Abstract
Summary
We found an increased natural expression of the growth factors bFGF, BMP-12, VEGF, and TGF-b1 during tendon healing of rat Achilles tendons. External application of these growth factors improved the tendons failure load in the early healing phase.
Introduction
Tendon ruptures recover slowly and the healing of injuries can be devastating. Growth factors are known to influence tendon healing. However, only little is understood about growth factors in a healing tendon. Aim of this study was to investigate the influence of growth factors on tendon healing of rats following their natural expression.
Methods
The Achilles tendon of rats were transected and resutured. First the expression of bFGF, BMP-12, VEGF and TGF-b1 was assessed by immunohistochemical analysis 1 to 8 weeks after surgery. Second the maximal failure load of healed Achilles tendons was measured dependent on the external application of bFGF, TGF-b1 and BMP-12.
Results
The natural expression of bFGF (p<0.05), BMP-12 (p<0.05), TGF-b1, and VEGF was highest 1 week after transection. VEGF expression persisted during the remaining period whereas bFGF and BMP-12 declined. TGF-b1 expression peaked again after 8 weeks. A combined application of bFGF, TGF-b1 and BMP-12 resulted in a 4fold greater load to failure after 1 week (p<0.05), whereas a sequential treatment of these growth factors increased the load to failure even 5.5fold (p<0.05).
Conclusion
During natural tendon healing the growth factors bFGF, BMP-12, VEGF, and TGF-b1 are differentially expressed. Additional administration of the mentioned growth factors can improve the load to failure in the early healing phase of rat Achilles tendons.
