In vivo assessment of marine vs bovine origin collagen-based composite scaffolds promoting bone regeneration in a New Zealand rabbit model

The ability of human tissues to self-repair is limited, which motivates the scientific community to explore new and better therapeutic approaches to tissue regeneration. The present manuscript provides a comparative study between a marine-based composite biomaterial, and another composed of well-established counterparts for bone tissue regeneration. Blue shark skin collagen was combined with bioapatite obtained from blue shark's teeth (mColl:BAp), while bovine collagen was combined with synthetic hydroxyapatite (bColl:Ap) to produce 3D composite scaffolds by freeze-drying. Collagens showed similar profiles, while apatite particles differed in their composition, being the marine bioapatite a fluoride-enriched ceramic. The marine-sourced biomaterials presented higher porosities, improved mechanical properties, and slower degradation rates when compared to synthetic apatite-reinforced bovine collagen. The in vivo performance regarding bone tissue regeneration was evaluated in defects created in femoral condyles in New Zealand rabbits twelve weeks post-surgery. Micro-CT results showed that mColl:BAp implanted condyles had a slower degradation and an higher tissue formation (17.9 ± 6.9 %) when compared with bColl:Ap implanted ones (12.9 ± 7.6 %). The histomorphometry analysis provided supporting evidence, confirming the observed trend by quantifying 13.1 ± 7.9 % of new tissue formation for mColl:BAp composites and 10.4 ± 3.2 % for bColl:Ap composites, suggesting the potential use of marine biomaterials for bone regeneration.