Osteoblast-oriented differentiation of BMSCs by co-culturing with composite scaffolds constructed using silicon-substituted calcium phosphate, autogenous fine particulate bone powder and alginate in vitro

Abstract

Autogenous bone graft is the best for spinal fusion in clinics, however, lacking sources, bleeding and infection are limited its practice. Seeking alternative materials are urgent for orthopaedic surgeon. Here, we evaluated osteoblast-oriented differentiation of rabbit BMSCs by co-culturing with composite scaffolds constructed using silicon-substituted-CaP-fine particulate bone powder-alginate. Using CCk8-kit, biocompatibility was evaluated by testing BMSCs proliferation; morphology and survival of osteoblasts within scaffolds were observed using EM and HE staining; growth factors and related genes were detected using RT-PCR. HE staining showed spindle-shaped BMSCs after the 3rd passage; EM data showed that uneven surface and longitudinal section were observed with scattered distribution of 5-100 mm interspaces, which leave enough space for BMSCs adhesion and growth. Interestingly, at 14-day culture with HE staining, osteocytes within the scaffolds grew well with regular shape and integrate structure. RT-PCR results showed that expression levels of BMP2, TGF-b and COL-I, ALP, OPN were increased significantly and time-dependently. Collectively, all mentioned effects were more obvious in co-culture BMSCs with scaffolds than those with other components. Immunohistochemistry showed that positive OPN expression was detected at 7-day co-culturing BMSCs with scaffold, rather than other situations. These results suggest that composite scaffolds constructed with Si-CaP-fine particulate bone powder-alginate have a certain degree of biocompatibility and bioactivity to promote osteoblast-oriented BMSCs differentiation.

Expression of microRNA‑21 in osteoporotic patients and its involvement in the regulation of osteogenic differentiation

“…Studies have shown that bone marrow mesenchymal stem cells (BMSCs), as the main source of osteoblasts in humans, have multi-directional differentiation potential and can differentiate into osteoblasts, chondrocytes and adipocytes under certain conditions. Therefore, BMSCs play a very important role in the treatment of OP (7,8).…”

A novel tissue-engineered bone graft composed of silicon-substituted calcium phosphate, autogenous fine particulate bone powder and BMSCs promotes posterolateral spinal fusion in rabbits

“…We successfully synthesized the Si-CaP by an aqueous precipitation method in our previous study [ 21 ]. This composite possessed a silicon content of 0.8 ​wt%, with a total porosity of 75% and pore size of 150–300 ​μm.…”

“…Soft tissue such as connective tissue and cartilage was removed, and the bone was placed in 0.9% physiological saline. It was then ground with a standard bone mill on a fine setting in normal saline until it reached a particulate size of 300–500 ​μm, and centrifuged to obtain the AFPBP for further use [ 21 ].…”

“…The rapid resorption of AFPBP could release many bone growth factors, such as BMP-2, TGF-β1, ALP and collagen I, at an early stage of bone repair and reduce osteocytic creeping and substitution [ 20 ]. These factors could promote the differentiation of BMSCs into osteoblasts [ 21 ]. However, since such particles of the loose bone structure are easily lost, are difficult to mold, and have other shortcomings, the applications are limited.…”

“…They can not only differentiate into osteoblasts and exert osteogenic functions but also have advantages of stable growth, rapid proliferation, a high survival rate after inoculation, and easy and less invasive acquisition methods [ 22 ]. Thus, in our previous study, we constructed a novel tissue-engineered bone graft composed of Si-CaP, AFPBP, and BMSCs, which exerted good degradation performance, mechanical strength, and biological activity in vitro [ 21 , 23 ]. The scaffold could also induce BMSCs differentiation into osteoblasts and exerted no adverse effects on cell proliferation [ 23 ].…”