OBJECTIVE To investigate the feasibility of osteoid callus allograft as a kind of bone healing promoting materials. METHODS The osteoid callus was obtained at one week after bilateral femoral fracture of a SD rat, then was kept at -196 C for 2 weeks. The bone defect model which bone repair was in intra-membranous osteogenesis was made at bilateral tibial shaft in 5 rats, and filled with the osteoid callus in the left defect area, the right side was filled with allogenous cancellous as control group. The specimen were processed with undecalcified technique and the sections were staining with light blue and sofranin T. RESULTS After 2 weeks, there were cartilage and bone formation in the defect area of osteoid callus graft group(3/4), medullary cavity formation in bone tissue with cartilage arround it, fibrous tissues between new bone and host bone. While there were no cartilage or bone formation in the control group. CONCLUSION The allograft osteoid callus is not absorbed by immunological rejection, but changed into bone tissue through endochondral osteogenesis. It is inspiring to develop osteoid callus allograft as a kind of material for bone healing.
ObjectiveTo explore the effects of concentrated growth factor (CGF) combined with mineralized collagen (MC) materials on the adhesion, proliferation, and differentiation of bone marrow mesenchymal stem cells (BMSCs) and their osteogenic effects in vivo, and to provide a theoretical basis for the combined application of CGF and MC materials in bone defect regeneration and repair.MethodsCGF was prepared from venous blood of healthy volunteers, and then CGF extracts (CGFe) were prepared. In vitro experiment: human BMSCs (hBMSCs) were divided into 4 groups. Groups A, B, and C were cultured with α-MEM medium [containing 10% fetal bovine serum (FBS) and 1% double antibody] containing 2%, 5%, and 10%CGFe, respectively; group D was cultured with α-MEM medium (containing 10%FBS and 1% double antibody) without CGFe. Scanning electron microscopy was used to observe the effect of CGFe on cell adhesion. Cell counting kit 8 (CCK-8) was used to detect the effect of CGFe on cell proliferation. After osteogenic induction, alkaline phosphatase (ALP) activity was detected and Western blot was performed to detect osteopontin (OPN) expression. In vivo experiment: Eighteen New Zealand big-eared rabbits were used to prepare circular bone defect models on the left and right mandibles, and implant CGF gel (prepared from autologous venous blood)+MC material (volume ratio 1∶1, experimental group) and simple MC material (control group), respectively. At 4, 8, and 12 weeks after operation, 6 rabbits were sacrificed respectively to obtain materials, and Micro-CT scanning was performed to observe the formation of new bone and material degradation in vivo.ResultsIn vitro experiments: Scanning electron microscopy showed that the cells of groups A, B, and C spread better on MC materials than group D, with more pseudopodia. CCK-8 method showed that different concentrations of CGFe could promote cell proliferation, and the absorbance (A) value of cells cultured for 2, 3, 5, and 7 days was in the order of group C>group B>group A>group D, the differences were significant (P<0.05). ALP activity test showed that its activity was proportional to the osteogenic induction time and CGFe concentration (P<0.05). Western blot analysis of osteogenic induction culture for 14 days showed that the relative expression of OPN protein in groups A, B, and C was significantly higher than that in group D, and the higher the CGFe concentration, the higher the relative expression of OPN protein (P<0.05). In vivo experiment: Micro-CT observation showed that the new bone formation and material degradation of the experimental group were better than those of the control group at 4, 8, and 12 weeks after operation. Quantitative detection showed that the volume of new bone volume, new bone volume fraction, trabeculae number, and trabecular thickness of the experimental group were significantly higher than those of the control group at each time point, the residual material volume, residual material volume fraction, and trabecular separation were significantly lower than those of the control group, all showing significant differences (P<0.05).ConclusionCGF can effectively promote the adhesion, proliferation, and osteogenic differentiation of BMSCs on MC materials, and 10%CGFe has the most significant effect. The combined application of CGF and MC material can significantly promote bone formation in vivo.
ObjectivesTo systematically review the proportion of Tregs in peripheral blood of patients with ankylosing spondylitis (AS) and its relationship with Treg's diffrent phenotypes.MethodsPubMed, EMbase, The Cochrane Library, CNKI, WanFang Data and VIP databases were electronically searched to collect case-control studies on peripheral Tregs of AS patients from inception to November 31st, 2018. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was performed by using Stata 12.0 software.ResultsA total of 61 case-control studies involving 2 466 AS patients and 1 879 controls were included. The results of meta-analysis showed that: the proportion of peripheral Tregs of patients with AS was significantly lower than that of the normal control (SMD=−0.905, 95%CI −1.294 to −0.517, P<0.000 1), and the proportion of Tregs in the disease-active group was significantly lower than that in disease-inactive group (SMD=−0.928, 95%CI −1.431 to −0.425, P<0.000 1). The proportion of CD4+CD25+FOXP3+Tregs and CD4+CD25+CD127low/−Tregs were lower in AS patients than that in control subjects (SMD=−2.547, 95%CI −3.521 to −1.573, P<0.000 1; SMD=−0.709, 95% CI −1.056 to −0.362, P<0.000 1). The proportion of Tregs defined by CD4+CD25low/−FOXP3+ was higher in AS patients (SMD=0.683, 95%CI 0.161 to 1.206, P=0.01). There was no significant difference betweew other phenotypes of Tregs groups.roups.ConclusionsThe reduction of Tregs may be one of the important reasons for the occurrence and development of AS, which may provide a new approach for the diagnosis and treatment of AS.