Fig. 2
From: Neuregulin-1 elicits a regulatory immune response following traumatic spinal cord injury
Nrg-1 promotes Treg cell response in the injured spinal cord. a, b Representative images of the gating strategy for flow cytometry after singlet selection are provided for vehicle- and Nrg-1-treated groups. c At 3-day post-injury, the number of CD3+CD4+ T cells in the spinal cord was significantly higher in vehicle-treated animals compared to uninjured control group. There was no significant difference in the population of infiltrated helper T cells and the number of FoxP3+ Treg cells (CD3+CD4+FoxP3+) between vehicle- and Nrg-1-treated groups. However, the population of IL-10 producing CD4+ T cells (CD3+CD4+IL-10+) was significantly increased in Nrg-1-treated animals in comparison to vehicle-treated group. d At 7 days post-SCI, despite no significant difference in the total helper and regulatory T cell populations between vehicle- and Nrg-1-treated groups, a significant reduction (1.9-fold) was observed in IFNγ producing effector T cell population in Nrg-1-treated SCI rats compared to their vehicle-treated counterparts. e At 14 days post-SCI, infiltrated helper T cells reached their lowest level among all examined time-points, and Nrg-1 treatment had no significant effect on the total helper T cell population. IL-10 expressing Treg cells were significantly higher in both vehicle and Nrg-1 injured rats compared to uninjured animals. Nrg-1-treated animals showed a significantly higher number of Treg cells in their spinal cord at 14-day time-point compared to vehicle-treated rats. f However, at chronic (42-day) time-point, the number of T helper cells reached a maximum, with Nrg-1-treated animals harboring a significantly decreased population of CD4+ T-cells in their spinal cord compared to the vehicle-treated group. Most importantly, CD3+CD4+FoxP3+ and CD3+CD4+IL-10+ regulatory T cell populations were significantly increased in Nrg-1-treated groups. g Immunohistochemical images show the presence of Treg cells in the perilesional area (N = 5/group/time-point, *p < 0.05, **p < 0.01, ***p < 0.001, one-way ANOVA followed by Holm-Sidak post hoc test)