ObjectiveTo evaluate the effect of using Schwann-like cells derived from human umbilical cord blood mesenchymal stem cells (hUCBMSCs) as the seed cells to repair large sciatic nerve defect in rats so as to provide the experimental evidence for clinical application of hUCBMSCs. MethodsFourty-five male Sprague Dawley (SD) rats in SPF grade, weighing 200-250 g, were selected. The hUCBMSCs were harvested and cultured from umbilical cord blood using lymphocyte separating and high molecular weight hydroxyethyl starch, and then was identified. The hUCBMSCs of 3rd generation were induced to Schwann-like cells, and then was identified by chemical derivatization combined with cytokine. The acellular nerve basal membrane conduit was prepared as scaffold material by the sciatic nerve of SD rats through repeated freezing, thawing, and washing. The tissue engineered nerve was prepared after 7 days of culturing Schwann-like cells (1×107 cells/mL) on the acellular nerve basal membrane conduit using the multi-point injection. The 15 mm sciatic nerve defect model was established in 30 male SD rats, which were randomly divided into 3 groups (10 rats each group). Defect was repaired with tissue engineered nerve in group A, with acellular nerve basal membrane conduit in group B, and with autologous sciatic nerve in group C. The nerve repair was evaluated through general observation, sciatic function index (SFI), nerve electrophysiology, weight of gastrocnemius muscle, and Masson staining after operation. ResultsThe hUCBMSCs showed higher expression of surface markers of mesenchymal stem cells, and Schwann-like cells showed positive expression of glia cell specific markers such as S100b, glial fibrillary acidic protein, and P75. At 8 weeks after operation, the acellular nerve basal membrane conduit had no necrosis and liquefaction, with mild adhesion, soft texture, and good continuity at nerve anastomosis site in group A; group B had similar appearance to group A; adhesion of group C was milder than that of groups A and B, with smooth anastomotic stoma and no enlargement, and the color was similar to that of normal nerve. SFI were gradually decreased, group C was significantly greater than groups A and B, group A was significantly greater than group B (P<0.05). The compound action potential could be detected in anastomotic site of 3 groups, group C was significantly greater than groups A and B, and group A was significantly greater than group B in amplitude and conduction velocity (P<0.05). Atrophy was observed in the gastrocnemius of 3 groups; wet weight's recovery rate of the gastrocnemius of group C was significantly greater than that of groups A and B, and group A was significantly greater than group B (P<0.05). Masson staining showed that large nerve fibers regeneration was found in group A, which had dense and neat arrangement with similar fiber diameter. The density and diameter of medullated fibers, thickness of myelinated axon, and axon diameter of group C were significantly greater than those of groups A and B, and group A was significantly greater than group B (P<0.05). ConclusionTissue engineered nerves from hUCBMSCs-derived Schwann-like cells can effectively repair large defects of the sciatic nerve. hUCBMSCs-derived Schwann-like cells can be used as a source of seed cells in nerve tissue engineering.
Objective To observe the effects of cryopreservation and resuscitation on the biological characteristics of mesenchymal stem cells (MSCs) derived f rom human umbilical cord blood. Methods MSCs were isolated and cultured f rom human umbilical cord blood in vitro. The cells were passaged , and the third generation of MSCs were cryopreserved in－196 ℃ liquid nitrogen for 4 weeks with cryopreservation medium , which contained 10 % dimethyl sulfoxide (DMSO) and 90 % fetal calf serum ( FCS) . The morphology , proliferation and differentiation of MSCs were investigated and compared with those of MSCs before cryopreservation. Results There was no significant difference of morphology between pre-cryopreserved MSCs and the ones af ter resuscitation. It was observed that all MSCs were spindle-shaped and showed adherence growth characteristic before and af ter cryopreservation. The cell growth curves of MSCs were also similar before and af ter cryopreservation. Even though the curve of resuscitated MSCs descended a little as compared with that of pre-cryopreserved MSCs , there was no significant difference ( Pgt; 0. 05) . After 2-week adipocytic differentiation induction , fat drops could be found in the kytoplasm of MSCs and they were red when stained with oil-red O staining , which suggested that MSCs could be induced and differentiated into adipocytes. Af ter 4-week osteoblastic differentiation induction , MSCs could be induced and differentiated into osteoblasts , and calcium node showed black when stained with Von Kossa staining. There were no significant changes of the differentiating ability of MSCs into adipocyte and osteoblast before and after cryopreservation. Conclusion MSCs derived from human umbilical cord blood maintains their biological characteristics af ter cryopreservation and resuscitation.
