Objective To summarize and review the heterogeneity of bone marrow derived stem cells (BMDSCs) and its formation mechanism and significance, and to analyze the possible roles and mechanisms in intestinal epithel ial reconstruction. Methods The related l iterature about BMDSCs heterogeneity and its role in intestinal epithel ial repair was reviewed and analyzed. Results The heterogeneity of BMDSCs provided better explanations for its multi-potency. The probable mechanisms of BMDSCs to repair intestinal epithel ium included direct implantation into intestinal epithel ium, fusion between BMDSCs and intestinal stem cells, and promotion of injury microcirculation reconstruction. Conclusion BMDSCs have a bright future in gastrointestinal injury caused by inflammatory bowl disease and regeneration.
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.
Objective To investigate the effect of homograft of marrow mesenchymal stem cells (MSCs) seeded onto poly-L-lactic acid (PLLA)/gelatin on repair of articular cartilage defects. Methods The MSCs derived from36 Qingzilan rabbits, aging 4 to 6 months and weighed 2.5-3.5 kg were cultured in vitroand seeded onto PLLA/gelatin. The MSCs/ PLLA/gelatin composite was cultured and transplanted into full thickness defects on intercondylar fossa. Thirty-six healthy Qingzilan rabbits were made models of cartilage defects in the intercondylar fossa. These rabbits were divided into 3 groups according to the repair materials with 12 in each group: group A, MSCs and PLLA/gelatin complex(MSCs/ PLLA/gelatin); group B, only PLLA/gelatin; and group C, nothing. At 4,8 and 12 weeks after operation, the gross, histological and immunohistochemical observations were made, and grading scales were evaluated. Results At 12 weeks after transplantation, defect was repaired and the structures of the cartilage surface and normal cartilage was in integrity. The defects in group A were repaired by the hylinelike tissue and defects in groups B and C were repaired by the fibrous tissues. Immunohistochemical staining showed that cells in the zones of repaired tissues were larger in size, arranged columnedly, riched in collagen Ⅱ matrix and integrated satisfactorily with native adjacent cartilages and subchondral bones in group A at 12 weeks postoperatively. In gross score, group A(2.75±0.89) was significantly better than group B (4.88±1.25) and group C (7.38±1.18) 12 weeks afteroperation, showing significant differences (P＜0.05); in histological score, group A (3.88±1.36) was better than group B (8.38±1.06) and group C (13.13±1.96), and group B was better than group C, showing significant differences (P＜0.05). Conclusion Transplantation of mesenchymal stem cells seeded onto PLLA/gelatin is a promising way for the treatment of cartilage defects.
Objective To investigate the method and clinical effect of free iliac flap grafting in repairing the tibia traumatic osteomyelitis complicated withboneskin defect. Methods From June 2001 to February 2006，28 patients with tibia traumatic osteomyelitis complicated with boneskin defect were treated with free iliac flap grafting at stageⅠ. There were 18 males and 10 females, with an average of 32.5 years(1868 years). There were traffic injury in 11 cases, bruise in 6 cases, explosive injury in 5 cases, machinery injury in 4 cases, and falling injury in 2 cases. The disease courses of patients were 1-6 months. All patients had been treated by 26 operations. The wounds located at the mid and upper tibia in 13 cases, and the inferior tibia in 15 cases. The length of free iliac was0.5-6.0 cm and the size of the flap ranged from 4.5 cm×3.5 cm to 28.0 cm×16.0 cm.The external fixation were applied in 18 cases, and steel plate were applied in 10 cases. The donor sites were sutured directly. Results All of the flaps survived completely. The wounds healed by first intention in 26 cases and by second intention in 2 cases. The donorsites healed by first intention. Twentyeight patients were followed up for 6 to 56 months(mean, 30 months).The appearances of the flaps were satisfactory and the colour was similar to recipient site. All grafted bone united 2-14 months (mean，4.6 months) after operation according to X-ray examination. In 20 patients who did not achieved union before operation, fracture healed 2 to 6 months after operation(mean, 3.2 months). Osteomyelitis recurred 12 months after operation in 2 cases and healed by nidus clearing. Conclusion Free iliac flap which used to repair tibia traumatic osteomyelitis complicated with boneskin defect, can repair the defect at stageⅠand enhance the antiinfectious ability. It isone of appropriate and effective clinical methods.
