Systemic Lipopolysaccharide Exposure Exacerbates Choroidal Neovascularization in Mice

This study aims to investigate the effect of a systemic lipopolysaccharide (LPS) stimulus in the course of laser-induced choroidal neovascularization (CNV) in C57BL/6 J mice. A group of CNV-subjected mice received 1 mg/kg LPS via the tail vein immediately after CNV induction. Mouse eyes were monitored <i>in vivo</i> with fluorescein angiography for 2 weeks. <i>In situ</i> hybridization and flow cytometry were performed in the retina at different time points. LPS led to increased fluorescein leakage 3 days after CNV, correlated with a large influx of monocyte-derived macrophages and increase of pro-inflammatory microglia/macrophages in the retina. Additionally, LPS enhanced <i>Vegfα</i> mRNA expression by <i>Glul</i>-expressing cells but not <i>Aif1</i> positive microglia/macrophages in the laser lesion. These findings suggest that systemic LPS exposure has transient detrimental effects in the course of CNV through activation of microglia/macrophages to a pro-inflammatory phenotype and supports the important role of these cells in the CNV course.