ABSTRACT
Tendon lesions are among the most frequent musculoskeletal pathologies. Vascular endothelial growth factor (VEGF) is known to regulate angiogenesis. VEGF-111, a biologically active and proteolysis-resistant splice variant of this family, was recently identified. This study aimed at evaluating whether VEGF-111 could have a therapeutic interest in tendon pathologies. Surgical section of one Achilles tendon of rats was performed before a local injection of either saline or VEGF-111. After 5, 15 and 30 days, the Achilles tendons of 10 rats of both groups were sampled and submitted to a biomechanical tensile test. The force necessary to induce tendon rupture was greater for tendons of the VEGF-111 group (p<0.05) while the section areas of the tendons were similar. The mechanical stress was similar at 5 and 15 days in the both groups but was improved for the VEGF-111 group at day 30 (p <0.001). No difference was observed in the mRNA expression of collagen III, tenomodulin and MMP-9. In conclusion, we observed that a local injection of VEGF-111 improves the early phases of the healing process of rat tendons after a surgical section. Further confirmatory experimentations are needed to consolidate our results.
ABSTRACT
Platelet-rich plasma (PRP) contains growth factors involved in the tissular healing process. The aim of the study was to determine if an injection of PRP could improve the healing of sectioned Achilles tendons of rats. After surgery, rats received an injection of PRP (n = 60) or a physiological solution (n = 60) in situ. After 5, 15, and 30 days, 20 rats of both groups were euthanized and 15 collected tendons were submitted to a biomechanical test using cryo-jaws before performing transcriptomic analyses. Histological and biochemical analyses were performed on the five remaining tendons in each group. Tendons in the PRP group were more resistant to rupture at 15 and 30 days. The mechanical stress was significantly increased in tendons of the PRP group at day 30. Histological analysis showed a precocious deposition of fibrillar collagen at day 5 confirmed by a biochemical measurement. The expression of tenomodulin was significantly higher at day 5. The messenger RNA levels of type III collagen, matrix metalloproteinases 2, 3, and 9, were similar in the two groups at all time points, whereas type I collagen was significantly increased at day 30 in the PRP group. In conclusion, an injection of PRP in sectioned rat Achilles tendon influences the early phase of tendon healing and results in an ultimately stronger mechanical resistance.
