A wide list of clinical cases with bone injuries, as well as the absence of a universal osteoplastic material, leads to an active search for new materials with high biocompatibility, timely resorption, and the presence of osteoinductive properties. The regenerative potential of the material is associated with the presence in its composition of biologically active components - recombinant proteins – inducers of osteogenesis (BMP-2) and angiogenesis (erythropoietin, EPO). Materials based on bioactive silicate ceramics, for example, diopside (CaMgSi₂O₆), which provides a prolonged biological effect due to the slow release of immobilized proteins, can act as promising carriers. Such materials can be used both independently and in composites containing other biocompatible components (demineralized bone matrix, DBM; hyaluronic acid, HA).
We have developed a new composite osteoplastic material based on BMP-2 and EPO, immobilized on diopside particles, introduced into a scaffold based on DBM with the addition of HA. The immobilization capacity and kinetics of BMP-2 release from the diopside were studied under various conditions.
The study of biocompatibility and osteoinductive properties of the developed materials was carried out in vivo on a model of ectopic osteogenesis in mice (40 outbred male ICR (CD-1) mice of 38-47 days old). Experimental animals were divided into 5 groups, 8 animals per group: Group 1 - DBM + HA; Group 2 - DBM + HA + diopside; Group 3 - DBM + HA + diopside + BMP -2; Group 4 - DBM + HA + diopside + EPO; Group 5 - DBM + HA + diopside + BMP-2 + EPO. The implants were 1 х 1 х 4 mm DBM blocks inserted into the gluteal muscle of the hind paws of the animal (two implants per animal). Euthanasia, tomography and histomorphometry were performed 12 weeks after the operation. According to the results of tomography and histological analysis all implanted biocomposites demonstrated their high biocompatibility. The addition of rhBMP-2 to the scaffolds resulted in significant osteogenic effect and formation of large mineralization areas. The addition of erythropoietin led to an increase in the quality of the newly formed bone tissue, as well as, in some cases, to an increase in the amount of mineralized bone.