OBJECTIVE: To study the effect of simvastatin on the expression of bone morphogenetic protein-2 (BMP-2) and alkaline phosphates (ALP) activity in the primary cultured bone marrow stromal cells, and to elucidate the mechanism of the anabolic osteogenetic effect of simvastatin. METHODS: Bone marrow stromal cells in femur and tibia of adult mouse were cultured in vitro. after treated with different concentrations of simvastatin (0, 0.1, 0.2, 0.5 and 1.0 mumol/L) or recombinant human BMP-2 for 72 hours, ALP activity of bone marrow stromal cells was determined. BMP-2 expression of bone marrow stromal cells was analyzed by using immunocytochemistry and Western blotting. RESULTS: After treated with simvastatin for 72 hours, BMP-2 expression increased, while little BMP-2 expression could be observed in the control group. ALP activity also increased in a dose-dependent manner; t-test showed that ALP activity in the group which concentrations of simvastatin were 0.5 mumol/L (t = 2.35, P = 0.041), 1.0 mumol/L (t = 2.348, P = 0.041) had significant difference when compared with control group. CONCLUSION: Simvastatin lead to high expression of BMP-2 in bone marrow stromal cells, via the increased auto- or para-crine of BMP-2, and ALP activity increased. These may be parts of the mechanism on the anabolic osteogenetic effect of simvastatin.
The osteogenc potential of bone marrow has been proved by experiment. To investigate more in details, bone marrow was obtained from the trochanteric region of femur of NewZealand rabbit in 4 to 8 weeks old. After being cultured in vitro for one week, the hematopoietic component of the bone marrow had disappeared, thus the stromal cells were obtained. Then the stromal cells were subcultured in cultural fluid containing dexamethasone (10-8 mol/L) and natrium glycerophosphate (10mmol/L). Under the phasecontrast microscope, it was found that being cultured for 15 days. The stromal cells were lined up in one layer and late the secretion activity was increased and gradually transformed into multilayer structure and was congregated into diffused opaque clusters in twenty days. During culture, the cells were examined by tetracycline fluorescence label, histochemistry stains, transmission electron microscopy, scanning electron microscopy and energy dispersive X-ray microanalysis. The results showed that the morphological and biological characteristics of the cultured stromal cells derived from the bone marrow were similiar to those of osteoblasts and could synthesized mineralized new bone tissue in vitro.
Objective To elucidate whether glucose transporters-4 （GLUT-4） takes part in glucose uptake of mesenchymal stem cells （MSCs） and whether Akt gene improves translocation and expression of GLUT-4 in MSCs under hypoxic environment ex vivo. Methods MSCs, transfected by Akt gene and no, were cultured with normoxia (5% CO2) or hypoxia (94%N2, 1%O2 and 5% CO2) at 37 ℃ for 8 h. Glucose uptake was assayed by using radiation isotope 2-［3H］-deoxy-Dglucose (3H-G) and the expression of GLUT-4 protein and mRNA was assayed by immunocytochemistry, Western blot and RT-PCR, respectively. Results ①3 H-G intake of MSCs was significantly increased in hypoxiatransfection group than that in hypoxia-non-transfection 〔（1.39±0.13） fold, P＜0.05〕, but which was lower than that in normoxia-non-transfection group, P＜0.05. ②GLUT-4 was expressed by MSCs under any conditions. Compared with normoxia-non-transfection group, hypoxia decreased the expressions of GLUT-4 mRNA and protein significantly (P＜0.05). ③Compared with hypoxianontransfection group, the expression of GLUT-4 〔mRNA（1.756±0.152） fold, total protein in cell （1.653±0.312） fold, protein in plasma membrane （2.041±0.258） fold〕 was increased in hypoxia-transfection group significantly (P＜0.05), but which was lower than that in normoxianontransfection group (P＜0.05). ④There was significantly positive relation between 3H-G intake and GLUT-4 protein expression in plasma membrane (r=0.415, P=0.001).Conclusion GLUT-4 may take part in glucose uptake of MSCs, and the capability of Akt gene to improve MSCs anti-hypoxia may be finished by its role in increasing the expression and translocation of GLUT-4.
