Analysis of mechanical sensitivity recovery. (A) Time for recovery of sensitivity to a mechanical stimulus using von Frey filaments. The withdrawal threshold (T50) is shown before and after left sciatic nerve crush injury. Vertical arrows indicate electro-acupuncture (EA) application, every two days for 15 min from 3 to 11 DPO (group 1). n is the number of mice in each group; values of T50 for the two groups were pooled before crush injury (n = 26). (DPO: day post operation). (B) (a) Effects of electro-acupuncture applied at the moment of pain development from 19 to 27 DPO (group 2). In (b) enlarged view of the period of pain-related symptoms shown in (a). * p < 0.05, *** p < 0.001 (ANOVA).