Umbilical Cord Stem Cells for Skin Grafts in Donor Site Wounds

The goal of this clinical trial is to evaluate the safety and effectiveness of human umbilical cord mesenchymal stem cell (hUCMSC) therapy in patients undergoing medium-thickness skin grafts for donor site wounds. The study aims to answer the following main questions: * Question 1: Does hUCMSC therapy improve the healing quality and speed of donor site wounds in comparison to standard treatment? * Question 2: Does hUCMSC therapy reduce scar formation in the donor site wounds? Participants in this study will undergo medium-thickness skin grafts, and those in the treatment group will receive hUCMSC therapy. The main tasks for participants will involve regular follow-up visits, monitoring of wound healing progress, and assessment of any potential side effects or complications associated with the therapy. In order to evaluate the effectiveness of hUCMSC therapy, researchers will compare the treatment group receiving hUCMSC therapy with a control group that receives standard treatment alone. The aim is to determine if the use of hUCMSC therapy leads to improved healing outcomes and reduced scar formation compared to the standard treatment group.