Angiogenesis role in the regulation structural changes of connective tissue in chronic surgical pathology ischemic genesis (experimental study)

The article presents the material that allows to form or supplement the idea of the role of angiogenesis in the regulation of structural changes in connective tissue in chronic surgical pathology of ischemic genesis. The significance and effectiveness of the use of bioengineered structures (mesenchymal multipotent stem cells), their role and influence on the process of connective tissue regeneration are considered. The model of ischemic pathology of connective tissue in vivo-mechanical damage of the calcaneal enetesoorganocomplex (patent for an invention №2779405) - allowed us to understand the mechanism of direct stimulation of neoangiogenesis by activating proangiogenic factors with local integration of labeled mesenchymal multipotent stem cells. Purpose. To research the role and influence of neoangiogenesis on the process of regeneration of structural elements of connective tissue in chronic surgical pathology of ischemic genesis, by morphological examination of the structures of periarticular tissues. Materials and methods. The experimental study was performed on 30 male Wistar stock rats weighing 200-300 g; divided into two equal groups-the main one (n=15) - labeled multipotent mesenchymal stem cells isolated on the basis of intraabdominal visceral fat from the stromal vascular fraction and the control one (n=15) were implanted-the healing process proceeded naturally. Modeling of acute mechanical calcaneal enthesitis was performed in the operating room, with the use of anesthesia and compliance with the rules of asepsis and antiseptics. Cell culture was cultured when confluence was reached-80%, in the experiment, cells of the third passage implanted in the zone of the entheoorganocomplex, simulated acute mechanical calcaneal enthesitis, were used. Transplanted cultures were labeled by transfection of a construct with a green fluorescent protein (GFP) in a lentiviral vector. On the 1st, 15th, 30th, and 60th days, animals were removed from the experiment and subsequent morphological studies were carried out: histological, morphometric, immunohistochemical. Results. Connective tissue repair, both in the main and in the control group, occurred by the 30th day. However, the fibrous regenerate of the surgical intervention area of the main group (n=15) differed in the structuring and ordering of collagen fibers, as well as the stability and density of newly formed vessels grouped mainly in the defect zone, in a fourfold predominant amount, starting from 15 days. Based on the data obtained, a fundamentally important fact was established-transplanted cells with fibro- and chondrogenic differentiation potential were directly involved in the reparative process. This circumstance complements the ideas about the participation of transplanted MMSCs in regenerative processes that have been formed to date, since it demonstrates their direct participation in the regeneration process in vivo, and not only in artificial cultural conditions.