# The Model of an Ischemic Non-Healing Wound: Regeneration after Transplantation of a Living Skin

## TL;DR

This study tests a new model for non-healing wounds to evaluate how tissue-engineered skin helps regeneration in preclinical trials.

## Contribution

A novel ischemic non-healing wound model and a smoothing coefficient to assess tissue regeneration are introduced for preclinical biomedical product testing.

## Key findings

- Histology and immunohistochemistry are effective for evaluating wound treatment effectiveness.
- LSE transplantation promotes tissue formation and reduces mechanical stress in wound beds.
- The proposed smoothing coefficient indicates granulation tissue growth and wound healing progress.

## Abstract

The aim was to evaluate the possibility of using our ischemic non-healing wound model for preclinical studies of biomedical cell products (BCP) during transplantation of a tissue-engineered construct.

The tasks of the study were to conduct the experiment on the transplantation of the tissue-engineered construct “living skin equivalent” (LSE) and select methods for determining the effectiveness of treating ischemic non-healing wounds during preclinical studies on the proposed model.

The study was performed on 56 BALB/c mice divided into the following groups: “control” (n=19), “scaffold” (n=19), and “LSE” (n=18).

During the experiment, the histological, immunohistochemical methods and raster scanning optoacoustic mesoscopy (RSOM) technique were employed to compare the dynamics of regeneration of ischemic non-healing wound using LSE transplantation, collagen-hyaluronic film as a cell scaffold, and a non-treated wound.

Histology and immunohistochemistry have been found to be suitable to assess the effectiveness of treating ischemic non-healing wounds during preclinical investigations. The effect of LSE transplantation on infiltration of the wound bed with inflammatory cells, the formation of tissue in the wound bed zone, tissue condition at the wound margins, and angiogenesis has been studied. In addition, a new smoothing coefficient, i.e. the ratio of the thickness of the tissue-remodeling zone to the thickness of the dermis of the wound margins, has been proposed in the study. This coefficient makes it possible to assess the degree of filling the wound bed with the developing tissue. Its high value in the LSE group means that BCP transplantation influences the granulation tissue growth, prevents mechanical stress in the wound preventing thereby cosmetic defects.

Exploration of the regenerative processes has shown that the proposed model of the ischemic non-healing wound is suitable for preclinical studies of BCP.