Histomorphological characteristics of bone replacement in rabbits with hydroxyapatite ceramics and Platelet-Rich Fibrin

Abstract

The results of a histomorphological study of bone regenerates in rabbits after osteosubstitution with platelet-rich fibrin and its combination with hydroxyapatite granules with β-tricalcium phosphate in spongy and compact bone tissue at different periods of reparative osteogenesis are presented. Three groups of rabbits were formed. In the control group, the defects were left to heal under the blood clot. Bone lesions in the first experimental group were filled with platelet-rich fibrin, in the second – with a combination of platelet-rich fibrin and hydroxyapatite with β-tricalcium phosphate. All animals were kept in the same conditions of feeding and housing, had unlimited access to water. During the study, the rabbits were monitored clinically. The animals were taken out of the experiment on the 14th, 21st and 42nd days, samples of bone tissue were taken, they were fixed, decalcified, dehydrated in alcohols of increasing concentration and embedded in paraffin. In the presented study, it is most likely that the newly formed bone tissue is formed precisely due to osteoinduction in the experimental groups. When using granules of hydroxyapatite and β-tricalcium phosphate with platelet-rich fibrin, bone regenerate is between the composite granules and is not associated with contact with the maternal bone. Its cells appear in different places of the defect. In the spongy bone tissue on the 21st day, regeneration proceeded more fully and faster in the second experimental group, as evidenced by the significant density of cells of the osteoblastic row, the thickness of the bone trabeculae and their volume, filling the site of the defect. On the 42nd day, in the second experimental group, when using a combination of autobiomaterial and hydroxyapatite granules with β-tricalcium phosphate, the regenerate contained a significantly larger number of osteogenic cells in the thickness of the trabeculae, which indicated a more intensive course of reparative osteogenesis in comparison with the first experimental and control groups. In the compact bone on day 21, regeneration was more complete and faster in the second experimental group. On the 42nd day, according to the degree of maturity of the bone regenerate, calcium-phosphate ceramics in combination with platelet-rich fibrin optimizes reparative osteogenesis most clearly. According to the degree of intensity of the osteoregeneration process, the groups can be placed in the following sequence: control ˂PRF˂PRF+HA/β-TCP–700. According to histomorphological characteristics, the combination of hydroxyapatite with β-tricalcium phosphate and platelet-rich fibrin gives greater osteoinduction to the composite material, which is confirmed by the high cell density, namely of osteoblasts and osteocytes. The use of PRF in combination with other materials may become promising for the correction of reparative osteogenesis in conditions of limited or reduced regenerative potential of bone tissue.