The effect of bone marrow mesenchymal stem cell and nano-hydroxyapatite/collagen I/poly-L-lactic acid scaffold implantation on the treatment of avascular necrosis of the femoral head in rabbits.

For avascular necrosis of the femoral head (ANFH), repair and regeneration are difficult because of the edema and high pressure caused by continuous ischemia and hypoxia. Core decompression (CD) is a classic method for treating early ANFH before the collapse of the femoral head; however, its effect is still controversial. To improve the therapeutic effect of CD on ANFH, a novel tissue-engineered bone (TEB) was constructed by combining bone marrow mesenchymal stem cells (BMSCs) with nano-hydroxyapatite/collagen I/poly-L-lactic acid (nHAC/PLA) scaffolds and implanting the TEB into the bone tunnel of CD. Cell attachment was observed by scanning electron microscopy and hematoxylin and eosin staining. The authors' previous studies confirmed that nHAC/PLA is an excellent scaffold material with favorable biocompatibility and no cytotoxicity. A total of 24 New Zealand rabbits with ANFH were randomly divided into three groups, as follows: Group A (n=8), pure CD; group B (n=8), CD+nHAC/PLA; and group C (n=8), CD+BMSCs-nHAC/PLA. The favorable effect of BMSCs-nHAC/PLA on angiogenesis and bone formation in necrotic areas was further evaluated via radiographic and histological analyses. Computerized tomography (CT) scanning and H&E staining showed more capillaries and new osteoid tissue in group C compared with in groups B and A. Micro-CT showed that the new bone coverage rate and implanted material degradation degree were each increased in group C compared with in group B. These results indicate that BMSCs-nHAC/PLA scaffolds may improve the curative effect of CD and provide a strategy for treating ANFH.