ObjectiveTo analyze the expression profile changes of osteogenic-related genes during spontaneous calcification of rat bone marrow mesenchymal stem cells (BMSCs). MethodsBMSCs were isolated from 3-day-old healthy Sprague Dawley rats;cells at the 4th generation were used to establish the spontaneous calcification model in vitro. Spontaneous calcification process was recorded by inverted phase contrast microscope observation and alizarin red staining after 7 and 14 days of culture. For gene microarray analysis, cell samples were collected at 0, 7, and 14 days after culture; the differentially expressed genes were analyzed by bioinformatics methods and validated by real-time quantitative PCR (RT-qPCR) assay. ResultsRat BMSCs calcified spontaneously in vitro. When cultured for 7 days, the cells began to aggregate and were weakly positive for alizarin red staining. After 14 days of culture, obvious cellular aggregation and typical mineralized nodules were observed, the mineralized nodules were brightly positive for alizarin red staining. A total of 576 gene probe-sets expressed differentially during spontaneous calcification, corresponding 378 rat genes. Among them, 359 gene probe-sets expressed differentially between at 0 and 7 days, while only 13 gene probe-sets expressed differentially between at 7 and 14 days. The 378 differentially expressed genes were divided into 6 modes according to their expression profiles. Moreover, according to their biological functions, differentially expressed genes related to bone cell biology could be classified into 7 major groups:angiogenesis, apoptosis, bone-related genes, cell cycle, development, cell communication, and signal pathways related to osteogenic differentiation. In cell cycle group, 12 down-regulated genes were linked with each other functionally. Matrix metalloproteinase 13 (Mmp13), secreted phosphoprotein 1 (Spp1), Cxcl12, Mmp2, Mmp3, Apoe, and Itga7 had more functional connections with other genes. The results of genes Spp1, Mgp, Mmp13, Wnt inhibitory factor 1, Cxcl12, and cyclin A2 by RT-qPCR were consistent with that of gene microarray. ConclusionThe first 7 days after rat BMSCs were seeded are a key phase determining the fate of spontaneous calcification. Multiple genes related with cell communication, bone-related genes, cell cycle, transforming growth factor-β signaling pathway, mitogen-activated protein kinase signaling pathway, and Wnt signaling pathway are involved during spontaneous calcification.
ObjectiveTo investigate the effectiveness of human placental decidua basalis derived mesenchymal stem cells (PDB-MSCs) in repairing full-thickness skin defect of nude mice. MethodsHuman placenta samples were obtained from healthy donor mothers with written informed consent. PDB-MSCs were isolated through enzymic digestion and density gradient centrifugation; the 4th passage cells were identified by cellular morphology, cell adipogenic and osteogenic differentiation, and phenotype evaluation. Forty-two 4-5-week-old BALB/c female nude mice were randomly divided into experimental group (n=21) and control group (n=21). The 4th passage PDB-MSCs solution (200 μL, 5×106/mL) was injected into the mice of experimental group via caudal vein; the mice of control group were given equal volume of PBS. The full-thickness skin defect model of 1.5 cm×1.5 cm in size was made after 3 days. The wound healing was observed generally at 1, 2, 4, 7, 14, 18, 21, 25, and 30 days after operation, and the wound healing rate was calculated after wound decrustation. HE staining was used to observe the wound repair at 1, 7, 14, 21, and 31 days; immunofluorescent staining was used for cellular localization at 7, 14, and 31 days after operation. ResultsCells isolated from human placenta were MSCs which had multipotential differentiation ability and expressed MSCs phenotype. Animals survived to the end of the experiment. The general observation showed that the experimental group had a faster skin repairing speed than the control group; the time for decrustation was 12-14 days in experimental group and was 14-17 days after operation in the control group. The wound healing rate of experimental group was significantly higher than that of control group at 14, 18, and 21 days (t=4.001, P=0.016; t=3.380, P=0.028; t=3.888, P=0.018), but no significance was found at 25 and 30 days (t=1.565, P=0.193; t=1.000, P=0.423). HE staining showed lower inflammatory reaction, and better regeneration of the whole skin and glands with time in the experimental group. The immunofluorescent staining was positive in skin defect area of experimental group at different time points which displayed that human PDB-MSCs existed. ConclusionThrough enzymic digestion and density gradient centrifugation, PDB-MSCs can be obtained. Pre-stored PDB-MSCs can mobilize to the defect area and participate in repair of nude mice skin.