Microglia and Retinal Vascularity: A Deeper Dive into Branching Dynamics

PURPOSE This study explored the regulatory role of microglia in retinal vascular development, particularly their effects on vascular bifurcation and maturation. The study aimed to elucidate how microglia influence retinal vascular complexity and maturation.

METHODS Using CX3CR1GFP/+ reporter and pharmacological depletion mouse model, retinas were analyzed at P42 via immunofluorescence staining and confocal microscopy. Primary brain-derived microglia and brain microvascular endothelial cells were used for in vitro co-culture experiments. Quantitative assessments of vascular bifurcation points were performed via ImageJ software. Tangential frozen sections were used to analyze spatial relationships.

RESULTS The results revealed an increase in vascular bifurcation complexity, which was correlated with microglia density. Conversely, microglial depletion led to a significant reduction in vascular bifurcation, particularly in the peripheral retina, impairing the formation of the vascular network. In vitro, co-culture with microglia enhanced endothelial cell tube formation and sprouting.

CONCLUSION Our findings reveal a strong association between microglial distribution and vascular patterning, supporting the role of microglia in normal retinal vascular development and offering perspectives for future research.