BACKGROUND: Polylactic acid copolymer bone scaffold has excellent biodegradability, and it is easy to be shaped and can promote the formation and growth of bone tissue and blood vessel.OBJECTIVE: To observe the effects of adipose-derived stem cells(ADSCs)/poly(lactic-co-glycolic acid) (PLGA) complex on the biomechanical properties after fracture healing in osteoporotic bone.METHODS: Sixty Sprague-Dawley rats were randomly divided into four groups: blank control group received no treatment; the bilateral tibial fracture model was made after 3 months of bilateral ovarian resection in model group; the bilateral tibial fracture model was made and ADSCs were implanted into the bone after 3 months of bilateral ovarian resection in cell therapy group; the bilateral tibial fracture model was made and the PLGA/ADSCs complex was implanted after 3 months of bilateral ovarian resection in combined treatment group.The bone mineral density, callus thickness, biomechanical parameters and the microstructure of the trabecular bone were detected.RESULTS AND CONCLUSION: (1) The bone density: The bone density of the model group was significantly lower than that of the blank control group (P < 0.05); the bone mineral density of the cell therapy group and the combined treatment group was higher than that of the model group (P < 0.05), but lower than that of the control group (P < 0.05); and the bone mineral density of the combination treatment group was higher than that of the cell therapy group (P < 0.05). (2)Thickness of the callus: The thickness of the callus in the cell therapy group and combined treatment group was higher than that of the model group and blank control group (P < 0.05); moreover, the thickness of the callus in the combined treatment group was higher than that of the cell therapy group (P < 0.05). (3) Biomechanical test: The failure load, stress and shear strength, elastic modulus were decreased in the model group compared with the blank control group (P < 0.05), while the shear strain increased (P < 0.05). Compared with the model group, the failure load, ultimate stress, shear strength, elastic modulus were increased in the cell therapy group and combined treatment group (P < 0.05), and the shear strain was decreased (P < 0.05). Moreover, the combined treatment group showed more changes in these biomechanical parameters (P < 0.05). (4) The trabecular bone microstructure: The model group presented with trabecular derangement, spacing increases, and even fracture and lacuna. After ADSCs or ADSCs/PLGA transplantation,the trabecular bones increased in number, thickness, and spacing, and the number of lacunae reduced. In conclusion,ADSCs combined with PLGA in the treatment of osteoporotic fracture can significantly improve the biomechanical parameters of bone tissue after healing.

BACKGROUND: SSh as a Hedgehog signal protein can promote bone development, growth and remodeling.OBJECTIVE: To investigate the effect of bone marrow mesenchymal stem cells (BMSCs) combined with Shh modified nano-hydroxyapatite/collagen (nHAC) in the repair of femoral defects in rats.METHODS: Forty-eight Sprague-Dawley rats were randomly divided into four groups, and the model of femoral defects was established in these rats. At 14 days after modeling, experimental group was implanted with the BMSCs/Shh modified nHAC, scaffold group was implanted with simple nHAC, cell scaffold group was implanted with BMSCs/nHAC,and blank control group was without any implantation. At 3, 6, 9, 12 weeks after repair, X-ray examination, bone density measurement and bone biopsy in bone defect area were performed.RESULTS AND CONCLUSION: (1) X-ray examination: The Lane-Sandhu X-ray score and bone mineral density value in the experimental group at different time points after operation were significantly higher than those in the other three groups (P < 0.05). (2) Hematoxylin-eosin staining: 12 weeks after repair, a small amount of bone tissues but no bone marrow formed in the scaffold group; a small amount of bone tissues with absence of bone marrow formed in the cell scaffold group, and the residual scaffold was visible; in the experimental group, the scaffold was completely absorbed,and mature bone and medullary cavity formed with presence of bone marrow. (3) Scanning electron microscope observation: 12 weeks after repair, irregular arrangement of bone fibers and a large number of bone fossae were observed in the scaffold group; the cell scaffold group showed a large number of osteoblasts, but bone fibers still arranged irregularly; in the presence of the Haversian system, a large number of regularly arranged bone trabeculae were detective in the experimental group. These results elucidate that the Shh modified nHAC/BMSCs complex can promote the repair of bone defects.

