Carp Collagen Membrane for Guided Bone Regeneration: Evaluation in a Rat Femoral Defect Model

• Carp-derived collagen membrane supports bone healing in a rat femoral defect model with good biocompatibility. • Membrane-only treatment showed a consistent trend toward higher bone formation and healing scores. • Addition of Bio-Oss® did not improve healing outcomes in this non–critical-size defect model. • Further studies in clinically relevant models are required to confirm these findings. : Guided bone regeneration (GBR) relies on barrier membranes to stabilize the blood clot and maintain a protected healing space. Collagen membranes are typically derived from mammalian sources; however, concerns regarding zoonotic transmission, ethics, and cost have driven interest in alternative materials. Fish-derived collagen has emerged as a potential substitute. A novel membrane from European carp ( Cyprinus carpio ) skin has shown favorable soft-tissue outcomes, but its performance in bone healing has not yet been evaluated. : Standardized cortical defects were created in the femora of 21 Wistar rats. Four treatments were evaluated: empty defect, carp collagen membrane alone, Bio-Oss® + carp collagen membrane, and Bio-Oss® + Bio-Gide®. Animals were euthanized at 4, 12, and 16 weeks. Healing was assessed by micro-CT and histology. Descriptive statistics (median, IQR) were used, and group comparisons were performed using non-paramertic Kruskal–Wallis tests with Dunn’s post-hoc testing; effect sizes were reported as η². : Defects treated with the carp collagen membrane alone showed a consistent trend toward higher median healing scores, greater new bone formation, and smaller residual defect size, although differences were not statistically significant. When combined with Bio-Oss®, outcomes were less favorable than with Bio-Oss® + Bio-Gide®. : The carp collagen membrane supported bone healing in a non–critical-size rat femoral defect model and demonstrated favorable biocompatibility. These findings suggest that fish-derived collagen may represent a promising alternative membrane material, particularly in indications where membrane function alone is sufficient. Further validation in large-animal critical-size defect models is required.