目的：探讨术后康复训练起始时机对脊髓损伤大鼠步态恢复的影响，为脊髓损伤后康复训练时间点 的设置提供实验依据。方法：将16只SD大鼠随机分为正常组、脊髓单损组（仅给予脊髓损伤）、3天康复组 （损伤后3天开始康复训练）、7天康复组（损伤后7天开始康复训练），各4只。在建立脊髓中度挫伤大鼠模 型后，对训练组分别于造模后第3天和第7天开始，每天以双足行走的方式进行40 min的跑台康复训练，并 于损伤后2周通过高速摄像系统采集大鼠下肢的步态数据。采用主成分分析（PCA）挖掘行走过程中的关键 步态特征及行为指标并进行组间比较，评估不同训练时机对大鼠下肢运动能力恢复的影响。结果：PCA分 析表明，在主成分空间中，7天康复组与正常组最接近，明显优于3天康复组和单损组（均P＜0.0001）。在 PC1得分方面，7天康复组的表现显著优于3天康复组和脊髓单损组（均P＜0.0001）；3天康复组也优于脊髓 单损组（P=0.0127）。在 PC2 得分方面，7 天康复组与正常组之间的差异（P＜0.05）小于 3 天康复组（P＜ 0.0001）和脊髓单损组（P＜0.001）。在关键步态参数中，7 天康复组的肢体末端轨迹 MTP 向前位移为 （6.610±1.030）mm，显著高于3天康复组（1.425±1.167）mm和脊髓单损组（1.473±1.270）mm，均P＜0.0001； MTP最大速度为（5.317±1.380）mm/s，也最接近正常状态（7.517±1.404）mm/s。7天康复组踝关节向前运动 量为（2.651±0.921）mm，显著优于 3 天康复组（0.752±0.807）mm 和脊髓单损组（0.572±0.352）mm，均 P＜ 0.0001。此外，在稳定性和速度等指标中，3天康复组在站立时间（2.155±1.493）s及膝关节垂直振荡等方面 与正常组（0.647±0.376）s具有最大差异（P＜0.0001）。结论：与3天康复组相比，7天康复组的大鼠在步态各 项指标上更接近正常组，表现出更好的下肢功能恢复效果。

This study examines the effects of postoperative rehabilitation timing on gait recovery in rats with spinal cord injuries (SCI). The findings aim to provide evidence for determining the optimal time for commencing rehabilitation after SCI. Methods: Sixteen Sprague-Dawley (SD) rats were randomly allocated into four groups: the normal group (N group), injury-only group (S group), rehabilitation starting 3 days post-injury group (3 d group), and rehabilitation starting 7 days post-injury group (7 d group). After inducing a moderate spinal cord contusion in the rats, the 3 d and 7 d groups underwent 40 minutes of treadmill rehabilitation, focusing on bipedal walking, on the respective days post-injury. Gait data from the rat’s hindlimbs were captured using a high-speed camera system two weeks post-SCI. Principal component analysis (PCA) was employed to identify key gait features and behavioral indicators during walking, which were then compared across groups to assess the influence of varied training initiation times on the restoration of lower limb motor function in rats. Results: PCA indicated that, within the principal component space, the 7 d group was most similar to the normal group. This was significantly better than the 3 d group and the S group (both P<0.0001). For the PC1 score, the 7 d group outperformed both the 3 d group and the S group (both P<0.0001), while the 3 d group also surpassed the S group (P=0.0127). Regarding the PC2 score, the discrepancy between the 7 d group and the N group (P<0.05) was less pronounced than for the 3 d group (P<0.0001) and the S group (P<0.001). In key gait parameters, the forward displacement of the metatarsophalangeal (MTP) in the 7 d group was (6.610± 1.030) mm, markedly higher than in both the 3 d group (1.425±1.167) mm and the S group (1.473±1.270) mm (both P<0.0001). The peak speed of MTP in the 7 d group was (5.317 ± 1.380) mm/s, closely mirroring the healthy state (7.517±1.404) mm/s. For ankle joint forward movement, the 7 d group recorded (2.651±0.921) mm, significantly superior to the 3 d group (0.752±0.807) mm and the S group (0.572±0.352) mm (both P<0.0001). Moreover, in terms of stability and speed metrics, the 3 d group displayed the most substantial deviation from the normal, with values of (0.647±0.376) s for standing time and (2.155±1.493) s for vertical knee joint oscillation (P<0.0001). Conclusion：Rats in the 7 d group exhibited gait metrics more akin to the normal state compared to the 3d group, suggesting a superior hindlimb functional recovery.