ObjectiveTo isolate and culture human adipose derived mesenchynal stem cells (hADSCs) and study the potential of hADSCs to differentiate into hepatocyte-like cells. MethodsTo ensure the removal of contaminating hematopoietic cells, hADSCs were selected based on plastic adherence. Cell surface antigen was confirmed by flow cytometry; ultramicrostructure was detected by transmission electron microscopy; adipogenic and osteogenic differentiation of hADSCs was analyzed by oil Red O staining and yon Kossa staining. hADSCs were exposed to differentiation medium containing EGF,FGF,OSM, HGF,TSA in vitro. 10% CCl4 (100 μ1/20 g body weight )was injected into immune-deficient BALB/c-nu mice and hADSCs (5 × 105 cells) were simultaneously administrated from the tail vein. Blood samples were collected and concentration of aminotransferase and direct bilirubin were detected. Administration without hADSCs was used as a control. One month later, we sacrificed the mice and liver sections were examined by histochemical immunofluorescence with human ALB specific antibodies. ResultshADSCs exhibited fibroblast-like morphology, and expressed CD73, CD90,CD105, and were lacking of CD34 and CD45. Adipogenic and osteogenic differentiation showed that hADSCs have the capacity of multidifferentiation. The differentiated cells showed hepatocyte-like cell morphologies and hepatocyte-specific markers including albumin (alb) and α-fetoprotein (AFP). The bioactivity assays revealed that these hepatocyte-like cells could uptake low-density lipoprotein (LDL).Histochemical immunofluorescence showed that hADSCs were incorporated into injured livers. Some human alb-positive cells were found in liver sections after implantation of undifferentiated hADSCs. Transaminase activity in the experimental group was lower than in the control group. Conclution hADSCs can differentiated into functional hepatocyte-like cells and can relieve CCl4 induced BALB/c-nu acute liver injury.

Objective Tocomparetherejectionoflivertransplantationindifferentstrains combinationofrats.Methods Fourtransplantationmodelsofvariousstraincombinationswereestablished including the control group SD (donor)to SD (recipient)(group A)and the experimental groups Wistar to SD (group B),Lewis to BN (group C)and DA to Lewis (group D). Orthotopic liver transplantation model of rats were constructed by Kamada's two cuff technique. And serum hepatic functions in 4 groups of recipient rats at 10th day after liver transplantation were compared,which was including alanine aminotransferase (ALT), total bilirubin (TB)and albumin (Alb). Meanwhile the serum levels of interleukin (IL)-2 and IL-10, rejection activity index (RAI)at 10th day after liver transplantation and the average survival time of recipient ratswereinvestigated.Results ComparedwithgroupAandB,theserumlevelsofALTandTBofgroupC and D increased obviously,while Alb decreased significantly. Compared with group C,TB of group D increased obviously,while Alb decreased remarkably. All of the differences were statistically significant (all in P <0.05). Compared with group A,the serum levels of IL-2 and IL-10 in group B,C and D all elevated significantly,and IL-2/IL-10 in group C and D increased remarkably too (all in P<0.05 ). Compared with group B,IL-2 in group C and D increased significantly,and IL- 2 /IL-10 in group D also elevated significantly. Compared with group C,both IL-2 and IL-2/IL-10 in group D increased significantly. All the differences were statistically significant (all in P<0.05 ). Hepatic histopathological examination showed that obvious rejection did not occur in the recipient rats of group A,which rejection activity index (RAI)was scored 1.8 ±0.7. The RAI score of Group B,C and D were 3.1 ±1.3,6.9 ±0.8 and 8.8 ±0.5,which belonged to mild or vague rejection,moderate to severe rejection and severe rejection respectively. All the RAI scores comparison among and between each group had statistical differences (all in P<0.05 ). The average survival time of recipient rats in group A,B,C and D were (119.3 ±1.9)d,(116.9 ±8.3)d,(53.4 ±6.1)d and (12.1 ±2.4)d respectively. There was no statistically significant difference between group A and B,while the comparisonbetweenanyothergroupwasstatisticallysignificant(allinP<0.05).Conclusions Infour different rats strains combination,the rejection is most serious in the model of DA (donor) to Lewis (recipient),moderate in Lewis to BN,mildest and near to tolerance in Wistar to SD.