Figure 1.

(A) Effects of human mesenchymal stem cells on reflex withdrawal responses (g, mean ± SEM) to mechanical noxious stimuli in SNI mice. The onset of SNI-induced mechanical allodynia was evaluated in ipsilateral sides every 10 days starting from day 11 until 90 days after surgery. Mice showed a significant reduction in the threshold to mechanical stimulation in the ipsilateral paw (*p < 0.05 vs. sham-operated mice) after SNI surgery. Human MSC treatment (on day 4 after SNI surgery, as indicated by the arrow) prevented the appearance of mechanical allodynia at 11, 20, 30, 40, 50, 60, 70, 80, and 90 days post-SNI (°p < 0.05 vs. SNI mice). (B) Effects of human mesenchymal stem cells on reflex withdrawal responses (s, mean ± SEM) to thermal noxious stimuli in SNI mice. The onset of SNI-induced thermal hyperalgesia was evaluated in ipsilateral sides every 10 days starting from day 11 until 90 days after surgery. SNI mice showed a significant reduction in withdrawal latency to radiant heat in the ipsilateral paw (*p < 0.05 vs. sham-operated mice). Human MSC treatment (on day 4 after SNI surgery, as indicated by the arrow) prevented the appearance of thermal hyperalgesia 11, 20, 30, 40, 50, 60, 70, 80, and 90 days post-SNI (°p < 0.05 vs. SNI mice). (C) Rotarod motor testing results. The effects of human mesenchymal stem cell injection on motor performance in the Rotarod test is shown. Systemic administration of hMSCs in tail vein of SNI mice had no effect on motor function compared with vehicle treated SNI mice. Human MSCs were injected on day 4 after the SNI surgery. Results are expressed as the mean ± SEM of the latency (s; n = 5 mice/group). *p < 0.05 vs. sham/vehicle.