X-ray macromorphological and biochemical assessment of consolidation of fractures of long tubular bones under conditions of osteoreplacement with calcium-phosphate ceramics doped with germanium for osteoporosis in rab-bits
Abstract
Among several factors that can cause a violation of the course of reparative osteogenesis, previous diseases associated with a change in the structural and functional state of bone tissue and primarily osteoporosis are considered significant. Osteoporotic fractures are difficult to treat. Along with systemic therapy, locally applied bone substitute materials, particularly unalloyed and alloyed calcium phosphate ceramics with pronounced osteoconductive, osteoinductive, and osteointegration properties. The work aims to evaluate the effect of calcium-phosphate ceramics doped with germanium on post-traumatic bone regeneration in conditions of secondary osteoporosis in rabbits. Experimental osteoporosis in rabbits was induced by administration of 0.4 % dexamethasone solution (KRKA, Slovenia) for 21 days at a dose of 1.2 mg/kg of body weight. Experimental (n = 9) and control (n = 9) groups of animals were formed. Animals of the experimental group had defects replaced with granules of hydroxyapatite ceramics, synthesized based on hydroxyapatite and β-tricalcium phosphate, doped with germanium. In rabbits of the control group, bone defects healed under a blood clot. Blood samples to determine the level of total calcium (Ca) and inorganic phosphorus (P) were taken before surgery and on 7-,14th, 30th, and 60th day of the study. X-ray studies were performed on the RUM-20 X-ray machine on the 14th, 30th, and 60th day of reparative osteogenesis. Radiologically and macromorphologically, it was established that reparative osteogenesis in the experimental animals proceeds more dynamically compared to the control group and is characterized by a high density of bone tissue at the site of the defect already on the 14th day after the injury, a moderate periosteal and early appearance of the endosteal reaction. The content of total calcium in the animals of the experimental group on the 14th day after the injury was 1.3 times (P < 0.001) higher than that of the control and animals before the operation, and on the 30th day, it was 1.2 times (P < 0.001) in accordance. The concentration of inorganic phosphorus (P) on the 14th and 30th days of reparative osteogenesis in animals of the experimental group was 1.1 times (P < 0.05) lower than in control animals, and on the 60th day in 1.4 times (P < 0.01), respectively. Systemic osteoporosis in experimental animals causes a violation of reparative osteogenesis due to the prolongation of the inflammatory-resorptive stage and cartilaginous callus and complicated mineralization of bone regeneration. Calcium-phosphate ceramics is a promising material for replacing bone defects in animals with systemic secondary osteoporosis.
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