FIG. 5.

Analysis of various kinematic parameters at a speed of 0.4m/sec 5 weeks post-fibroblast grafting with respect to pre-transection. Stance length, D_a (horizontal displacement of the foot relative to hip at toe-down), D_p (horizontal displacement of the foot relative to hip at liftoff), swing height, and hip height are normalized to pre-transection means (100%). (A) There was a significant effect of group on recovery of stance length (linear mixed model, p = 0.012), with the SUB-CHRONIC and CHRONIC groups recovering to significantly higher levels than the CONTROL group. Recovery in the ACUTE group was not significantly different from that in any other group, and was comparable with prior results with body-weight-supported locomotor training or xenografts indicated by the labeled lines. Recovery in stance length index obtained with body-weight-supported locomotor training is indicated by a dashed-dotted line,^1,32 whereas the recovery obtained with xenografts producing neurotrophins with no locomotor training is indicated by a dotted line.¹² (B) D_a 5 weeks after grafting was lower than pre-transection in all cats (95% confidence interval [CI] did not contain pre-transection mean); however, there was no significant difference among groups (linear mixed model, p = 0.444). There was a high variability in D_p among groups after grafting, as well as a significant effect of group (linear mixed model, p = 0.006). D_p in the SUB-CHRONIC group was significantly higher than in the CONTROL group. The graft groups trended to have a higher D_p than pre-transection, whereas the CONTROL group trended below pre-transection. For the ACUTE and CHRONIC groups, the pre-transection mean was within the 95% CI. (C) There was no significant effect of group on swing height (linear mixed model, p = 0.369). No group was significantly different from pre-transection. (D) There was no significant effect of group on hip height (linear mixed model, p = 0.247). The CHRONIC group, however, had a significantly higher hip height compared with pre-transection. (E) Step duration was unchanged for the ACUTE, SUB-CHRONIC, and CHRONIC groups after transection and grafting. (F) Similarly, there was no change in stance duration after transection and grafting. The limited number of high-quality post-transection steps precluded analysis of step and stance duration in control cats. Error bars indicate the standard error of the mean (SEM). *p < 0.05; **p < 0.01; †pre-transection group mean (100%) falls within the group's 95% CI post-injury.