Conversion of stromal vascular fraction in the microenvironment of radiation-induced skin injuries and its clinical implications / 中华放射医学与防护杂志

ABSTRACT

Objective:To investigate the conversion of stromal vascular fraction (SVF) in the microenvironment of radiation-induced skin injuries to provide guidance for clinical applications.Methods:Based on a random number table, C57BL/6N mice were categorized into four groups: the blank control, negative control, acute injury, and chronic injury groups, with each group containing 25 mice. The backs of mice in the blank control, acute injury, and chronic injury groups were exposed to 15 Gy X-ray irradiation. Then, the mice in the negative control, acute injury, and chronic injury groups were injected subcutaneously with the SVF derived from B6/G-R mice. The survival of these mice was observed 1, 3, 7, 14, and 21 d after the injection through fluorescence tracing and in vivo imaging. Accordingly, the clinical SVF injection regimens were optimized based on the experimental result of mice. Finally, local SVF injection was performed on different frequencies for patients in different wound conditions, with the efficacy being observed. Results:The fluorescence of SVF was observed from the tissue slices of the acute injury, chronic injury, and negative control groups 14 d post-injection. The result showed that the fluorescence intensity of SVF 1, 3, and 7 d post-injection was in the order of the negative control group > the acute injury group > the chronic injury group. The acute injury group ranked at the top and the chronic injury group remained at the bottom 14 d after the injection. The fluorescence of SVF in each group was barely detected 21 d after the injection. Compared to the negative control group, the acute injury group exhibited statistical differences only 14 d post-injection ( t = 4.11, P < 0.05), while the chronic injury group displayed statistical differences 1, 3, 7, and 14 d after the injection ( t = 3.88-5.74, P < 0.05). Furthermore, the acute injury group exhibited significantly higher fluorescence intensity of SVF than the chronic injury group ( t = 4.73-8.38, P < 0.05). The half-life of SVF for the negative control, acute injury, and chronic injury groups was 6.336, 6.014, and 2.163 d, respectively. As indicated by the application of SVF transplantation based on traditional surgical protocols in the clinical trial, SVF can significantly promote wound repair, with earlier SVF transplantation being more beneficial for wound healing. Conclusions:The conversion of SVF differs in the microenvironments of acute and chronic radiation-induced skin injuries. This can serve as an essential guide for the administration timing and injection frequency of SVF in clinical applications.