Comparative Assessment of the Microbiological and Histopathological Picture of the Implantation Zone of a Nanocellulose-based Biocomposite <i>In Vivo</i>

BACKGROUND/AIM: Bone tissue defects remain one of the main challenges in modern traumatology, often requiring biocompatible materials to restore bone integrity and function. The development of nanostructured composites opens new opportunities for bone regeneration. In our previous study, a nanocellulose-based biocomposite showed the ability to accelerate bone repair and achieve complete closure of bone defects. The present study aimed to evaluate the effect of this material on the microbial composition and inflammatory response at the implantation site. MATERIALS AND METHODS: Twenty-eight rats were used and divided into two equal groups (n=14). In group 1, the defect was filled with an autologous blood clot (ABC), and in group 2 - with a nanofibrilated cellulose-based biocomposite (NFC). The microbial composition at the implantation site was assessed by standard microbiological techniques using Chistovich yolk-salt agar, McConkey agar, blood agar, and Sabouraud medium. Histological evaluation of the inflammatory response was performed on days 14 and 30 after implantation. RESULTS: was isolated once. No fungal growth occurred on Sabouraud medium. Histological analysis revealed no necrosis or active inflammation. Mild lymphocytic infiltration in the NFC group on day 14 indicated a normal early post-implant reaction. CONCLUSION: At days 14 and 30 post-implantation of a nanofibrilated cellulose-based biocomposite, the microbiological profile of the defect site remained within physiological norms in both groups. Occasional hemolytic isolates were considered technical contamination. The nanocellulose-based biocomposite did not disrupt the local microbial balance, supporting its biocompatibility and safety for use in bone tissue regeneration.