured diabetic mice compared with the laser-injured control mice. Overall, diabetes did not exert a significant effect on the generation of experimental CrNV. However, diabetes reduced laser-induced ChNV through downregulation of intrachoroidal progenitor cell infiltration and angiogenic factor expression.