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.
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.
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.
ObjectiveTo review the research progress of induced osteogenesis of bone marrow mesenchymal stem cells (BMSCs) transfected by double-gene. MethodsThe recent literature concerning the comparative research of induced osteogenesis of BMSCs transfected by double-gene was extensively reviewed. The characteristics of BMSCs, the advantage and effect of synergistic inductive osteogenesis, the application prospect and problems of BMSCs transfected by double-gene were summarized. ResultsThe effect of induced osteogenesis concerning BMSCs transfected by double-gene is far superior to single gene transfection and the activity of osteoblast is also significantly increased. The research used in bone tissue engineering experiment also obtain good effect. ConclusionInduced osteogenesis of BMSCs transfected by double-gene is able to make up for the lack of a single gene transfection and has great development prospects in the orthopaedic field.
Objective The bone marrow mesenchymal stem cells (BMSCs) have the capacity to differentiate into insul in-producing cells (IPCs) in vitro. However, low differentiation efficiency and poor maturity are the main obstacles. To investigate the feasibil ity of BMSCs differentiation into IPCs in diabetic pancreatic microenvironment of pigs. Methods BMSCs were isolated and purified from the bone marrow of a 4-week-old male pig. Fifteen female pigs (aged 8 to 10 weeks, weighing 8 to 10 kg) were randomly divided into 3 groups: normal control group (group A, n=5), diabetic control group (group B, n=5), and BMSCs transplanted group (group C, n=5). The pigs of groups B and C were treated by auris vein injections of styeptozocin and alloxan for 3 days to induce diabetes mell itus (DM) model, whose blood glucose level 2 days all greater than 17 mmol/L was successful DM model. A total of 1.1 mL of the 3rd passage BMSCs labeled with enhanced green fluorescent protein (EGFP), with cell density of 5 × 107/ mL, were injected into subcapsular pancreas of group C at multi ple points, normal saline at the same dosage into those of groups A and B. After 30 days of monitoring blood glucose, the histological analysis of islet number and size were done; the immunofluorescence staining was used to detect the protein expression of insul in in the new-formed islets. The EGFP+ cells were collected from the sections using laser-capture microdissection; RT-PCR was used to detect insulin mRNA and pancreatic and duodenal homeobox factor 1 (PDX1) mRNA expressions from EGFP+ cells, and the insul in and sexdetermining region of the Y chromosome (SRY) genes were detected by fluorescence in situ hybridization (FISH). Results The blood glucose level decreased significantly in group C when compared with that in group B from 18 days and gradually decreased with time (P lt; 0.05). The histological observation showed that the number of islets was increased significantly in group C when compared with that in group B (10.9 ± 2.2 vs. 4.6 ± 1.4, P lt; 0.05), and there was no significant difference when compared with that in group A (10.9 ± 2.2 vs.12.6 ± 2.6, P gt; 0.05). The size of new-formed islets in group C was significantly smaller than that in group A [(47.2 ± 19.6) μm vs. (119.6 ± 27.7) μm, P lt; 0.05]. The immunofluorescence staining showed that new-formed islets of group C expressed insulin protein. RT-PCR showed that the microdissected EGFP+ cells of group C expressed insulin mRNA and PDX-1 mRNA. FISH showed that the new-formed islet cells of group C contained SRY gene in Y chromosome and insulin double positive cells. Conclusion BMSCs can differentiate into IPCs in diabetic pancreatic microenvironment of pigs.
Objective To summarize the recent advance in the research of tissue engineered nerve grafts. Methods The cl inical and experimental research papers about tissue engineered nerve grafts were extensively reviewed and analyzed. Results The porosity, mechanical property and surface topography of a nerve scaffold, which was either made up of natural biodegradable polymers or synthetic polyesters, were pivotal factors that influenced the capacity of the scaffold in supporting nerve regeneration. Of various candidate supporting cells for nerve tissue engineering, the bone marrowmesenchymal stem cells had been paid more attention because of their advantages. Several model designs of drug del ivery systems for controlled release of growth factors had been attempted. In cl inical settings, short nerve gaps were demonstrated to be treatable with several nerve conduits which were commercially available, with functional recovery approximating tonerve autografting. Conclusion The field of nerve tissue engineering has witnessed a rapid development not only in experimental research but also in cl inical appl ication.
