Tooth or dentition missing compromises human health physically and psychiatrically. Although several prosthesis methods are used to restore tooth loss, these restorations are still non-biological methods. It is a dream for human being to regenerate a real tooth for hundreds years. There are two ways to regenerate the tooth. One is application of conventional tissue engineering techniques including seed cells and scaffold. The other is regeneration tooth using dental epithelium and dental mesenchymal cells based on the knowledge of tooth initiation and development. Marked progress has been achieved in these two ways, while there is still a long way to go. Recently a new concept has been proposed for regeneration of a biological tooth root based on tooth-related stem cells and tissue engineering technique. A biological tooth root has been regenerated in swine. It may be a valuable method for restoration of tooth loss before successful whole tooth regeneration. A latest research showed that a subpopulation in bone marrow cells can give rise to ameloblast-like cells when mixed with embryonic epithelium and reassociation with integrated mesenchyme, which may provide a new seed cell source for tooth regeneration.

To investigate the perfusion restoration of type 1 diabetic mouse under the setting of surgically induced hind limb ischemia and the number and function of bone marrow endothelial progenitor cells (EPCs).

To investigate whether the recombinant baculovirus (Bac-CMV-EGFP) can effectively transduce into rhesus Bone-marrow derived Mesenchymal Stem Cells (rBMSCs) in vitro, and whether there are some efficiency to the rBMSCs of viability, proliferational and differentiational capacity after recombinant baculovirus transducing.

To explore an approach to isolate and culture the Adipose derived stem cells (ASCs) from the fatty and the fluid portions of liposuction aspirates, and to investigate the growth kinetics, morphology, differentiation capability, cell senescence, surface marker profiles of the ASCs.

To perform single cell clone culture of human adipose-derived stem cells (hASCs), and identify their surface antigens in different clones.

To investigate the association of HLA-A, B, and DRB1 alleles with leukemia in the Han population in Hunan Province.

To investigate the effects of Par-4 gene silencing induced by siRNA on the expression of Smac gene, activity of caspase-3, and apoptosis of human bone marrow mesenchymal stem cells (hBMSCs).

To summarize Notch, basic helix-loop-helix (bHLH) and Wnt gene signal transduction pathways in the process of differentiation and development of neural stem cells.

To study the effect of the repair of rabbit articular cartilage defects by the composite of chondrogenic induction of autologous MSCs and autologous "two-phase" bone matrix gelatin (BMG).

To study the feasibility of human adipose derived stem cells (ADSCs) in monolayer culture induced into smooth muscle cells in vitro as seeding cells in vascular tissue engineering.

To develop a method for reconstructing urothelial structures using tissue engineering techniques.

Stem cells are found in all human tissues, while tumor stem cells (TSCs) are also detected in tumors. TSC of breast cancer has been separated and its markers have been affirmed. However, TSC of lung carcinoma has not been separated yet. This study was to investigate the expression and significance of stem cell markers for breast cancer (CD44(+)ESA(+)CD24(-/low)) in non-small-cell lung carcinoma (NSCLC).

Spermatogonial stem cells (SSCs), the only stem cells that are capable of transmitting genetic information to subsequent generations in adult animals,have abilities to self-renew and differentiate into spermatozoa. Therefore, SSCs are not only the study object of stem cell biology, but also the valuable resource of in vitro spermatogenesis, gene analysis and functional genomics. In the present study, we selected the mouse SSCs from mice on STO (SIM mouse embryo-derived thioguanine and ouabain resistant) feeders by differential adherence selection in DMEM/F12 containing 5% FBS, and used a serum-free defined medium prepared with Knockout SR basal medium to culture SSCs. Our results showed that enriched SSCs could be maintained for a short of time and form colonies, but the proliferation of SSCs was unconspicuous, suggesting that some factors that are detrimental to the self-renewal of SSCs possibly existed in the Knockout SR basal medium. However, the use of KSR medium, which was widely used in the culture of embryonic stem cells (ESCs), in the SSC maintenance was the first time, and our results indicated that the Knockout SR basal medium don't appropriate for the long-time culture of SSCs.

