Effects of L-carnitine on healing of Achilles tendon in rats

OBJECTIVES: In this experimental study, we aimed to analyze the effects of levocarnitine (L-carnitine) on tendon healing after surgical repair of Achilles tendon rupture in a rat model. MATERIALS AND METHODS: The study included 40 Wistar Albino rats divided into four groups: Group 1, neither surgical intervention nor substance applications were performed for the Achilles tendons. In the other groups, the right Achilles tendons were cut using a scalpel and repaired with a modified Kessler-type technique with 3/0 monofilament polydioxanone suture. In Group 2, the rats did not receive any additional treatment, except for surgical repair. In Group 3, the same volume similar to Group 4 of saline solution was administered intraperitoneally for seven days. In Group 4, each rat received 300 mg/kg of L-carnitine intraperitoneally for seven days. At Week 6, all rats were sacrificed. All right Achilles tendons were used for biomechanical tests and histopathological evaluations. Biochemical analysis of the matrix metalloproteinase was also performed using the blood specimens. RESULTS: There were no significant differences among the groups in terms of the histopathological parameters. Although the mean matrix metalloproteinase level was low in the L-carnitine group, it did not reach statistical significance. A significant increase in maximum force, tensile strength, and strength to 2-mm gap was observed in the L-carnitine group. CONCLUSION: The significant effects of L-carnitine on biomechanical parameters may indicate favorable effects on Achilles tendon healing in rats by reducing matrix metalloproteinase 2 and 9. To improve Achilles tendon healing, further investigation for these markers is needed. Since the effects of L-carnitine on the Achilles tendon cannot be clearly distinguished histopathologically, further studies involving L-carnitine-induced effects are warranted.