ObjectiveTo investigate the effect of graphene oxide (GO)-carboxymethyl chitosan (CMC) hydrogel loaded with interleukin 4 (IL-4) and bone morphogenetic protein 2 (BMP-2) on macrophages M2 type differentiation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).MethodsGO solution was mixed with CMC, then the phosphate buffered saline (PBS), IL-4, BMP-2, or IL-4+BMP-2 were added to prepare different GO-CMC hydrogel scaffolds with or without different cytokines under crosslinking agents. The characteristics of pure GO-CMC hydrogel were characterized by gross observation, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR), and the CMC hydrogel was used as control. The sustained release of GO-CMC hydrogels with different cytokines was also tested. Macrophages were isolated and cultured from female Sprague Dawley rats aged 4-5 weeks, and then cultured with GO-CMC hydrogels with and without different cytokines, respectively. CD206 immunofluorescence staining was used to detect the differentiation of macrophages after 24 hours. The 3rd generation of rats BMSCs were cultured with GO-CMC hydrogels with and without different cytokines respectively for osteogenic induction. The early osteogenesis was observed by alkaline phosphatase (ALP) staining after 10 days, and the late osteogenesis was observed by alizarin red staining after 21 days.ResultsGenerally, GO-CMC hydrogel was brown and translucent. SEM showed that the pore diameter and wall thickness of GO-CMC hydrogel were similar to that of CMC hydrogel, but the inner wall roughness increased. FTIR test showed that CMC polymerized to form hydrogel. In vitro, the sustained release experiments showed that the properties of GO-CMC hydrogels loaded with different cytokines were similar. CD206 immunofluorescence detection showed that GO-CMC hydrogels could induce macrophages differentiation into M2-type. ALP and alizarin red staining showed that GO-CMC hydrogels could induce BMSCs osteogenic differentiation, in which GO-CMC hydrogel loaded with IL-4+BMP-2 showed the most significant effect (P<0.05).ConclusionThe GO-CMC hydrogel loaded with IL-4 and BMP-2 can induce macrophages differentiation into M2-type and enhance the ability of BMSCs with osteogenic differentiation in vitro, which provide a new strategy for bone defect repair and immune regulation.
ObjectiveTo separate peripheral blood mesenchymal stem cells (PBMSC) and peripheral blood endothelial progenitor cells (PBEPC) from peripheral blood, and investigate the biological characteristics of composite cell sheets of PBMSC and PBEPC.MethodsThe peripheral blood of healthy adult New Zealand white rabbits was extracted and PBMSC and PBEPC were separated by density gradient centrifugation. Morphological observation and identification of PBMSC and PBEPC were performed. The 3rd generation of PBMSC and PBEPC were used to construct a composite cell sheet at a ratio of 1∶1, and the 3rd generation of PBMSC was used to construct a single cell sheet as control. The distributions of cells in two kinds of cell sheets were observed by HE staining. In addition, the expression of alkaline phosphatase (ALP), osteocalcin (OCN), and vascular endothelial growth factor (VEGF) in the supernatants of cell sheets were observed by ELISA at 1, 5, and 10 days after osteogenic induction.ResultsThe morphology of PBMSC was spindle-shaped or polygonal, and PBMSC had good abilities of osteogenic and adipogenic differentiation. The morphology of PBEPC was paved stone-like, and the tube-forming test of PBEPC was positive. Two kinds of cell sheets were white translucent. The results of HE staining showed that the composite cell sheet had more cell layers and higher cell density than the single cell sheet. The expressions of ALP, OCN, and VEGF in the supernatant of the two groups of cell sheets increased with the time of induction. The expression of OCN in the group of composite cell sheet was significantly higher than that in the group of single cell sheet on the 5th and 10th day, ALP on the 10th day was significantly higher than that in the group of single cell sheet, VEGF expression on the 1st, 5th, and 10th day was significantly higher than that in the group of single cell sheet, all showing significant differences (P<0.05), and there was no significant difference between the two groups at other time points (P>0.05).ConclusionPBMSC have stable differentiation ability, and they have good application prospects because of their minimally invasive access. Composite cell membranes constructed by co-culture of two kinds of cells and induction of membrane formation provides a new idea and exploration for tissue defect repair.