Muscle repair after a transsection injury with development of a gap: an experimental study in rats.

Lacerated muscle needs fusion with muscle fibres to regain good function, but it often lose its elasticity and the repair seems poor. We think that the scar healing is caused by the development of a gap. In this study in 20 rats we made silicone tube models to keep a constant distance between the muscle ends, and examined the repair inside the silicone tube. In the short gap (1 mm), aligned collagen fibres and muscle fibres bridged both ends. However, when the gap was long (4 mm) they could not bridge both ends and collagen fibres covered the cut ends of muscle. Muscle contains a large fibrous component and will regenerate simultaneously after transsection injury. This result suggests that fibrous repair influences the muscle repair and muscle regeneration will be disturbed as the gap widens.