OSTEOREGENERATIVE POTENTIAL AND REMODELING OF A COMPOSITE BASED ON NANOFIBRILLATED CELLULOSE, XENOGRAFT, AND...

The present study aimed to conduct a comparative histomorphological evaluation of bone regeneration after implanting a biocomposite with nanofibrillated cellulose, xenograft, and butvar-phenolic glue into a rat femoral bone defect. The analysis focused on the influence of the packing method (mixed or multilayer) on bone tissue formation, remodeling, biodegradation, and graft migration.

The experiment included 99 rats with a standardized femoral bone defect. The animals were divided into three groups: (1) negative control (defect without filling); (2) multilayer composite (layered packing of composite components); (3) mixed composite (implantation of a pre-mixed mass). Histological and histomorphometric evaluations were performed on days 30, 60, and 90 post-surgery. Additionally, an infected bone tissue wound was modeled; analogous groups, comprising 11 rats each, underwent histological evaluation on day 30.

Both composite packing methods (multilayer and mixed composite) facilitated accelerated cortical plate defect closure compared to the negative control on days 30 and 60 (p<0.01). In the mixed composite group, composite remodeling was more uniform and involved both peripheral and central zones of the composite. Material migration in this group was significantly less frequent than in the multilayer composite group (p<0.05). However, the mixed composite group more frequently exhibited fibroblastic barrier formation in the defect zone than the multilayer composite group (p<0.05). Layered packing was associated with greater composite biodegradation and reduced composite positional stability (including intra- and extraosseous migration). Under conditions of bacterial contamination, composite implantation was accompanied by a reduction in inflammatory response intensity and a decrease in necrosis area compared to the infected control group without filling.

This study demonstrated that mixed composites, including synthetic and biological components (nanofibrillated cellulose, xenograft, and butvar-phenolic adhesive), possess high osteoconductive and osteoinductive potential for bone tissue defect restoration. The obtained results indicate the material's biocompatibility and a low incidence of both early and late complications, including graft migration and degradation. Furthermore, under conditions of bacterial wound contamination, the composites exhibited pronounced barrier and antimicrobial properties, preventing bacterial colonization and the development of purulent-necrotic inflammation.