The use of stem cells will lead to novel treatments for a wide range of diseases due to their properties of self-renewing, pluripotent, and undifferentiated state, and the stem cells are usually genetically modified for cell and gene therapy. If the baculovirus, as a new gene vector, can be effectively transduced into various mammalian bone marrow-derived mesenchymal stem cells (BMSCs) in vitro, it will be a better gene vector to genetically modify the stem cells. The aim of the present study is to investigate the transduction efficiency of recombinant baculovirus (BacV-CMV-EGFP), which expressed a reporter gene encoding enhanced green fluorescent protein (EGFP) under a cytomegalovirus immediate early (CMV-IE) promoter, into various mammalian BMSCs. The BMSCs of mouse, rat, porcine, rhesus, and human were cultured primarily in vitro. After more than three passages, the mammalian BMSCs were seeded into dishes and cultured in a humidified incubator at 37 °C with 5% CO(2). When the cells reached about 80% confluence, the complete medium was removed by aspiration. The cells were transduced with recombinant baculovirus at a multiplicity of infection (MOI) of 200 vector genomes/cell with 500 μL PBS at 25 °C for 4 h. At the end of baculovirus transduction, cells were washed and incubated with 2 mL complete medium, and baculovirus-transduced mammalian BMSCs were cultured in a humidified incubator for 2 d. Then, the inverted fluorescent microscope was used to observe GFP expressions in different mammalian BMSCs, and flow cytometry was used to detect the transduction efficiency of baculovirus in various mammalian BMSCs. After more than three passages, the BMSCs of mouse, rat, porcine, rhesus, and human showed a homogeneous spindle-shaped morphology. Compared with the BMSCs of mouse, rat and porcine, the inverted fluorescent microscope observations showed that there were more BMSCs expressing GFP and greater mean fluorescence intensity in rhesus and human transduced with baculovirus. The baculovirus could efficiently transduce into the BMSCs of mouse, rat, porcine, rhesus and human, and the transduction efficiency was (20.21±3.02)%, (22.51±4.48)%, (39.13±5.79)%, (71.16±5.36)% and (70.67±3.74)%, respectively. In conclusion, baculovirus displays different transduction efficiency into various mammalian BMSCs. Due to the high transduction efficiency for primate and human BMSCs, baculovirus is possibly a more suitable gene vector to genetically modify BMSCs of human and primates.

Strong proliferative capacity and the ability to differentiate into the derivative cell types of three embryonic germ layers are the two important characteristics of embryonic stem cells. To study whether the mesenchymal stem cells from human fetal bone marrow (hfBM-MSCs) possess these embryonic stem cell-like biological characteristics, hfBM-MSCs were isolated from bone barrows and further purified according to the different adherence of different kinds of cells to the wall of culture flask. The cell cycle of hfBM-MSCs and MSC-specific surface markers such as CD29, CD44, etc were identified using flow cytometry. The expressions of human telomerase reverse transcriptase (hTERT), the embryonic stem cell-specific antigens, such as Oct4 and SSEA-4 were detected with immunocytochemistry at the protein level and were also tested by RT-PCR at the mRNA level. Then, hfBM-MSCs were induced to differentiate toward neuron cells, adipose cells, and islet B cells under certain conditions. It was found that 92.3% passage-4 hfBM-MSCs and 96.1% passage-5 hfBM-MSCs were at G(0)/G(1) phase respectively. hfBM-MSCs expressed CD44, CD106 and adhesion molecule CD29, but not antigens of hematopoietic cells CD34 and CD45, and almost not antigens related to graft-versus-host disease (GVHD), such as HLA-DR, CD40 and CD80. hfBM-MSCs expressed the embryonic stem cell-specific antigens such as Oct4, SSEA-4, and also hTERT. Exposure of these cells to various inductive agents resulted in morphological changes towards neuron-like cells, adipose-like cells, and islet B-like cells and they were tested to be positive for related characteristic markers. These results suggest that there are plenty of MSCs in human fetal bone marrow, and hfBM-MSCs possess the embryonic stem cell-like biological characteristics, moreover, they have a lower immunogenic nature. Thus, hfBM-MSCs provide an ideal source for tissue engineering and cellular therapeutics.

