The role of C5a and C5aR in pathological angiogenesis in ROP. (A) WT mice subjected to the ROP model were treated on day p12.5 with an i.p. injection of anti-C5 or an isotype control antibody. Data are mean ± SEM (n = 6-7 pups per group) and are shown as percentage of control. Number of epiretinal nuclei in control treated mice represents the 100% value. *P < .01. (B) WT mice were subjected to the ROP model and were treated from day p12-16 with daily intraperitoneal injections of C5a receptor antagonist (C5aR-ant.) or control antagonist. Data are mean ± SEM (n = 17-19 pups per group) and are shown as percentage of control. Number of epiretinal nuclei in control treated mice represents the 100% value. *P < .05. (C) WT mice subjected to the ROP model were treated from p12-16 with daily intraperitoneal injections of C5a or vehicle control. Data are mean ± SEM (n = 17 pups per group) and are shown as percentage of control. Number of epiretinal nuclei in control treated mice represents the 100% value. *P < .05.