Comparison of osteogenic activity from different parts of induced membrane in the Masquelet technique.

BACKGROUND: The Masquelet technique is widely used to treat long-bone segmental defects because of its high success rate and low surgical difficulty. However, the cause of the uneven growth of bone grafts following this procedure remains unclear. METHODS: Rats were randomly divided into four groups for analysis 2-, 4-, 6- and 8-weeks postoperatively and underwent a uniform surgical procedure to construct a 10 mm bone defect in the right posterior branch of the femur. Induced membrane specimens were harvested at the appropriate time points and divided into segments according to their location. Bone growth activity was assessed by immunohistochemistry, western blotting, and quantitative real-time polymerase chain reaction. RESULTS: Mature blood vessels were more densely distributed at the proximal end of the bone defect than at other locations at all time points. The number of blood vessels on the same side of the longitudinal axis of the femur also varied depending on location. The difference between the proximal-anterior and distal-anterior regions within the induced membranes was most pronounced at 6 weeks postoperatively and decreased by 8 weeks postoperatively. The differences between the proximal-posterior and distal-posterior regions within the induced membranes were more pronounced. The expression of the growth factors bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor A(VEGFA), and transforming growth factor-ß1(TGF-ß1) in the proximal-posterior regions of the bone defect was almost always higher than that in other regions at the same time point. The expression of BMP-2 in the posterior regions of the bone defect was always higher than that in the anterior regions at the same end of the femoral longitudinal axis. CONCLUSION: The number and maturation of vessels in the proximal region of the induced membrane at the bone defect site were higher than those in the distal region, and the expression of growth factors was higher, with the highest induced membrane activity in the proximal-posterior regions of the bone defect. Therefore, there was inhomogeneity in induced membrane activity.

Hyaluronic acid hydrogel encapsulated BMP-14-modified ADSCs accelerate cartilage defect repair in rabbits.

BACKGROUND: Cartilage defect has a limited capacity to heal. In this context, we hypothesized that hyaluronic acid (HA) hydrogel encapsulated BMP-14-modified adipose-derived mesenchymal stem cells (ADSCs) could accelerate cartilage defect repair in rabbits. METHODS: ADSCs were isolated and identified by flow cytometry. ADSCs were treated with adenovirus vector encoding BMP-14 (Ad-BMP-14) or adenovirus vector encoding control (Ad-ctrl). Real-time PCR (RT-PCR) and western blot assay was performed to verify the transfection efficacy and chondrogenic differentiation markers (ACAN, Collagen II and SOX9). Rabbit cartilage defect model was performed and randomly divided into following groups: control group, HA hydrogel + ADSCs, ADSCs, HA hydrogel + BMP-14 transfected ADSCs, HA hydrogel + BMP-14 transfected ADSCs. At 6, 9 and 12 weeks after surgery, scanning electron microscopy, hematoxylin-eosin, Safranin-O/Fast Green and immunohistochemical staining for Collagen II were performed to determine the role of HA hydrogel encapsulated BMP-14-modified ADSCs in cartilage repair in vivo. RESULTS: ADSCs were successfully isolated and positively expressed CD29, CD44 and CD90. Transfection efficacy of Ad-BMP-14 was verified by RT-PCR and western blot assay. Moreover, Ad-BMP-14 could significantly increased chondrogenic differentiation markers (ACAN, Collagen II and SOX9). The LV-BMP-14-ADSCs and HA hydrogel + LV-BMP-14-ADSCs groups revealed smoother surface cartilage repair that was level with the surrounding cartilage and almost complete border integration. CONCLUSIONS: HA hydrogel encapsulated BMP-14-modified ADSCs accelerate cartilage defect repair in rabbits. We need to further validate the specific mechanism of action of HA hydrogel encapsulated LV-BMP-14-ADSCs involved in the repairing cartilage damage in vivo.