Region-Specific Effects of Weight-Bearing and Non-Weight-Bearing Exercise on Schwann Cell Transcription Factors and Functional Recovery Following Sciatic Nerve Injury

This study aimed to investigate the region-specific effects of weight-bearing and non-weight-bearing exercise on Schwann cell transcriptional activity and functional recovery following sciatic nerve injury. Five-week-old male Sprague-Dawley rats were randomly assigned to four groups: normal control (CONT), sedentary after injury (SED), treadmill exercise (TEX), and swimming exercise (SWIM). All groups except CONT underwent sciatic nerve crush injury, with TEX and SWIM groups receiving daily exercise interventions and SED remaining inactive. Sox10 and Krox20 expression levels were analyzed in proximal, injury, and distal (P-I-D) nerve segments at 3 and 21 days post-crush using qualitative and quantitative Western blot analysis. Functional recovery was evaluated using forelimb grip strength and the sciatic functional index (SFI). At 3 days post-crush, Sox10 expression in the distal segment was significantly higher in TEX and SWIM groups compared to SED, with TEX exceeding SWIM. At 21 days, Sox10 expression remained elevated in TEX compared to both SED and SWIM. Krox20 expression followed a similar pattern at 3 days, with higher levels in TEX and SWIM than SED, and TEX again showing greater expression than SWIM; however, these differences disappeared by day 21. Functionally, the TEX group demonstrated significantly greater grip strength and improved SFI at 21 days post-injury. The CONT group maintained baseline values throughout the experiment. These findings suggest that early moderate-intensity treadmill exercise enhances Schwann cell-mediated nerve regeneration through region-specific transcriptional activation and supports more effective functional recovery than non-weight-bearing exercise.