Objective To investigate the effect of the serum from severe burn patients on the biology characteristics of human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro, so as to explore the feasibility of hUCMSCs transplantation for treating severe burn. Methods The 3rd passage of hUCMSCs were randomly divided into 3 groups: 10% fetal bovine serum group (group A), 10% normal serum group (group B), and 10% burn serum group (group C). At 24 hours, 72 hours, and 6 days after culture, the cell morphology and density were observed by inverted microscope; the cell proliferation was assessed by MTT; after 6 days of culture, the cell cycle by propidium iodide staining and flow cytometry, the apoptosis by acridine orange/ethidium bromide staining, and the cell senescence by β-galactosidase staining; the levels of tumor necrosis factor α (TNF-α), interleukin 1 (IL-1), platelet-derived growth factor (PDGF), and insulin-like growth factor 1 (IGF-1) in serum were detected by a double-antibody sandwich ELISA kit. Results hUCMSCs were long spindle/polygon in 3 groups. The cell fusion of group C was obviously faster than that in group A and group B. The cell proliferation curves showed that the velocity and number of cell proliferation in group C were significantly higher than those in group A and group B at 2-6 days after culture (P lt; 0.05). The rates of proliferation period (S) of hUCMSCs were 9.21% ± 1.02%, 11.79% ± 1.87%, and 20.54% ± 2.03%, respectively in groups A, B, and C at 6 days, and group C was significantly higher than that of group A and group B (P lt; 0.05). The hUCMSCs showed normal morphology and structure in 3 groups, and no apoptosis cells was observed. The positive cells percentage of group C (2.6% ± 0.1%) was significantly lower than that of group A (4.8% ± 0.2%) and group B (3.8% ± 0.4%) (P lt; 0.05). The levels of TNF-α, IL-1, PDGF, and IGF-1 in group C were significantly higher than those in group B (P lt; 0.05). Conclusion The higher levels of cytokines in serum from the severe burn patients can significantly stimulate hUCMSCs proliferation, prevent cells apoptosis, and reduce cells senescence. Therefore, it is feasible to use hUCMSCs transplantation for treating severe burn patients.
Objective To investigate the method and conditions of isolation，proliferation of multipotent mesenchymal stem cells（MSCs）from human umbilical cord blood in vitro, and to induce osteogenic and adipogenic differentiation directly for identification. Methods Human umbilical cord blood was collected in asepsis condition, isolated by density gradient centrifugation,or sedimented red cell with methylcellulose, and then the same centrifugation was done, or obtained by negative immunodepletion of CD34+. These isolated mononuclear cells were used to carry on plastic adherent culture. To obtain single cellderived colonies, these cells were proliferated clonally in medium which consists of L-DMEM orMesencultTM medium and 10% fetal calf serum（FCS） respectively, then their differentiation potentiality to osteoblasts and lipoblasts was tested. Results The mononuclear cells isolated by sedimented and centrifugated way cultured in MesencultTM medium and 10%FCS were most available. These adhesive cells could become obviously short rodshape or shuttle-shape cells after 5-7 days.The colonies form well in 3rdpassage cells. The mononuclear cells obtained by onlycentrifugalized in density gradient were hard to form colony, isolated by immunomagnetic beads were hard to culture. The surface antigens of these colonies cells presented CD29, CD59, CD71 but not CD34,CD45 and HLADR etc. The colony cells differentiating into osteoblasts that produce mineralized matrices, stained by alizarin red, and differentiating into adipocytes that accumulate lipid vacuoles, stained by oil red. Conclusion MSCs can be isolated from human umbilical cord blood and proliferate it in vitro. The way that mononuclear cells are sedimented red cell by methylcellulose and cultured by MesencultTM medium and 10% FCS is the valid method of isolation. Proliferation colonies cells present matrix cell immunophenotypes, and candifferentiate into osteoblasts and adipocytes.
Objective To investigate the feasibility of differentiating human umbilical cord blood stem cells into hepatocytes. Methods Thirty-six BALB/c nude mice were randomly divided into experimental group and control group(18 in each of the group), and experimental group was again randomly divided into group A， B and C (six in each of the group). The mice in experimental group and control group were exposed to 350 cGy radiation produced by 60Ｃｏ. After 3 h, karyocytes at different concentrations in the fresh human umbilical cord blood were injected into the mice in experimental group A, B, C via their tail veins, and the equal volume of normal sodium (NS) was also injected into control group via tail veins. After one month, carbon tetrachloride (CCl4) was injected into experimental group A, B and control group via abdominal cavity, and the equal volume of normal sodium was injected into experimental group C. After two months, immunohistochemistry and reverse transcriptase polymerase chain reaction (RT-PCR) were used to detect the expressions of human cytokeratin-18 (CK18), cytokeratin-19 (CK19) and albumin (ALB) in liver tissues of all mice. Results The expressions of CK18, CK19 and ALB in injured liver tissues were all positive, and the expressions of experimental group B were higher than those of experimental group A （P＜0.05）, but the expressions of CK18, CK19 and ALB in the liver tissues of control group and experimental group C, whose were not injured with CCl4, were all negative. Conclusion Human umbilical cord blood-derived stem cells can differentiate into hepatocytes and express ALB under special microenvironment after liver injured by CCl4 , and the expression level of ALB maybe directly related to the number of human umbilical cord blood stem cells.
