Abstract
Previous preliminary studies have suggested that hydroxyapatite with a grooved structure (HAG) scaffold has good osteogenic potential. This type of scaffold may aid osteogenesis during the repair of large maxillofacial bony defects. The ectopic osteogenic effect and underlying mechanism were further studied using porous HAG scaffold-based delivery of human placenta-derived mesenchymal stem cells (hPMSCs). A total of 18 dogs were randomly allocated into a HAG scaffold group and a HAG scaffold-based hPMSC (HAG/hPMSC) group, and three scaffolds were implanted into the dorsal muscle of each dog. Samples were taken for subsequent analysis and tested 4, 8 and 12 weeks following heterotopic implantation. H&E staining was used to study the osteogenic effect in dog dorsal muscles, and RNA sequencing (RNA-seq) was used for exploring the underlying osteogenic mechanism. The osteogenic ability and effector of the HAG/hPMSC group were significantly greater than those of the HAG scaffold group at 4 weeks after implantation. After 12 weeks, a mature bone plate structure was seen in the HAG/hPMSC group. RNA-seq demonstrated that various osteogenesis-related pathways participated at different stages of metabolism, and that the expression of collagen-1 and runt-related transcription factor 2 increased with implantation time. The present study preliminarily focused on the ectopic osteogenic effect of the porous HAG scaffold-based delivery of hPMSCs in vivo, which may be helpful for the improved application of HAG scaffolds in the future.