Gene-modified BMSCs encapsulated with carboxymethyl cellulose facilitate osteogenesis in vitro and in vivo

Critical size bone defects are one of the most serious complications in orthopedics due to the lack of effective osteogenesis treatment. We fabricated carboxymethyl cellulose with phenol moieties (CMC-ph) microcapsules loaded with gene-modified rat bone mesenchymal stem cells (rBMSCs) that secrete hBMP2 following doxycycline (DOX) induction. The results showed that the morphology of microcapsules was spherical, and their diameters have equally distributed in the range of 100-150 mu m; the viability of rBMSCs was unchanged over time. Through real-time PCR and Western blot analyses, the rBMSCs in microcapsules were found to secrete hBMP2 and to have upregulated mRNA and protein expression of osteogenesis-related genes in vitro and in vivo. Furthermore, the in vivo results suggested that the group with the middle concentration of cells expressed the highest amount of osteogenic protein over time. In this study, we showed that gene-modified rBMSCs in CMC-ph microcapsules had good morphology and viability. The BMP2-BMSCs/CMC-Ph microcapsule system could upregulate osteogenic mRNA and protein in vitro and in vivo. Further analysis demonstrated that the medium concentration of cells had a suitable density for transplantation in nude mice. Therefore, BMP2-BMSCs/CMC-Ph microcapsule constructs have potential for bone regeneration in vivo.

Automated summary

In this study, gene-modified rat bone mesenchymal stem cells loaded with hBMP2 in microcapsules were shown to upregulate osteogenic gene expression in vitro and in vivo, indicating their potential for bone regeneration. The medium concentration of cells demonstrated the highest expression of osteogenic protein over time, suggesting a suitable density for transplantation in nude mice. The BMP2-BMSCs/CMC-Ph microcapsule system could be a promising option for bone repair.