Histological Characteristics of Experimental Wounds of Soft Tissues of the Femur of Rats and the Role of IFN-γ in the Dynamics of their Healing

Abstract

The purpose of the study was to evaluate the histomorphological changes in samples of the wound canal of the soft tissues of the femur of rats and to study the role of interferon-gamma (IFN-γ) in the dynamics of wound healing. Materials and methods. The study was conducted on 24 Wistar rats. Animals were divided into two groups – intact (6 rats) and experimental (18 rats). Animals of the experimental group were used to simulate wounds. Rats were euthanized on the 10th, 20th, and 40th days (6 animals for each time) after wound simulation. Blood for the study was taken by the method of open cardiac puncture. The levels of INF-γ in the blood serum of animals were determined by enzyme immunoassay. Histological processing of the samples was carried out according to generally accepted methods, the sections were stained with hematoxylin and eosin, as well as picrofuchsin according to Van Gieson. Results and discussion. The work revealed changes in the expression of IFN-γ in the blood serum of animals with wounds: an increase in the levels of IFN-γ on the 10th and 20th days after modeling wounds compared to the levels of rats in the intact group (p<0.05). A decrease in the levels of IFN-γ on the 40th day of the experiment compared to a similar level of this cytokine on the 10th and 20th days after wound simulation was shown (p<0.05). The results of histological studies show signs of the proliferative phase in the form of a significant number of fibroblasts and newly formed vessels, as well as the beginning of the remodeling stage in the form of the organization of collagen fibers in parallel bundles in the wound canals in different areas within 10 days. On the 20th day, the absence of inflammatory cells in the preparations of the damaged areas is noted. Also at the tissue level at this time, signs of the remodeling phase were revealed: a significant decrease in the number of blood vessels and fibroblasts was observed, the connective tissue in the areas acquired a mature appearance in the form of dense layers with single fibrocytes. In the injury zone on the 40th day of the experiment, scars from mature connective tissue were noted. Conclusion. In an experimental study, we showed the morphological and physiological features of the healing of soft tissue injuries in normal rats. The established structural features of wound areas at different stages of healing and the dynamics of IFN-γ release allow us to determine its important role not only in inflammation, but also in the stages of proliferation and remodeling. Determination of the concentration of IFN-γ may be an informative indicator at all stages of repair in the process of healing soft tissue injuries in humans, subjected to further clinical studies