Thymosin β4 enhances the healing of medial collateral ligament injury in rat
Introduction
Injury to the medial collateral ligament (MCL) is the most common knee ligament injury and frequently occurs in various types of athletic accidents [1]. MCL has been the most-used model for ligament and tendon healing studies because of its accessibility, frequency of injury, and healing properties [2]. Ligament is composed of a few cells and parallel arrays of collagen fibers. Although MCL can heal without surgical intervention, its regeneration is very difficult and requires a very long period. Moreover, the return at the initial state of the histological, biochemical and biomechanical properties in the healing tissue is never reached [3]. The restoration of mechanical strength is one of the goals of ligament healing. A method to accelerate the healing of this ligament could lead to reductions in recovery time, and increased patient compliance with a shorter rehabilitation requirement. Although recent in vivo studies have reported that growth factors, biological scaffold, and stem cell therapies enhance healing in the injured MCL [4], [5], [6], but the best protocol to improve ligament healing has not yet been established.
Recently, thymosin β4 (Tβ4) showed premise in being an efficacious treatment for tissue injuries in dermis and heart by its physiological functions, such as wound healing, angiogenesis, and cell migration [7], [8], [9]. Tβ4 is a highly conserved water-soluble peptide. It has multiple biological activities that contribute to reduce tissue damage and to promote tissue repair [10]. Tβ4 treatment could result in stem cell activation, mediate oligodendrocyte differentiation during the process of brain injury, and thus promote functional recovery [11], [12]. It could also regulate angiogenesis by mobilizing and recruiting progenitor cells during the repair damaged myocardium [13]. A recent paper reported that the expression level of Tβ4 was high in muscle injury site, where it serves as a chemoattractant for myoblasts. This result indicated that Tβ4 has an ability to facilitate skeletal muscle regeneration [14]. The administration of Tβ4 into rat skin excision wounds improved the organization of collagen fibers in the absence of myofibroblast, and incisional wounds in the Tβ4-treated group healed with minimal scaring and without loss in wound breaking strength [10], [15]. Moreover, Tβ4 elevates granulation tissue deposition, induces angiogenesis, and enhances collagen deposition in wound repair [7], [16]. However, the use of Tβ4 in improving the healing of MCL injury has not been reported previously.
Based on these facts, we hypothesized that the addition of Tβ4 would induce collagen fiber bundles to be better organized in healing ligament, which would form a basis for increased mechanical property. The fibrin sealant was considered to act as a useful vehicle releasing Tβ4 in the in vivo conditions. The purpose of this experimental study was to evaluate the in vivo effect of the local application of Tβ4 in fibrin sealant on the healing MCL in rat knee joint using histological studies and mechanical testing.
Section snippets
Surgical procedure
60 adult, male, Sprague-Dawley rats weighing between 180 and 200 g were used in this study. Animal experiments were carried out under the Rules and Regulations of the Animal Care and Use Committee at Harbin Medical University. On the day of surgery, the rats were anesthetized with xylazine and ketamine. With a sterile technique, a 1.5-cm skin incision was made over the medial aspect of the right knee, and the MCL was exposed. The ligament was then sharply transected together with the fascia
Results
No adverse effect of Tβ4 on the rats' overall well-being was apparent in either group. There were no significant differences among 3 groups with regard to the average weight of the animals during the experimental period. One day after surgery, all rats resumed normal cage activity.
Discussion
MCL injuries account for a significant percentage of knee ligament injury and enormous associated costs. The number of MCL injuries will continue to increase as our population continues to age and remain active. Methods of treating ligament injuries have seen substantial improvements. However, formation of the fibrotic scar tissue and decreased function are still common problems. Therefore, a new strategy needs to be developed to optimize the remodeling of MCL injury.
Previous studies found that
Acknowledgments
This work was supported by grants from the National Natural Sciences Foundation of China (no.30901516, 81272049, 81150024), Reserve Talents of Universities Overseas Research Program of Heilongjiang, and Natural Science Foundation of Heilongjiang (QC2011C049).
References (26)
- et al.
Biomechanics of knee ligaments: injury, healing, and repair
J Biomech
(2006) - et al.
Promotion of rabbit ligament healing by local delivery of hepatocyte growth factor
J Orthop Sci
(2011) - et al.
Ligament regeneration using a knitted silk scaffold combined with collagen matrix
Biomaterials
(2008) - et al.
Thymosin beta4 promotes the migration of endothelial cells without intracellular Ca2 + elevation
Exp Cell Res
(2012) - et al.
Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues
Trends Mol Med
(2005) - et al.
Thymosin beta4 improves functional neurological outcome in a rat model of embolic stroke
Neuroscience
(2010) - et al.
Controlled release of thymosin beta4 using collagen–chitosan composite hydrogels promotes epicardial cell migration and angiogenesis
J Control Release
(2011) - et al.
MCL injuries of the knee: current concepts review
Iowa Orthop J
(2006) - et al.
Healing and repair of ligament injuries in the knee
J Am Acad Orthop Surg
(2000) - et al.
Role of angiogenesis after muscle derived stem cell transplantation in injured medial collateral ligament
J Orthop Res
(2012)
The regenerative peptide thymosin beta4 accelerates the rate of dermal healing in preclinical animal models and in patients
Ann N Y Acad Sci
Thymosin beta 4 is dispensable for murine cardiac development and function
Circ Res
Thymosin beta 4 mediates oligodendrocyte differentiation by upregulating p38 MAPK
Glia
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Bo Xu and Mowen Yang are first authors equally.