Abstract： Objective To investigate the effects of hepatocyte growth factor（HGF）gene transfected bone marrow mesenchymal stem cells （MSCs）transplantation in pigs with chronic ischemic heart disease. Methods MSCs were isolated from pig bone marrow by density gradient centrifugation and adherent cell culture, purified, and determined by cellsurface antigens（CD34, CD44, CD71, Ⅷ factor and desmin）. MSCs were transfected by adenovirus expressing hepatocyte growth factor（AdHGF）, and the influence of HGF on the biological characteristics of MSCs was tested. The pig model of chronic myocardial ischemia was established by placing Ameroid ring inside the left circumflex coronary artery via leftthoracotomy. A total of 40 pigs were randomly divided into 5 groups （n=8） and were injected 5×106/ml MSCs＋ 4×109 pfu 200 μl AdHGF （MSCs＋ AdHGF group）, 4×109 pfu 200 μl AdHGF （AdHGF group）, 5×106/ml MSCs 200 μl（MSCs group），4×109 pfu 200 μl AdNull （AdNull group）and 1 ml saline（control group） into the ischemic myocardiumrespectively. Echocardiogram, digital subtraction angiography （DSA） of coronary artery, single photon emission computed tomography（SPECT） myocardial perfusion imaging and cardiomyocyte apoptosis were examined after 4 weeks. Results Positive CD44 and CD71 and negative CD34, Ⅷ factorand desmin were detected in MSCs by flow cytometer. HGF had a b influence on stimulating the proliferation and differentiation of MSCs. Echocardiogram examination showed that left ventricular end-diastolic volume（LVEDV），left ventricular ejection fraction（LVEF），fractional shortening（FS）of MSCs＋ AdHGF group were significantly increased after treatment （P＜ 0.05）. DSA detection showed that ischemic neovascularization of MSCs＋ AdHGF group was significantly higher than those of AdHGF group and MSCs group （P＜ 0.05）. SPECT showed that the left ventricular myocardium of MSCs＋ AdHGF group appeared thickened,myocardial perfusion was significantly improved and the myocardial motion was significantly increased （P＜ 0.05）. Vascular density of MSCs＋ AdHGF group was significantly higher than those of AdHGF group and MSCs group by HE stain of myocardium ［（39.4±1.2）/ HPF vs. （36.5±1.4）/ HPF and（34.5±1.7）/ HPF，P＜ 0.05］. Cardiomyocyte apoptosis rate of MSCs＋ AdHGF group was significantly lower than those of AdHGF group and MSCs group by TUNEL stain （P＜ 0.05）. Conclusion Combination transplantation can promote the angiogenesis of chronic ischemic myocardium, inhibit cardiomyocyte apoptosis and improve heart function in pigs with chronic ischemic heart disease. The effect of HGF gene transfected MSCs transplantation is better than that of MSCs or HGF transplantation alone.
Objective To investigate the role of bone marrow-derived cells (BMC) plays in choroidal neovascularization (CNV).Methods Green fluorescent protein (GFP) chimeric mice were built by transplanting BMC from GFP transgenic mice to adult wild type C57BL/6J mice. Retinal laser photocoagulation was used to induce CNV in the chimeric mice (treated group) and adult wild type mice (control group). Four weeks later, choroidal flatmount was prepared to detect GFP positive BMC expression in the CNV lesions, and immunofluorescence stain was used to determine the expression of vascular endothelia growth factor (VEGF) and basic fibroblast cell growth factor (bFGF).Results Twenty-nine days after photocoagulation lots of GFPpositive BMC presented in the CNV area, which accounted approximate 16.22% of the total CNV area. Some BMC in the CNV area expressed VEGF and bFGF. Conclusions BMC may play an important role in CNV by forming new vessles and secreting angiogenic factors.
