Therapeutic Effect of Wharton's Jelly-Derived Mesenchymal Stem Cells and Conditioned Medium in a Carbon Dioxide Laser Burn Model: An Experimental Study.

Abstract

Introduction: Current burn animal models have disadvantages, such as standardization issues. Many mesenchymal stem cell studies have been conducted on burn treatments; however, the efficacy of Wharton's jelly mesenchymal stem cells (WJ-MSCs) and the conditioned medium (CM) on partial- and full-thickness burns remains unclear. Therefore, we aimed to investigate the healing potential of WJ-MSCs and CM in treating partial- and full-thickness skin burns using a new carbon dioxide (CO2) laser model.

Materials and methods: Sixty-two male Wistar rats (200-250 g) were used, with 56 rats divided into 4 groups based on treatment after laser application. Furthermore, to create varying degrees of skin burns, a fractional CO 2 laser (10.2 mJ, 10,600 nm) was applied to 6 rats for 15-120 s. A 60-s and 120-s laser application was performed on the back of each animal to create partial-thickness and full-thickness burns, respectively. WJ-MSCs, CM, and minimal essential media (MEM) were applied to partial- and full-thickness skin burns determined in a pilot study 24 h later. However, no treatment was administered to the SHAM group. Treatment efficacy was evaluated semi-quantitatively through macroscopic, histopathological, and immunohistochemical analyses and quantitatively through real-time quantitative reverse transcription polymerase chain reaction on days 7 and 14.

Results: Macroscopic and histopathological analyses (epidermal thickness, dermal thickness, number of skin appendages, and collagen scoring) showed significant improvements in the CM, WJ-MSCs, and MEM groups compared with the controls. Immunohistochemical staining indicated increased levels of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) in the treated groups compared with those in the SHAM group. quantitative reverse transcription polymerase chain reaction revealed the upregulation of VEGF, VEGF receptor 1, FGF, and FGF receptor 1 in the CM and WJ-MSCs groups compared with that in the SHAM and MEM groups, highlighting their roles in angiogenesis and re-epithelialization.

Conclusions: This study highlights the potential of WJ-MSCs and CM to enhance wound healing in CO 2 laser-induced partial and full-thickness skin burns. Additionally, a new noncontact CO 2 laser burn model that creates burns at varying degrees and is easy to standardize was developed.