Figure 2. Microglia ablation prevents subretinal neovascularization in Vldlr^–/– mice.

(A–C) Pharmacological microglia ablation using the CSF-1R inhibitor Ki 20227 in Vldlr^–/–; Cx3cr1^GFP/+ mice. (A) Subretinal neovascular (NV) tufts and GFP-positive microglia/macrophages were analyzed using GS-lectin staining in P17 Vldlr^–/–; Cx3cr1^GFP/+ mice treated with vehicle or Ki20227 from P10 to 16. Both (B) GFP-positive pixels and (C) the number of subretinal NV tufts were significantly reduced in Ki20227-treated mice retina. The P values were calculated using an unpaired 2-tailed t test (vehicle: n = 4, Ki20227: n = 6). (D and E) Genetic ablation of microglia in Vldlr^–/– mice was achieved by crossing Cx3cr1^Cre-ERT; Vldlr^–/– mice and Rosa26^iDTR/+mice. (D) The NV tufts in P23 Rosa26^iDTR/+; Vldlr^–/– and Cx3cr1 ^Cre-ERT; Rosa26^iDTR/+; Vldlr^–/– mice were analyzed by GS-lectin staining after 4-hydroxytamoxifen (4HT) treatment at P10 and P11, followed by P12-P14 diphtheria toxin (DT) treatment, demonstrating a marked reduction of NV tufts in Cx3cr1 ^Cre-ERT; Rosa26^iDTR/+; Vldlr^–/– mice (Rosa26^iDTR/+; Vldlr^–/–: n = 11, Cx3cr1 ^Cre-ERT; Rosa26^iDTR/+; Vldlr^–/–: n = 15) (E). Error bars indicate the mean ± SEM. The P values were calculated using an unpaired 2-tailed t test. ****P < 0.0001. Scale bars: 1 mm.