ObjectiveTo observe transforming growth factor β3 (TGF-β3) gene expression and the chondrogenesis of bone marrow mesenchymal stem cells (BMSCs) after TGF-β3 gene is transfected into BMSCs of Diannan small-ear pig. MethodsRecombinant adenovirus 5 (rAd5) was extracted as gene vector and packed into recombinant adenovirus rAd5-TGF-β3, double enzyme digestion and PCR identification were performed. BMSCs were isolated and cultured from bone marrow of 2-month-old Diannan small-ear pigs (weighing, 12-15 kg), and the 2nd generation of BMSCs were harvested for experiments. The experiments were divided into 3 groups. BMSCs were transfected with rAd5-TGF-β3 as experimental group and with empty vector as control group, and non-transfected BMSCs were used as blank control group. The transfection efficiency of exogenous gene was identified by flow cytometry, TGF-β3 protein expression by immunofluorescence and Western blot. The cell morphology of experimental group was observed by inverted phase contrast microscope, and the expression of collagen type II in each group was detected by Western blot. ResultsThe rAd5-TGF-β3 recombinant adenovirus was successfully constructed and transfected into BMSCs. Green fluorescence was observed by immunofluorescence microscope. Flow cytometry test showed the best transfection at 72 hours (transfection efficiency of 84.86%). Immunofluorescence staining showed that the expression of TGF-β3 protein was obvious at 72 hours; Western blot showed that there was a TGF-β3 positive band with a relative molecular mass of 30×103, while the control group and blank control group had no positive band. Obvious chondrogenic differentiation was observed in the experimental group after transfection in vitro, while the control group and blank control group had no obvious chondrogenic differentiation. Western blot showed that there was collagen type II positive band with a relative molecular mass of 130×103 at 21 days after culture, while the control group and blank control group had no positive band. ConclusionrAd5-TGF-β3 gene can be successfully transfected into BMSCs via adenovirus vectors, and stable expression of TGF-β3 protein can be observed, enhancing BMSCs differentiation into chondrocytes, which may provide an experimental basis for gene therapy of joint cartilage defects.
Abstract To examine the effects of porous tricalcium phosphate (TCP) combined with autogenous red bone marrow (BM) in therepar of bone defects, 21 cases of bone defects were implanted with the above prepared composite material, 17 cases had benign or low-grade malignant tumors and 4cases had old fractures. Serial X-ray films were taken after surgery. The results showed that new bone formation was seen between the interface of the implantand surrounding host bone after 6 weeks, and osseous union developed after 12 weeks. Evident osteogenesis in all patients was observed after a follow-up for 1～3 years. TCP-BM is both osteoconductive and osteoinductive. Its function was similar to the fresh autogenous cancellous bone graft and TCP-BM had the potencyof promoting the repair of osseous defect. It was suggested that TCP-BM might be an ideal material for treating bone defects.
ObjectiveTo investigate the effect of LOC103693069 on hypoxic apoptosis of bone marrow mesenchymal stem cells (BMSCs). Methods BMSCs from 1-week-old Sprague Dawley rat bone marrow were isolated, cultured, and passaged by the whole bone marrow adherent culture method. After identification of adipogenic, chondrogenic, and osteogenic differentiation, the 3rd generation cells were treated with hypoxia under 5%O2, 1%O2, and anaerobic conditions. After 48 hours, the cell viability, apoptosis, and apoptosis-related proteins [hypoxia inducible factor 1α (HIF-1α), Caspase-3, B cell lymphoma/leukemia 2 (Bcl-2)] expressions were detected, and normal BMSCs were used as controls. Based on the research results, the concentration group with the most obvious apoptosis was selected and used for subsequent experiments. After 48 hours of hypoxia treatment, BMSCs were taken and analyzed by gene chip and real-time fluorescence quantitative PCR (qRT-PCR) to screen the most significantly down-regulated gene and construct their high-expression, low-expression, and negative control lentiviruses; BMSCs were transfected with the different lentiviruses, respectively. After qRT-PCR detection confirmed that the transfection was successful, the BMSCs were treated with hypoxia for 48 hours to observe the cell viability and the expressions of apoptosis-related proteins. ResultsAfter cell viability, apoptosis, and apoptosis-related proteins were detected, cell apoptosis was the most significant under anaerobic conditions after 48 hours. The above indicators were significantly different from other groups (P<0.05), and this group was used for treatment conditions for subsequent experiments. Gene chip analysis showed that after 48 hours of hypoxia treatment, AC125847.1, LOC102547753, AABR07017208.2, and LOC103693069 were significantly down-regulated in BMSCs, and the expressions of LOC103693069 was the most significant down-regulation detected by qRT-PCR (P<0.05). It was selected to construct lentivirus and transfect BMSCs. Afterwards, qRT-PCR detection showed the successful transfection into the cells. After hypoxia treatment, the apoptosis rate and the expressions of apoptosis-related proteins of BMSCs overexpressed by the gene were significantly reduced (P<0.05). Conclusion LOC103693069 can relieve the hypoxic apoptosis of BMSCs.
