Injectable composite hydrogel promotes osteogenesis and angiogenesis in spinal fusion by optimizing the bone marrow...

With the development of tissue engineering, it is no longer a challenge to repair and reconstruct bone defects using bone substitutes. However, in spinal fusion surgery, high rates of fusion failure are difficult to avoid. In our study, we designed a new composite hydrogel and found that it has good osteogenesis and angiogenesis effects. We extracted exosomes produced by rBMSCs (rat bone marrow mesenchymal stem cells) cocultured with the hydrogel to investigate their effects on osteogenesis and angiogenesis. The results showed that the PG/TCP (PEGMC with β-TCP) promoted rapid osteogenesis, facilitated spinal fusion at a high rate and quality and had an indirect effect on angiogenesis. We found that PG/TCP affected the rBMSC microenvironment, thus changing the function of exosomes; in a further study, we found that PG/TCP-MSC-Exos played a significant role in osteogenesis, which was coupled to angiogenesis. Thus, PG/TCP showed excellent potential in bone regeneration, especially the PG/0.2TCP.