Fig. 2.

SNI produced gait alterations, but did not influence locomotion, social interaction, or anxiety-like behavior. (A) Spared nerve injury (SNI) caused a significant reduction in hindpaw mechanical withdrawal thresholds compared to sham operation on postoperative days (POD) 7–40 (n = 10–17/group). (B) SNI and sham mice exhibited equivalent wheel running activity at each testing timepoint between POD 5 and POD 41 (n = 12–18/group). Representative heatmaps from the social interaction test of (C) sham and (D) SNI mice in the absence (top) and presence (bottom) of an unfamiliar conspecific. Presence within circles reflects time spent atop the pencil cups. Scale bar indicates total time spent in each arena location. (E) Social interaction scores were equivalent between sham and SNI mice on POD 8/14 (n = 15/group). (F, G) Catwalk gait analysis demonstrated a significant reduction in ipsilateral hindpaw pressure, but no change in contralateral hindpaw pressure of SNI mice relative to sham mice on POD 11 through POD 39 (n = 10–23/group). (H) SNI significantly decreased hindpaw contact area compared to sham surgery. (I) Catwalk run speed did not differ between SNI and sham mice. (J, K) SNI mice had a significantly shorter stance phase and significantly longer swing phase relative to sham mice on POD 11 through POD 39. (L) SNI mice were impaired in the rotarod test, and had a significantly shorter latency to fall compared to sham mice across all trials on POD 8 (n = 10–12/group). (M, N) SNI did not affect distance moved or time spent moving in the open field test on POD 14–17 (n = 12–16). (O) SNI mice did not exhibit anxiety-like behavior in the open field test compared to sham mice on POD 14–17. Data are presented as mean ± SEM. Student’s t-Test, Holm-Sidak correction for multiple comparisons, when appropriate. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001, as compared with sham mice.