Dynamics of acute-phase and endothelial responses and immune complex development during bone replacement of bone fragment fractures in dogs using germanium-doped calcium-phosphate ceramics

Abstract

Fragmentary bone fractures are associated with a higher rate of postoperative morbidity because of bone defect formation. Therefore, bone replacement, specifically doped calcium-phosphate ceramics, is required to restore bone structure and function. This study aims to biochemically evaluate acute-phase and endothelial responses, as well as immunological complex development, after bone replacement of bone fragment fractures in dogs using germanium-doped calcium-phosphate ceramics. Plate osteosynthesis was used on dogs with long tubular bone fragment fractures. Bone defects in the experimental group (n = 10) were filled with germanium-doped calcium phosphate ceramics (H/-TCP/l-Gе-700), whereas those in the control group (n = 10) were left unfilled. following the injury and again 3, 7, 14, 30, and 60 days following osteosynthesis, blood samples were collected. Recovery of limb function was 1.3 times quicker (P 0.001) and complete recovery was 1.2 times faster (P 0.01) in the experimental group compared to the control. Bone regenerate in the control animals did not have adequate density and had a strong periosteal response, whereas in the experimental animals the defect was filled with a regenerate of high X-ray density on day 60. Albumin and total protein levels were similarly within the normal range in both samples. Protein C activity in the experimental group was 1.3% higher (P 0.001) on day 3, and 2% higher (P 0.001) on day 7 compared to the control group, before returning to baseline by day 14. By day 60, the concentration of ceruloplasmin in the experimental mice had returned to normal after initially being 1.1-fold ( 0.001) greater than in the control animals. After injury, small molecular circulating immune complexes (CIC) increased 1.1-fold ( 0.001), peaking on day 14 for both the control and experimental groups. By day 60, the CIC level in the experimental group had returned to pre-injury levels. Nitric oxide (NO) levels rose from day 3 to day 30 (with a high on day 7) in the experimental group and from day 7 to day 60 (with a peak on day 30) in the control group. When fragments of long tubular bones are implanted with calcium-phosphate ceramics doped with geranium, the inflammatory-resorptive stage of reparative osteogenesis is mildly suppressed and the proliferative stage is strongly stimulated.