Objective To explore the impact of basic fibroblast growth factor (bFGF) and parathyroid hormone-related protein (PTHrP) on early and late chondrogenic differentiation of rabbit bone marrow mesenchymal stem cells (BMSCs) induced by transforming growth factor β1 (TGF-β1). Methods BMSCs were isolated from 3 healthy Japanese rabbits (2-month-old, weighing 1.6-2.1 kg, male or female), and were clutured to passage 3. The cells were put into pellet culture system and were divided into 5 groups according to different induce conditions: TGF-β1 group (group A), TGF-β1/bFGF group (group B), TGF-β1/21 days bFGF group (group C), TGF-β1/PTHrP group (group D), and TGF-β1/21 days PTHrP group (group E). At the beginning, TGF-β1 (10 ng/mL) was added to all groups, then bFGF and PTHrP (10 ng/mL) were added to groups B and D respectively; bFGF and PTHrP (10 ng/mL) were added to groups C and E at 21 days respectively. The gene expressions of collagen type I (Col I), Col II, Col X, matrix metalloproteinases (MMP)-13, and alkaline phosphatase (ALP) activity were detected once every week for 6 weeks. The 1, 9-dimethylmethylene blue (DMMB) staining was used to observe the extracellular matrix secretion at 6 weeks. Results The expression of Col I in groups C and E showed a significant downward trend after 3 weeks; the expression in group A was significantly higher than that in groups C and E at 4 and 5 weeks (P lt; 0.05), and than that in groups B and D at 3-6 weeks (P lt; 0.05); and significant differences were found between groups B and C at 3 and 4 weeks, and between groups D and E at 3 weeks (P lt; 0.05). After 3 weeks, the expressions of Col II and Col X in groups C and E gradually decreased, and were significantly lower than those in group A at 4-6 weeks (P lt; 0.05). Groups B and D showed no significant difference in the expressions of Col II and Col X at all time points, but there was significant difference when compared with group A (P lt; 0.05). MMP-13 had no obvious expression at all time points in group A; significant differences were found between group B and groups A, C at 3 weeks (P lt; 0.05); and the expression was significantly higher in group D than in groups A and E (P lt; 0.05). ALP activity gradually increased with time in group A; after 4 weeks, ALP activity in groups C and E obviously decreased, and was significantly lower than that in group A (P lt; 0.05); there were significant differences between groups B and C, and between groups D and E at 2 and 3 weeks (P lt; 0.05). DMMB staining showed more cartilage lacuna in group A than in the other groups at 6 weeks. Conclusion bFGF and PTHrP can inhibit early and late chondrogenic differentiation of BMSCs by changing synthesis and decomposition of the cartilage extracellular matrix. The inhibition is not only by suppressing Col X expression, but also possibly by suppressing other chondrogenic protein.
Objective To explore the osteogenesis and angiogenesis effect of bone marrow mesenchymal stem cells (BMSCs) derived osteoblasts and endothelial cells compound with chitosan/hydroxyapatite (CS/HA) scaffold in repairing radialdefect in rats. Methods The BMSCs were isolated from Sprague Dawley rats and the 3rd generation of BMSCs were induced into osteoblasts and endothelial cells. The endothelial cells, osteoblasts, and mixed osteoblasts and endothelial cells (1 ∶ 1) were compound with CS/HA scaffold in groups A, B, and C respectively to prepare the cell-scaffold composites. The cell proliferation was detected by MTT. The rat radial segmental defect model was made and the 3 cell-scaffolds were implanted, respectively. At 4, 8, and 12 weeks after transplantation, the graft was harvested to perform HE staining and CD34 immunohistochemistry staining. The mRNA expressions of osteopontin (OPN) and osteoprotegerin (OPG) were detected by RT-PCR. Results Alkal ine phosphatase staining of osteoblasts showed that there were blue grains in cytoplasm at 7 days after osteogenic induction and the nuclei were stained red. CD34 immunocytochemical staining of the endothelial cells showed that there were brown grains in the cytoplasm at 14 days after angiogenesis induction. MTT test showed that the proliferation level of the cells in 3 groups increased with the time. HE staining showed that no obvious osteoid formation, denser microvessel, and more fibrous tissue were seen at 12 weeks in group A; homogeneous osteoid which distributed with cord or island, and many osteoblast-l ike cells were seen in groups B and C. The microvessel density was significantly higher in groups A and C than group B at 3 time points (P lt; 0.05), and in group A than in group C at 12 weeks (P lt; 0.05). The OPN and OPG mRNA expressions of group A were significantly lower than those of groups B and C at 3 time points (P lt; 0.05). In groups B and C, the OPN mRNA expressions reached peak t8 and 12 weeks, respectively, and OPG mRNA expressions reached peak at 4 weeks. Conclusion BMSCs derived steoblasts and endothelial cells (1 ∶ 1) compound with CS/HA porous scaffold can promote bone formation and vascularization in bone defect and accelerate the healing of bone defect.