Figure 4.

HIS, but not LIS, alleviates nociceptive behavior in CPIP mice, but there is no difference in serum corticosterone content among control and CPIP mice subjected to exercise or no exercise.

(A, B) HIS (A) and LIS (B) protocols. (C–F) Compared with the no exercise and LIS groups, bilateral mechanical and thermal pain thresholds were significantly increased in the HIS group in CPIP mice (n = 6 mice/group in the no exercise group; n = 6 mice/group in the LIS group; n = 6 control mice; n = 7 CPIP mice in the HIS group). **P < 0.01, vs. no exercise CPIP mice; #P < 0.05, ##P < 0.01 and ###P < 0.001, vs. LIS CPIP mice. (G–J) The distance traveled (G), velocity (H), time spent in the center of the open field test (I), and immobility time during the tail suspension test (J) did not differ among control and CPIP mice subjected to exercise or no exercise (n = 6 control mice and n = 5 CPIP mice with no exercise; n = 5 control mice and n = 7 CPIP mice with exercise (G–I); n = 7 mice/group (J)). (K) HIS does not affect serum corticosterone levels in control and CPIP mice 24 hours after exercise (n = 3 control mice and n = 6 CPIP mice). (L) The percentage of swimming time during the HIS protocol did not differ between control and CPIP mice (n = 5 mice/group). All data are presented as the mean ± SEM, and were analyzed by one-way analysis of variance followed by Bonferroni post hoc test (C–F), two-tailed unpaired Student’s t-test (G–K), or two-way analysis of variance followed by Bonferroni post hoc test (L). Detailed statistical information is shown in Additional Table 2 ^{(125.3KB, pdf)} and Additional file 1 ^{(136.8KB, pdf)} . Control: The ankles of mice were surrounded by a cut-O-ring; CPIP: mice were submitted to chronic postischemia pain; HIS or Exercised: control or CPIP mice were performed high-intensity swimming; LIS: control or CPIP mice were performed low-intensity swimming; Non-exercised: control or CPIP mice were not performed swimming.