Thymosin β4 enhances the healing of medial collateral ligament injury in rat

The role played by thymosin beta 4 (T beta 4) in the process of wound healing was reported in several organs. However, there have been no reports that investigated the role of T beta 4 in the repair process after ligament injury. The purpose of this study was to determine whether administration of T beta 4 would improve ligament repair following injury. The medial collateral ligament (MCL) was sharply transected on the day of surgery. Then, the treatment group received 100 mu L. of fibrin sealant containing 1 mu g of T beta 4 placed in the ligament gap. Healing tissues were evaluated by hematoxylin and eosin stain, transmission electron microscopy, and biomechanical test at 4 weeks after surgery. Histologically, healing tissues in T beta 4-treated group exhibited uniform and evenly spaced fiber bundles. However, the collagen fibers were not evenly spaced in control rats. Moreover, diameters of collagen fibrils within granulation tissue from the T beta 4-treated rats were significantly increased. In T beta 4-treated MCLs, the mechanical properties of these healing tissues were significantly higher at 4 weeks after surgery. In terms of the mechanical properties of the healing femur-medial collateral ligament-tibia complexes, the T beta 4-treated group had significantly better biomechanical properties than the control group at 4 weeks after surgery. Local administration of T beta 4 promotes the healing process of MCL, both histologically and mechanically, in a rat model. These findings provide a basis for potential clinical use of T beta 4 in repairing ligaments. (C) 2013 Elsevier B.V. All rights reserved.