PCI34051 and VPA have no effect on CD4+, MHCII+, and Arg-1+ cell numbers after SCI. Spinal cord sections were labelled for CD4+ cells (T helper cells, A), MHCII+ cells (classically activated macrophages/microglia, B), and Arg-1+ cells (alternatively activated macrophages/microglia, C). (A) The number of CD4+ cells was counted in complete spinal cord sections. (B–D) MHCII+, Arg-1+, and MHCII+/Arg-1+ cells were counted at the lesion area. Data are represented as means ± SEM, n = 3–4 mice/group. ** p < 0.01. Arg-1: arginase-1; CD4: cluster of differentiation 4; MHCII: major histocompatibility complex 2; PCI: PCI-34051; SCI: spinal cord injury; VPA: valproic acid.