ObjectiveTo obtain the mesenchymal stem cells (MSCs) from human umbilical cord and mark in vitro, for further transplantation therapy. MethodsThe MSC were isolated from human umbilical cord by tissue explants culture method. After subculture in vitro, the morphology of hUC-MSC was observed; the surface antigens of hUC-MSC were detected by flow cytometry; adipogenic and osteogenic differentiation were determined by specific staining; hUC-MSC labelled with Brd U were identified by immunofluorescence. ResultsMSC could be isolated successfully by tissue explants culture method. When cultured about one week, the cells climbed out from the tissue block edge, proliferated and formed colonies; the hUC-MSCs of passage 5 were detected by flow cytometry, and they highly expressed CD73, CD90 and CD105, didn't express or lowly expressed CD14, CD34, CD45, CD79a and human leukocyte antigen-DR. After two weeks of adipogenic induction, they were positive in oil red O staining, and after three weeks of osteogenic induction, red precipitate could be seen by alizarin red staining, and the red fluorescence of the hUC-MSC labelled with Brd U could be detected by immunofluorescence detection. ConclusionThe cells can be isolated from human umbilical cord by tissue explants culture method, with the characteristics of hUC-MSCs and can be labeled successfully in vitro, so it can be used for the research in the field of cell transplantation.
This research was to study the regulation of intravenous administration of human umbilical cord blood mesenchymal stem cells (HUCBMSCs) on secretion of neural specific protein in rats after traumatic brain injury (TBI), and to explore its mechanisms promoting the recovery of neurological function. The TBI models of rats were established. We then injected HUCBMSCs, labelled by Brdu (5-bromo-2-deoxyuridine), into the TBI rats via the tail vein using modified Feeney free-falling method. The levels of neural biochemical indicators (serum S100βprotein, NSE, LDH, CK) of rats were detected in shamed group, injury group and HUCBMSCs-transplanted group. And the morphological changes of brain tissue of rats in the three groups were observed by using HE staining under light microscope. During the whole experiment no immunosuppressant was used for the four groups. From the research, transplant-related death of the rats was not found in transplantation group. In the injury group, rises were found in contents of serum S100βprotein, NSE, LDH, CK in the early stage after the rats were injured, which were much higher than those in shamed group at correspondent time point(P < 0.01). In HUCBMSCs-transplanted group, although these biochemistry indexes were found rising for a short period in the early stage, along with the time, these indexes were obviously lower than in those injury group (P < 0.05). Under light microscopy pathological changes of rats in HUCBMSCs-transplanted group were much slighter than those in injury group. It was well concluded that in the situation of no immuno-suppressants, the intravenous-injected HUCBMSCs could reduce the secretion of serum S100βprotein, NSE, LDH, CK, promote the repair of tissue injury effectively, and promote the functional recovery of neurons.
ObjectiveTo study the characteristics of the human umbilical cord perivascular cells (HUCPVC) isolated from human first trimester umbilical cord perivascular layer tissues and the differentiation into islet-like cell clusters in vitro. MethodsThe HUCPVC derived from human first trimester umbilical cord which was donated by the volunteers were isolated and subcultured. The surface markers such as stage-specific embryonic antigen 1 (SSEA-1), SSEA-3, SSEA-4, OCT-4, TRA-1-60, and TRA-1-81 were detected by immunohistochemical method. The first trimester HUCPVC were induced to embryoid bodies (EB)-like cell aggregations and islet-like cell clusters in vitro through a simple stepwise culture protocol (5 steps). The expressions of specific markers[α-fetoprotein (AFP), Nestin, and smooth muscle actin (SMA)] were measured by immunohistochemical method; and the ability of glucose-stimulated insulin secretion was analyzed. ResultsThe first trimester HUCPVC were successfully isolated and could be passaged steadily more than 10 generations, which expressed SSEA-3, SSEA-4, OCT-4, TRA-1-61, and TRA-1-81. The first trimester HUCPVC were successfully induced into EB-like cell aggregations and islet-like cell clusters. The EB-like cell aggregations could express markers of three germ lineages:AFP, Nestin, and SMA. The islet-like cell clusters could release insulin significantly in response to elevated concentrations of glucose in vitro (t=7.444, P=0.002). The insulin contents were (23.2±5.3) mU/L and (7.0±0.5) mU/L in high and low glucose media, respectively. ConclusionThe first trimester HUCPVC has the ability to differentiate into islet-like cell clusters which can secret insulin in vitro.
