Dynamics of hematological parameters and acute phase reactions for osteosubstitution by autofibrin and hydroxyapatite ceramics with β-tricalcium phosphate fragmentary bone fractures in dogs

Osteo-replacement materials are considered to be the most promising direction in solving the problem of restoring the regenerative potential of bone tissue, especially fragmentary fractures. However, the mechanism of their influence on the histomorphology of bone regenerates and the pathochemical phase of reparative osteogenesis require further and comprehensive justification. The aim of the study was to establish the dynamics of hematological parameters and acute phase response to osteosubstitution by hydroxyapatite ceramics with β-tricalcium phosphate and platelet-enriched autofibrin in fragmentary bone fractures in dogs. Control and research groups of animals were formed, each of which included dogs with fractures of both shoulder and forearm bones, which came in 2019- 2021 to the clinic of small pets of the Faculty of Veterinary Medicine of Bila Tserkva NAU. After general and local anesthesia, extracortical osteosynthesis and replacement of bone defects were performed: in the first experimental group (n = 10) autofibrin enriched with platelets (PRF), and in the second (n = 10) - its combination with hydroxyapatite ceramics (PRF + HA/β -TCP-700); in the control group (n = 10) the defects were left to heal under the blood clot. Blood samples for hematological and biochemical studies were taken after injury no later than 24 hours and on the 3rd, 7th, 14th, 21st and 42nd day after osteosynthesis. In peripheral blood, the number of erythrocytes, platelets and leukocytes was determined by conventional methods, and hemoglobin - hemoglobin cyanide. The content of nitric oxide (NO) in the blood serum was determined by the method of Green in the modification of Golikov, haptoglobin - by reaction with rivanol kits PJSC "Reagent" (Ukraine) and α2-macroglobulin - by KM Veremeenko. Statistical processing of the results was performed using the program Statistica 10 (StatSoft Inc, USA, 2011). It was found that bone trauma in dogs is accompanied by a decrease in peripheral blood of erythrocytes by 1.3 times (p <0.001) and an increase of 1.1 times (p <0.05) the number of leukocytes with a tendency to increase hemoglobin and platelets, compared with indicators of clinically healthy animals. After osteosynthesis in all groups leukocytosis developed. During osteosubstitution, the intensity and duration of the leukocyte reaction decreased significantly. In the first experimental group, the peak of NO concentration occurred on the 21st day, and in the case of combined osteosubstitution, the phase of its changes was noted, which had two peaks: on the 7th in 1.5 and on the 21st in 1.8 (p <0.001) is several times higher than in the control group. The concentration of haptoglobin after bone injury in dogs increased 1.1 times (p <0.001) compared with clinically healthy animals and reached its peak in all groups on the 3rd day (p <0.001). No changes in α2-macroglobulin concentration were observed in the groups during the entire study period. Combined osteosubstitution by calcium-phosphate ceramics with platelet-enriched fibrin induces early osteogenic processes at a lower intensity of the acute phase reaction at the phase peaks of nitric oxide - an inducer of angiogenesis, which indicates the viability of animals. Key words: nitric oxide, acute phase proteins, reparative potential, platelets.