Application of Nano-Calcium Phosphate Coated Porous Tantalum Scaffold in Repair of Rabbit Cartilage Defect

Abstract

Calcium coated scaffolds and their role in repair of bone defects have been widely studied in the last decades. This study aimed to evaluate the effect of bone morphogenetic protein-7 (BMP-7) loaded nano-calcium phosphate (CaP) coated porous tantalum scaffolds (PTS) on regenerative and reparative potency of cartilage defects in rabbits. We used New Zealand white rabbit cartilage defect models. The subjects were randomly grouped into 4: (1) a control group (no treatment), (2) a PTS group, (3) a CaP/PTS group, and (4) a CaP/PTS/BMP-7 groups. The characterization and in vitro biocompatibility of each scaffold were evaluated. Following scaffold implantation, we evaluated the gross observation score, Micro-CT observation parameters, and the mRNA of target genes. No visible difference was detected in water contact angle (WCA) and cell proliferation activity after co-culture among the PTS, CaP/PTS, and CaP/PTS/BMP-7 scaffold groups (P >0.05). Gross observation scores, trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular mineral density (TMD), bone volume fraction (BV/TV), COL2A1, SOX-9, Aggrecan, and RUNX-2 showed an obvious increase among the PTS, CaP/PTS, and CaP/PTS/BMP-7 groups to those with no treatment (P <0.05). Also, the PPARγ showed an obvious decline (P <0.05). Gross observation scores, Tb.Th, Tb.N, TMD, BV/TV, COL2A1, SOX-9, Aggrecan, and RUNX-2 increased and PPARγ decreased in CaP/PTS/BMP-7 group to PTS and CaP/PTS groups (P <0.05). Our findings indicate that PT scaffolds enhance the reparative potency of cartilage defects in New Zealand rabbits promoted the repair of cartilage defects in rabbits. This effect is boosted among those treated with the BMP-7 loaded nano-CaP coated PTS, and this group showed improved regenerative and reparative potency.