Temporal changes in the cell population and wound healing-related gene expression in deep partial-thickness burn wound model

Abstract

Abstract Background Burns are injuries that lie on the skin or other organic tissues caused by exposures to the heat, electricity, chemicals or ionizing radiation. The present study was carried out to record temporal changes in the cell population and wound healing-related gene expression in rats with deep partial-thickness burn. Methods Burn wound was induced on the dorsal part of Sprague-Dawley rats using temperature-regulated 20-mm wide aluminum head heating device. Animals were then sacrificed on days three, seven, 11, 14 and 21 post-burn, respectively. Half of the wounded skin tissues were dissected and fixed in buffered neutral formalin for Hematoxylin & Eosin (H&E) staining, and the other half were cut off and stored in − 20 °C for real-time PCR analyses. Results The number of adipose cells was found to be maximal on the 3rd day post-burn, and it gradually decreased over time and completely disappeared on day 11 post-burn. The maximum number of neutrophils were found to be on the 3rd and 14th day post-burn, while the maximum number of myofibroblasts were found on the 11th day post-burn. The number of lymphocytes did not change too much during the whole healing process. At the gene expression level, the expression pattern of inflammation-related genes including IL-6, TNF-α and iNOS were similar, which was found to be increased from day 3 to day 11 and decreased thereafter. Angiogenesis related genes including both VEGF-A and TGF-β1 showed a same expression pattern, both of which were slightly increased from day 3 to day 14 and smoothly decreased on day 21 post-burn. Matrix re-modeling related genes including MMP-2, TIMP-2 and Collagen-1 changed over time synchronously, where they all persistently increased from day 3 till day 14, then slightly declined on day 21 post-burn. Conclusion The present study revealed the changes in the cell population and expression profile of wound healing-related genes in deep partial-thickness burn, which could provide a cellular and genomic basis for the future research of burn injuries.