BACKGROUND
The problem of searching for new approaches to the treatment of trophic ulcers associated with venous circulation pathology does not lose its relevance. Currently, the search is aimed at optimizing the wound healing process based on cell-replacement therapy. However, data on the ultrastructural features of biopsy specimens of healing ischemic skin defects during transplantation of dermal equivalent with dermal fibroblasts and with the support of polydeoxyribonucleotides are single and rare, which makes our study relevant.
OBJECTIVE
The aim of the study: to evaluate the effectiveness of the alloplasty method of an ischemic skin defect based on the study of the biopsies morphology and the ultrastructural characteristics of the regenerative histion of the biopsies dermis on the 23rd day of the ischemic defect healing in mice after transplantation of a dermal equivalent with cultured allofibroblasts and with the support of polydeoxyribonucleotides.
MATERIAL AND METHODS
An ischemic skin defect was modeled in 12 C57/B1 mice divided into control and experimental groups. For the experimental group, dermal allofibroblasts were obtained using the enzymatic method and cultured in DMEM/F12 medium (Lonza). Cells of the second or third passage were used to form a dermal equivalent. In the experimental series, the model wound was injected with 0.39 ml of Polydeoxyribonucleotides “Plenhyage Medium” from I.R.A. Istituto Ricerche Applicate Sri (Italy). Biopsies were obtained surgically on the day 23 of healing. Ultrathin sections were studied in a Selmi electron microscope (Ukraine) at an accelerating voltage of 125 kV. A part of the scar biopsy was fixed with 10% neutral formalin, embedded in paraffin, sections were stained with Mayer’s hematoxylin and eosin. Using the MS Office Excel 2007 program and Statistica 10.0 Enterprise (StatSoft Inc., USA), the thickness of the epidermis and the specific area of granulation tissue components on the day 23 of reparative histogenesis were studied. The normality of data distribution was checked using the Shapiro-Wilk criterion. The Mann—Whitney criterion was used for pairwise comparisons, and group data were described using the median, the first and third quartiles (interquartile range). All calculations were performed in the R Statistical Environment, Version 4.2.3. The data obtained were visualized using the Ggplot2 package.
RESULTS
It was found that after transplantation of a dermal equivalent with dermal allofibroblasts supported by polydeoxyribonucleotides into an ischemic skin defect, the median thickness of the stratified squamous nonkeratinized epithelium of the epidermis, the median area occupied by collagen fibers in the dermis of biopsies and the median area occupied by blood vessels was statistically significant differ to those during healing of the model wound without treatment. During electron microscopic examination of the dense irregular connective tissue dermis biopsies of the experimental group binuclear fibroblasts are found. It allows them to achieve accelerated healing of extensive tissue defects against the background of circulatory insufficiency.
CONCLUSION
Transplantation of dermal equivalent with dermal allofibroblasts supported by polydeoxyribonucleotides into an ischemic model wound accelerates skin defect healing by 22.3±0.01%.
