T-cells in vitro proliferation shows no change in the mice with chronic spinal cord injury (SCI). Isolated splenocytes (2 × 105) from uninjured (CT) or T9-SCI mice at chronic phase after injury (SCI) were labeled with CFSE and stimulated ex vivo for three days with anti-CD3+CD28+IL-2 or with IL-2 only. (A) Representative histogram plots show the CFSE fluorescence of CD4+ T-cells and CD8+ T-cells following three-day stimulation with anti-CD3+CD28+IL-2 or with IL-2 only. (B) The line graph shows the percentage of CD4+ T-cells and CD8+ T-cells that have undergone zero to five divisions. Twenty thousand events gated on CD4+ T-cells or CD8+ T-cells were collected. n = 5 mice per group. No statistical difference was detected between the two groups. P > 0.05, two-tailed Student’s t-tests were performed for each cell division number.