Structure and Morphogenetic Properties of Collagen Matrixes Obtained from Connective Tissue Sheaths of Paravertebral Tendons

The morphogenetic properties of a collagen gel prepared by acetic acid extraction from the tendon sheaths (peritenons) of the paravertebral tendons of Wistar rats were studied. The gel was used as a substrate during in vitro cultivation together with mesenchymal stromal cells for 14 days in the growth and osteogenic incubation media. It has been established that the collagen framework of the peritenon substrate is strengthened by increasing the connectivity of fibrillar nodes and is structured with the formation of lamellar and tangle formations. Sesamoid globules, penetrating into the substrate from the initial peritenon gel, during cultivation remain inert in the growth medium, but exhibit an increased ability to structure calcium phosphates in the osteogenic medium. The formation of cell-mediated structures occurs by directions of fibro-, tendo-, ligament- and osteogenic differentiation. The fibrogenic direction provides a structuring framework; the tenogenic direction – the formation of embryonic tendons according to the mechanism of lateral assembly of collagen subfibrils on cell surfaces and their autonomization in the form of tendon filament primordia; the ligamentogenic direction – structuring of collagen ribbons associated with tangles and elastic fibers; the osteogenic direction – the formation of lamellar, trabecular and nodular osteoid structures through intramembranous ossification, accompanied by activation of alkaline phosphatase and mineralization. The formation of enthesis predictors is the organization of commissures between mechanically different-phase components of osteoid structures and frame. A classification of taxonomic forms has been developed and a hypothesis has been proposed about the role of evolutionary tools in the structuring of the collagen framework in tissue cultures in vitro. The classification of taxonomic forms has been developed and a hypothesis has been proposed about the role of evolutionary tools in the structuring of the collagen framework in tissue cultures in vitro.