ObjectiveTo assess the role and effect of Wharton's jelly of human umbilical cord oriented scaffold on chondrocytes co-cultured in vitro. MethodsChondrocytes from shoulder cartilage of adult New Zealand rabbits were isolated,cultured,amplified,and labelled using fluorescent dye PKH26.Cells were extracted from human umbilical cord tissue using wet-grinding chemical technology to prepare the Wharton's jelly of human umbilical cord oriented scaffold by freeze-drying and cross-linking technology.Second generation of chondrocytes were cultured with Wharton's jelly of human umbilical cord oriented scaffold.Inverted microscope and scanning electron microscope (SEM) were used to observe the cell distribution and adhesion on the scaffold; extracellular matrix secretion of the chondrocytes were observed by toluidine blue and safranin O staining.Cells distribution and proliferation on the scaffold were assessed by fluorescein diacetate-propidium iodide (FDA-PI) and Hoechst33258 staining.The viability of the in vitro cultured and PKH26 fluorescence labelled chondrocytes on the scaffold were assessed via fluorescence microscope. ResultsInverted microscope showed that the cells cultured on the scaffold for 3 days were round or oval shaped and evenly distributed into space of the scaffold.SEM observation showed that large number of cultured cells adhered to the pores between the scaffolds and were round or oval shape,which aggregated,proliferated,and arranged vertically on longitudinally oriented scaffold at 7 days after culture.Histological observation showed that cells distributed and proliferated on the scaffold,and secreted large amount of extracellular matrix at 7 days.Scaffold could guide cell migration and proliferation,and could effectively preserve and promote the secretion of extracellular matrix.Cell viability assessments at 3 days after culture showed most of the adhered cells were living and the viability was more than 90%.PKH26 labelled chondrocytes were seen,which distributed uniformly along the pore of oriented scaffold,and exuberantly proliferated. ConclusionWharton's jelly of human umbilical cord oriented scaffold favors adhesion,proliferation,and survival of chondrocytes.It possesses a favorable affinity and cell compatibility.Thus,it is an ideal scaffold for cartilage tissue engineering.
ObjectiveTo observe the growth characteristics of human umbilical cord mesenchymal stem cells (hUCMSCs) cultured on the alginate gel scaffolds and to explore the feasibility of hUCMSCs-alginate dressing for wound healing. MethodshUCMSCs were separated from human umbilical cords and cultured in vitro. After the 4th passage cells were co-cultured with alginate gel (experimental group), the cell growth characteristics were observed under the inverted phase contrast microscope. Vascular endothelial growth factor (VEGF) content was measured and the number of cells was counted at 0, 3, 6, and 9 days after culture; and the cell migration capacity was observed. The hUCMSCs were cultured without alginated gel as control. The model of full-thickness skin defects was established in 32 8-weekold Balb/c male mice and they were randomly divided into 4 groups (n=8): wounds were covered with hUCMSCsalginate gel compound (MSC-gel group), cell supernatants-alginate gel compound (CS-gel group), 10% FBS-alginate gel compound (FBS-gel group), and 0.01 mol/L PBS-alginate compound (PBS-gel group), respectively. Wound healing rates at 5, 10, and 15 days were observed and calculated; and the wound tissues were harvested for histological and immunohistochemical staining to assess new skin conditions at 15 days after operation. ResultshUCMSCs grew well with grape-like proliferation on the alginate gel, but no cell migration was observed at 7 days after cultivation. VEGF expression and cell number in experimental group were significantly less than those in control group at 3 days（P<0.05）; then they gradually increased, and VEGF expression and cell number were significantly more than those in control group at 9 days (P<0.05). The wound healing rates of MSC-gel and CS-gel groups were significantly higher than those of FBSgel and PBS-gel groups at 5, 10, and 15 days (P<0.05). The squamous epithelium, fibroblasts, sebaceous glands, capillaries and VEGF expression of the new skin in MSC-gel and CS-gel groups were significantly more than FBS-gel and PBS-gel groups (P<0.05). But there was no significance between MSC-gel and CS-gel groups (P>0.05). ConclusionhUCMSCs can continuously express VEGF in alginate gel, which is necessary for wound healing. The hUCMSCs-alginate compound is probably a good wound dressing.