Whole-mount CD31 immunostaining. The white line defines the whole retinal area, and red line outlines the vaso-obliterative zone. Inset image shows large numbers of peri-retinal tufts (i, arrow heads) in control IgG-Fc-treated retinae compared to Sema3C-treated retinae (ii). Scale bar, 500 μm (upper panel) and 100 μm (lower panel).The avascular area is presented as percentage of the whole retinal area (n = 10 retinae in each group; n.s., non-significant using paired Student's t-test).The formation of pre-retinal tufts was quantified in the superficial layer of the retinal vasculature and normalized to whole retinal area (n = 6 retinae in each group; *P = 0.033 using paired Student's t-test). 