Active exercise promotes Achilles tendon healing and is accompanied by the upregulation of collapsin response mediator protein-2 in rats

Abstract

Collapsin response mediator protein-2 (CRMP-2) is involved in neurite elongation and regeneration; however, its role in wound healing remains to be elucidated. The present study aimed to investigate the effects of active mobilization treatment on Achilles tendon healing and to determine the role of CRMP‑2 in the healing process. Sprague Dawley rats were subjected to Achilles tendon injury, which was verified by hematoxylin and eosin staining and scanning electronic microscopy. Immobilization induced the disruption of collagen fibril arrangement and promoted collagen fibril damage. The average collagen fibril perimeter in the active mobilization group was significantly increased compared with in the immobilization group (125.6±0.8 nm vs. 119.9±1.7 nm; P<0.05). In addition, immunohistological analysis revealed that CRMP‑2 expression was significantly upregulated, particularly in the ruptured site of Achilles tendon tissues derived from animals in the mobilization group compared with the immobilization group (0.32±0.00 vs. 0.08±0.00; P<0.05). The increased CRMP‑2 levels were also confirmed by western blotting (active mobilization group, 0.71±0.03; immobilization group, 0.49±0.01 nm; P<0.05). These results indicated that active mobilization may promote Achilles tendon healing via upregulation of CRMP‑2 protein expression.

Muscle Contraction is Essential for Tendon Healing and Muscle Function Recovery after Achilles Tendon Rupture and Surgical Repair

“…Recent studies reported that shortening the immobilization period and active exercise increase collagen fiber diameter and promote tendon maturation, and long-term ankle immobilization causes gaps, uneven thickness, and fragmentation of collagen fibers, resulting in disorder. 16,[37][38][39] In these studies, removing immobilization orthosis could increase mechanical loading on tendons due to a combination of factors, including the amount of loading, ankle range of motion, and muscle activity. Then, applying mechanical stress to the healing AT in some way contributes to tendon healing.…”

Exploring the role of mechanical forces on tendon development using in vivo model: A scoping review

“…In addition, one study investigated the effects of thrombospondin2 ( Thbs2 ), an ECM protein that modulates collagen fibrillogenic and angiogenesis 46 on tendon mechanobiology. In connective tissue development, as assessed using Tnmd expression, 47 angiogenesis may potentially be involved in tissue maturation 48,49 . The tail tendon degenerated in TSP2 ‐null mice and provided an impression of increased laxity in the tail 50 .…”