The effect of implantation into the interfragmentary spaces of platelet-rich various forms autofibrin and its composite with calcium phosphate ceramics for osteoreplacement on reparative osteogenesis has been clinically and experimentally substantiated. This is novel in solving the optimizing consolidation problem of long tubular bones’ various types fractures in animals.
With the help of clinical-radiological, macro- and histomorphological methods of research and data analysis of hematological, biochemical and molecular-biological indicators, it has been proven that platelet concentrates after implantation in bone defects realize their osteoinductive properties with the beginning of neoangiogenesis and the formation of an early osteoblastic reaction.During composite osteoreplacement, similar processes occur in lamellar bone tissue. This course of reparative osteogenesis is confirmed by reactive thrombocytosis, phase peaks of nitric oxide and biochemical markers of bone metabolism, elimination of the imbalance between osteoresorptive and osteogenic processes.
The cytological and histological studies results established areas of platelet concentration in PRP and PRF samples at different values of the relative centrifugal centrifugation force. In particular, in the range of 100–1843 g of centrifugal centrifugation force in blood samples, the highest concentration of platelets in the obtained rabbit plasma is achieved for 100 g for 3 min – 824±30.4 G/l, and 400 g (10 min) – 550±21.2 G/l, for their content in whole blood – 210±9.6 G/l (p<0.001). At the same time, with an increase in this value, the content of platelets in the blood plasma decreases sharply within 10 minutes: from 322±18.8 G/l for 735 g to 20±4.5 G/l for 1843 g (p<0.001).
Different values of the relative centrifugal force of blood centrifugation also significantly affect the distribution of cellular elements in fibrin clots. As the centrifugation parameters increase, areas of platelet concentration shift toward the erythrocyte mass. In addition, when centrifuging blood samples in the range of 100–1843 g of centrifugal force, the length of fibrin clots increases with a uniform distribution of platelets in fibrin clots obtained at 400 g. This justifies the optimal modes of blood samples centrifugation in the range of 100–400 g to obtain platelet-rich plasma or fibrin.
For the first time, a clinical and radiological study established that the implantation of PRP materials in rabbits’ bone defects of compact or cancellous bone is characterized by early peri- and endosteal reactions as well as the osteoid’s formation with varying degrees of radiopacity, compared to their healing under a blood clot. Moreover, in the case of osteoreplacement with the PRF+HA/β-TCP–700 composite, an early and powerful development of osteogenic processes is observed, which occurs mainly due to endosteum with point osteosclerosis already on the 21st day. However, when xenogenic PRF is implanted into bone defects of rabbits, the inflammatory-resorptive processes are prolonged in time, which inhibits the osteogenic reaction, and the X-ray negativity of the bone defect is established even on the 42nd day with a zone of increased X-ray density around it.
Currently, the point macromorphological assessment of bone regenerates based on their volume, density and degree of contact with the parent bone actually did not depend on the substance of the bone tissue - spongy or compact. Upon that, with the implantation of auto-PRF or composite osteoreplacement, the macromorphological indicators of the bone regenerates’ density and their connection with the mother bone are 1.3–1.4 and 1.3–1.8 times higher than those of controls, respectively. In addition to the above, reparative osteogenesis in rabbits after auto-PRF materials’ implantation into bone defects is histomorphologically characterized by an earlier osteoblastic reaction with the formation of cancellous bone tissue elements on the 14th day and osteons on the 42nd. In the case of xeno-PRF implantation, an excessive and prolonged chondroid reaction is observed up to the 42nd day, while in the case of composite osteosubstitution – an earlier osteoblastic reaction and neoangiogenesis on the 14th day with the formation of lamellar bone tissue’s elements and, in particular, within the granules of by their gradual biodegradation and the osteons’ formation during the 21st day. By scoring the histological criteria of bone regenerates on the 42nd day, the type of newly formed tissue, the volume of trabeculae and osteons, the density of placement and the number of cells in their thickness and on the surface does not depend on the type of spongy or compact substance of lamellar bone tissue. However, during the implantation of xenological PRF, its indicators on the 42nd day of reparative osteogenesis were 1.3–1.4 times lower than in the control group (p<0.001).