ObjectiveTo investigate the feasibility of tissue engineered periosteum (TEP) constructed by porcine small intestinal submucosa (SIS) and bone marrow mesenchymal stem cells (BMSCs) of rabbit to repair the large irregular bone defects in allogenic rabbits. MethodsThe BMSCs were cultivated from the bone marrow of New Zealand white rabbits (aged, 2 weeks-1 month). SIS was fabricated by porcine proximal jejunum. The TEP constructed by SIS scaffold and BMSCs was prepared in vitro. Eighteen 6-month-old New Zealand white rabbits whose scapula was incompletely resected to establish one side large irregular bone defects (3 cm×3 cm) model. The bone defects were repaired with TEP (experimental group,n=9) and SIS (control group,n=9), respectively. At 8 weeks after operation, the rabbits were sacrificed, and the implants were harvested. The general condition of the rabbits was observed; X-ray radiography and score according to Lane-Sandhu criteria, and histological examination (HE staining and Masson staining) were performed. ResultsAfter operation, all animals had normal behavior and diet; the incision healed normally. The X-ray results showed new bone formation with normal bone density in the defect area of experimental group; but no bone formation was observed in control group. The X-ray score was 6.67±0.32 in experimental group and was 0.32±0.04 in control group, showing significant difference (t=19.871,P=0.001). The general observation of the specimens showed bone healing at both ends of the defect, and the defect was filled by new bone in experimental group; no new bone formed in the control group. The histological staining showed new bone tissue where there were a lot of new vessels and medullary cavity, and no macrophages or lymphocytes infiltration was observed in the defect area of experimental group; only some connective tissue was found in the control group. ConclusionTEP constructed by porcine SIS and BMSCs of rabbit can form new bone in allogenic rabbit and has the feasibility to repair the large irregular bone defects.
OBJECTIVE To investigate the ectopic osteogenesis of bone marrow stromal cells (MSC) induced by bone morphogenetic protein(BMP) in vitro and in vivo, providing the experimental evidence for making an artificial bone with its own capacity of bone formation. METHODS MSC were separated and cultured from bone marrow of Wistar rats, MSC were co-cultured with BMP in vitro (cultured in plate and diffuse chamber). Artificial coral hydroxyapatites (CHA) with MSC and BMP were implanted into dorsal muscles of Wistar rats, their bone formation were observed by morphological examination, histochemistry and immunohistochemistry. RESULTS Only cartilaginous matrix were produced by MSC in vitro (cultured in plate and diffuse chamber), and both cartilaginous and bone matrix production within the combined grafts were seen. The bone formation of experimental groups (CHA + BMP + MSC) was ber than that of control A(CHA + MSC) and control B(CHA). CONCLUSION It may be possible to produce an artificial bone with its own capacity of bone formation by combined graft (CHA + BMP + MSC). There may be multiple factors as well as BMP inducing bone formation both in the whole body and the location of the implantation. Further research on these factors will have the significance for making the ideal artificial bone.