Investigation of the effects of umbilical cord-derived mesenchymal stem cells and curcumin on Achilles tendon healing - can they act synergistically?

BACKGROUND: It is known that curcumin and umbilical cord-derived mesenchymal stem cells (UC-MSCs) positively affect experimental tendon injury healing. This study investigated individual effects and potential synergistic effects of using curcumin and UC-MSCs alone and together.METHODS: Eighty female Wistar albino rats were randomly divided into five groups: Control, curcumin, sesame oil, MSCs, and Curcumin+MSCs groups. In all rats, punch tendon defect was created in both right and left Achilles tendons. While no additional treatment was applied to the control group, curcumin, sesame oil used as a solvent for curcumin, MSCs, and MSCs and curcumin com-bination were applied locally to the injury site, respectively, in the other groups. Curcumin was solved in sesame oil before application. In each group, half of the animals were euthanized in the post-operative 2nd week while the other half were euthanized in the post-operative 4th week. The right Achilles was used for biomechanical testing, while the left Achilles was used for histological evaluation and immunohistochemical analysis of type I, Type III collagen, and tenomodulin.RESULTS: Histologically, significant improvement was observed in the curcumin, MSCs, and Curcumin+ MSCs groups compared to the control Group in the 2nd week. In the 2nd and 4th weeks, Type III collagen was significantly increased in the curcumin group com-pared to the control group. In week 4, tenomodulin increased significantly in the curcumin and MSCs groups compared to the control group. Tendon tensile strength increased significantly in MSCs and Curcumin+MSCs groups compared to the control group in the 4th week. No superiority was observed between the treatment groups regarding their positive effects on recovery.CONCLUSION: Locally used curcumin and UC-MSCs showed positive effects that were not superior to each other in the healing of injury caused by a punch in the Achilles tendons of rats. However, synergistic effects on healing were not observed when they were applied together.