Effect of bone marrow mesenchymal stem cells transfected with rAAV2-bFGF on early angiogenesis of calvarial defects in rats

The purpose of this study was to evaluate the effect of bone marrow mesenchymal stem cells (MSCs) transfected with the basic fibroblast growth factor (bFGF)-expressing recombinant adeno-associated virus vector (rAAV2-bFGF), on early angiogenesis of calvarial defects in rats. The MSCs were cultured and transfected with rAAV2-bFGF after differential adherence isolation. The transfection efficiency was detected by RT-PCR and Western blotting. The transfected MSCs were compounded with poly-DL-lactide/hydroxyapatite (PDLLA/HA) in vitro. The cranial defect models in 36 male SD rats were created. Nothing (group A), PDLLA/HA alone (group B), PDLLA/HA combined with MSCs (group C), and PDLLA/HA combined with rAAV2-bFGF transfected MSCs (group D) were implanted in rat calvarial defects. The specimens were harvested for hematoxylin-eosin staining on the day 1, 3 and 7 after implantation. Factor VIII immunohistochemical staining and histomorphometric analysis were carried out to evaluate neovascularization around the implantation. The results indicated that MSCs could indeed be successfully transfected with the rAAV2-bFGF vector. Histological and histomorphometric analysis revealed that the angiogenesis in group D was significantly enhanced as compared with the rest groups (P<0.05). These results strongly suggest that MSCs transfected with rAAV2-bFGF in combination with PDLLA/HA can effectively promote the early angiogenesis of calvarial defects in rats, which played an important role in creating an environment suitable for the survival and activity of transplanted cells for further applications in cranio-maxillofacial bone regeneration.