Fig 1: Preferential microglia proliferation and infiltrating macrophage apoptosis in the lesioned CNS.(A and C) Representative immunohistochemical images of the lesioned spinal cord (A) and sciatic nerve (C) demonstrating more proliferative (Ki67+, green) reporter-positive cells (yellow, arrowheads) compared to reporter-negative cells (white, boxes) in the CNS and no difference between cell types in the PNS. This observation was also reflected in quantification (*P < 0.02) (B and D). (E and F) Representative immunohistochemical images of the lesioned spinal cord (E) and sciatic nerve (F) at 3 days after LPC demonstrating more apoptotic (CC3+ green) infiltrating macrophage (CD45+ tdTom-, yellow, arrowheads) in the CNS versus the PNS. This observation was also reflected in quantification (*P < 0.03; G and H). (I to K) Using conditioned media (CM) from spinal cord (CNS) and sciatic nerve (PNS) on BMDM, we demonstrated a reduction in cell numbers (J) and an increase in apoptosis (CC3+ cells; K) in CNS-primed media conditions compared to PNS-primed media. n = 6 to 7, *P < 0.02. (B), n = 3 to 4 (D); two-way ANOVA with Sidak’s multiple comparison test; n = 4 (PNS) and 9 (CNS) two-way ANOVA with Sidak’s multiple comparison test (G and H); n = 6 (two independent experiments) ANOVA with Tukey’s multiple comparison test (I to K); Error bars indicate ± SEM. Scale bar, 20 µm. FOV, field of view.