Objective To explore the relationship of the limited resource of the autologous bone marrow mesenchymal stem cells (MSCs) in articularcavity to the treatment results of full-thickness articular cartilage defect, and to investigate whether the extrogenous sodium hyaluronate(SH) promotes the migration of MSCs cultured in vitro tothe articular defect in vivo. Methods Sixty-six Japan rabbits were made the model of the full-thickness articular cartilage defect (5 mm width and 4 mm depth).The autologous MSCs were extracted from the rabbit femur, cultured in vitro, labeledby Brdu, and injected into the injured articular cavity with or without SH. Theexperiment was divided into 4 groups; group A (MSCs and SH, n=15); group B (MSCs, n=15); group C (SH, n=18); and group D (non-treatment, n=18). The morphologic observation was made by HE staining, Mallory staining and immunohistochemical staining after 5 weeks, 8 weeks and 12 weeks of operation. Results There were significant differences in the thickness of repairing tissue between group A and group B(Plt;0.01); but there were no significant differences between group A and group C, and between group B and group D(P＞0.05). Thehistological observation showed that the main repairing tissue was fibrocartilage in group A and fiber tissue in group B. Conclusion MSCs cultured in vitro and injected into the articular cavity can not improve the treatment results of the articular cartilage defect. Extrogenous SH has effect on repairing cartilage defect. The extrogenous SH has no effect on the chemotaxis of the MSCs, and on the collection of MSCs into the joint defect.
OBJECTIVE: To investigate the effects of dexamethasone on the proliferation and differentiation of bone marrow stromal cells(MSC). METHODS: MSC were isolated and cultured in vitro. After treatment with different concentrations of dexamethasone (0, 10-10, 10-9, 10-8, 10-7 and 10-6 mol/L), the proliferation and alkaline phosphatase (ALP) activity of MSC were measured to evaluate the effect of dexamethasone on the biological characteristics of MSC. RESULTS: Dexamethasone inhibited cell proliferation. With the increase of concentration of dexamethasone, the effect was enhanced, which was more significant when the concentration of dexamethasone was over 10-8 mol/L. At the same time, dexamethasone promoted the activity of ALP. This effect was enhanced with the increase of concentration of dexamethasone, but the alteration was small when the concentration of dexamethasone was over 10-8 mol/L. The effects increased with the time. The activity of ALP was enhanced 2 to 4 times with the dexamethasone for 6 days. CONCLUSION: Dexamethasone inhabit the proliferation of MSC, while induce them to differentiate into osteoblasts. The appropriate concentration of dexamethasone was 10-8 mol/L.
OBJECTIVE: From the point of view of material science, the methods of tissue repair and defect reconstruct were discussed, including mesenchymal stem cells (MSCs), growth factors, gene therapy and tissue engineered tissue. METHODS: The advances in tissue engineering technologies were introduced based on the recent literature. RESULTS: Tissue engineering should solve the design and preparation of molecular scaffold, tissue vascularization and dynamic culture of cell on the scaffolds in vitro. CONCLUSION: Biomaterials play an important role in the tissue engineering. They can be used as the matrices of MSCs, the delivery carrier of growth factor, the culture scaffold of cell in bioreactors and delivery carrier of gene encoding growth factors.
