Comparing the chondrogenic potential in vivo of autogeneic mesenchymal stem cells derived from different tissues.

OBJECTIVE: to compare the chondrogenic ability of mesenchymal stem cells (MSCs) derived from different tissues in rabbits' full-thickness articular cartilage defects. METHODS: sixty New Zealand white rabbits of ordinary grade with a body weight of 2.5 approximately 3.5kg were selected for this study. Six were sacrificed for preparation of deminerized bone matrix (DBM) as scaffold. Fifty-four were used for cartilage defects model. Full-thickness cartilage defect of knee joint was created on trochlear groove at two sides of the femur with a diameter of 4 mm and thickness of 3 mm. All 54 rabbits were randomly divided into 6 groups and treated by autogeneic MSCs isolated from bone marrow, periosteum, synovium, adipose tissue and muscle, respectively. The 6th group was a control group with nothing plugged into the defects. Every three rabbits were killed at three time points, which were 4, 8, and 12 weeks after the operation in each group. The reparative tissue samples were evaluated grossly, histologically, immunohistochemically, and graded according to gross and histological scales 12 weeks postoperatively. We input the scores into SPSS 11.5 software and the analysis of variance (one-way-ANOVA) and student-newman-keuls (SNK-q) test were used to process statistical analysis and find out if the differences between each group had statistical significance. RESULTS: fifty-four rabbits are included in the final analysis. The defects are all repaired by hyaline-like tissue except the control group. The bone-marrow-MSCs produced much more cartilage matrix than that of other groups. Gross and histological grading scale indicates that the defects repaired by MSCs isolated from bone marrow are superior to that repaired by MSCs isolated from periosteum, synovium, adipose tissue, and muscle (p < 0.05). In adipose-MSCs and muscle-MSCs group, some defects are even repaired by fibrous tissue. CONCLUSION: bone-marrow-MSCs have greater in vivo chondrogenic potential than periosteum-, synovium-, adipose- and muscle-MSCs.

In vitro and in vivo biocompatibility investigation of diamond-like carbon coated nickel-titanium shape memory alloy.

OBJECTIVE: To investigate the biocompatibility of diamond-like carbon (DLC) coated nickel-titanium shape memory alloy (NiTi SMA) in vitro and in vivo. METHODS: The in vitro study was carried out by co-culturing the DLC coated and uncoated NiTi SMA with bone marrow mesenchymal stem cells (MSCs), respectively, and the in vivo study was carried out by fixing the rabbits' femoral fracture model by DLC coated and uncoated NiTi SMA embracing fixator for 4 weeks, respectively. The concentration of the cells, alkaline phosphatase (AKP), and nickel ion in culture media were detected, respectively, at the first to fifth day after co-culturing. The inorganic substance, osteocalcin, alkaline phosphatase (ALP), and tumor necrosis factor (TNF) in callus surrounding fracture and the Ni(+) in muscles surrounding fracture site, liver and brain were detected 4 weeks postoperatively. RESULTS: The in vitro study showed that the proliferation of MSCs and the expression of AKP in the DLC-coated group were higher than the uncoated group (P < 0.05), while the uncoated group released more Ni(2+) into the culture media than that in the coated group (P < 0.05). The in vivo study revealed that the inorganic substance and AKP, osteocalcin, and TNF expression were significantly higher in the DLC coated NiTi SMA embracing fixator than that in the uncoated group (P < 0.05). Ni(2+) in liver, brain, and muscles surrounding the fracture were significantly lower in the DLC coated groups than that in the uncoated group (P < 0.05). CONCLUSION: Nickel-titanium shape memory alloy coated by diamond-like carbon appears to have better biocompatibility in vitro and in vivo compared to the uncoated one.