Objective To explore the in vitrodifferentiation of the rat mesenchymal stem cells (MSCs ) into the skeletal muscle cells induced by the myoblast differentiation factor (MyoD) and 5-azacytidine. Methods The MSCs were taken from the rat bone marrow and the suspension of MSCs was made and cultured in the homeothermia incubator which contained 5% CO2at 37℃. The cells were observed under the inverted phase contrast microscope daily. The cells spreading all the bottom of the culture bottle were defined as onepassage. The differentiation of the 3rd passage of MSCs was induced by the combination of 5-azacytidine, MyoD, transforming growth factor β1, and the insulin like growth factor 1. Nine days after the induction, the induced MSCs were collected, which were analyzed with the MTT chromatometry, theflow cytometry, and the immunohistochemistry. Results The primarily cultured MSCs grew as a colony on the walls of the culture bottle; after the culture for 5-7 days, the cells were shaped like the fibroblasts, the big flat polygonal cells, the medium sized polygonal cells, and the small triangle cells; after the culture for 12 days, the cells were found to be fused, spreadingall over the bottle bottom, but MSCs were unchanged too much in shape. After the induction by 5-azacytidine, some of the cells died, and the cells grew slowly. However, after the culture for 7 days, the cells grew remarkably, the cell volume increased gradually in a form of ellipse, fusiform or irregularity. After theculture for 14 days, the proliferated fusiform cells began to increase in a great amount. After the culture for 18-22 days, the myotubes increased in number and volume, with the nucleus increased in number, and the newly formed myotubes and the fusiform myoblst grew parallelly and separately. The immunohistochemistry for MSCs revealed that CD44 was positive in reaction, with the cytoplasm ina form of brown granules. And the nucleus had an obvious border，and CD34 was negative. The induced MSCs were found to be positive for desmin and specific myoglobulin of the skeletal muscle. The flow cytometry showed that most of the MSCs and the induced MSCs were in the stages of G0/G1，accounting for 79.4％ and 62.9％，respectively; however, the cells in the stages of G2/S accounted for 20.6％ and 36.1％. The growth curve was drawn based on MTT，which showed that MSCs weregreater in the growth speed than the induced MSCs. The two kinds of cells did not reach the platform stage，having a tendency to continuously proliferate.ConclusionIn vitro,the rat MSCs can be differentiated into the skeletal muscle cells with an induction by MyoD and 5-azacytidine, with a positive reaction for the desmin and the myoglobulin of the skeletal muscle. After the induction, the proliferation stage of MSCs can be increased, with a higher degree of the differentiation into the skeletal muscle.
Objective To investigate the effect of bone marrow mesenchymal stem cell (MSCs) transp1antation combined with transmyocardial drilling revascularization (TMDR) and degradable stent on myocardium revascu1arization after acute myocardial infarction(AMI), and to provide the experimental evidence for surgical treatment of myocardial infarction. Methods After established models of AMI, the 24 pigs were divided into four groups with random number table, 6 pigs each group. Control group: only established models of AMI; MSCs group: AMI immediately followed by MSCs implantation; TMDR combined with stent group: AMI followed by TMDR and absorbable basic fibroblast growth factor (bFGF) stent implantation; MSCs combined with TMDR and stent group: AMI followed by TMDR and absorbable bFGF stent implantation, and then MSCs implantation. Three months after operation, the infarcted areas and vessel density in infarcted zone were detected by histopathology method. Results Three months after operation, the histopathological examination showed that infarcted areas in MSCs group, TMDR combined with stent group, and MSCs combined with TMDR and stent group were decreased as compared with control group （27.9%±3.1% vs. 48.9%±2.7%，P=0.000；20.3%±1.7% vs. 48.9%±2.7%，P=0.000；12.5%±1.9% vs. 48.9%±2.7%，P=0.000）; and vessel density was further increased （8.4±1.2/HP vs.4.5±14/HP，P=CM(1583mm] 0.001；11.5±2.6/HP vs.4.5±1.4/HP，P=0.001;15.6±1.4/HP vs.4.5±1.4/HP，P=0.000）. Conclusion [CM)]MSCs transplantation combined with TMDR and absorbable bFGF stents implantation could significantly reduce the infarction areas, increase the vessel density. This method may enhance the efficacy of MSCs transplantation in acute cardiac infarction model, which provide a new ideas for the surgical treatment of myocardial infarction.
Objective To study the effect of autogenous bone marrow on guided bone regeneration (GBR),and evaluate the repairing ability of GBR in bone defect with autogenous bone marrow. Methods Ten mm segmental defects were produced in both radii of 18 rabbits. The defect was bridged with a silicon tube. Autogenous bone marrow was injected into the tube on the experimental group at 0, 2,4 weeks after operation, and peripheralblood into the control group at thesame time. The X-ray, gross, histological and biochemical examinations were observed invarious times. Results The new bone formation of experimental group was prior to that of control group; calcium and alkaline phosphatase of experimental groupwere higher than those of control group. The experimental group had all been healed at the tenth week, but no one healed in control group. Conclusion It can be conclude that autogenous bone marrow can stimulate bone formation and facilitate GBR in bone defect.