The present study aimed to investigate the effect of proto-oncogene c-src on the viability of rat spermatogonial stem cells from 9 day-old rat in vitro. MTT method was used to observe the viability of the spermatogonial stem cells treated with antisense c-src oligodeoxynucleotides (ODNs) in vitro; RT-PCR was utilized to observe the expression of c-src mRNA and Western blot was used to observe the protein expressions of pp60c-src and phosphorylated signal transducer and activator of transcription-3 (p-STAT3). Compared with that in control group, the viability of spermatogonial stem cells decreased by 8.1% (P<0.05) and the expression of c-src mRNA decreased significantly after treatment with 10 μmol/L antisense c-src ODNs for 12 h. Compared with that in the control group, the protein expressions of pp60c-src and p-STAT3 decreased by 33.8% and 45.3% (both P<0.01), respectively, in the spermatogonial stem cells after being transfected with antisense c-src ODNs. The results suggest that proto-oncogene c-src regulates the viability of rat spermatogonial stem cells through p-STAT3.

Adipose-derived stem cells (ASCs) are similar to bone marrow mesenchymal stem cells (MSCs) in growth kinetics, antigen expression and multi-lineage differentiation capacity. The present study was designed to investigate the differences between ASCs and MSCs in in vitro culture and differentiation into cardiomyocytes. ASCs were isolated from the fat tissue of New Zealand white rabbits while MSCs were obtained from rat bone marrow. Both ASCs and MSCs were cultured in Iscove's modified Dulbecco's medium supplemented with 15% fetal bovine serum in the same incubator and treated with various concentrations of 5-azacytidine. A clonogenic assay was used to quantify ASCs in fat tissue and MSCs in bone marrow. The number of ASCs in the fat tissue was much higher than that of MSCs in the bone marrow quantified by clonogenic assay, and MSCs showed a remarkably slower proliferative rate compared with ASCs, especially at primary passage. ASCs began to attach to the bottom of the culture flask 12 h after seeding. The cells in culture assumed a short spindle shape under a phase-contrast microscope and did not form clusters. The phenotype was maintained through repeated subcultures under nonstimulating conditions. No other cell phenotype was observed. MSCs attached to the culture flask at 24-48 h after seeding and grew in clusters. The cells were fibroblast-like and prone to senescence or differentiation into adipose cells. Both ASCs and MSCs before treatment with 5-azacytidine were stained positively for CD29, CD44 and CD105 but negatively for CD34 and CD45, α-sarcromeric actin, cardiac troponin T and von Willebrand factor. ASCs differentiated into cardiomyocytes only after treatment with 6-9 μmol/L of 5-azacytidine, while MSCs differentiated into cardiomyocytes with 3-15 μmol/L of 5-azacytidine. After treatment with ideal dose of 5-azacytidine, ASCs began to change their morphology and showed multinucleation within the first week and formed a ball-like appearance thereafter, while MSCs showed multinucleation at the second week and formed a stick-like appearance at 3-4 weeks. The percentage of ASCs differentiated into cardiomyocytes after treatment with 5-azacytidine was significantly higher than that of MSCs. The age of animal had no significant influence on the tissue content, proliferation and differentiation rate of ASCs. However, the tissue content of MSCs in bone marrow decreased with increased age of animal and MSCs from old donor rats exhibited less myogenic cells than those from the young rats after exposure to 5-azacytidine. These results indicate that ASCs have advantages over MSCs in tissue content, homology, growth and differentiation rate, suggesting that ASCs are more suitable for cellular cardiomyoplasty than MSCs.

To investigate the effects of Xiehuo Bushen Decoction (XHBSD), a compound Chinese herbal medicine, on the survival and differentiation of transplanted neural stem cells (NSCs) in brains of rats with intracerebral hemorrhage, and to explore the mechanism of Xiehuo Bushen formula in promoting the survival of transplanted NSCs.

To evaluate the brain pathological changes following exdogenous neural stem cells (NSCs) intraventricular transplantation in neonatal rats with periventricular leukomalacia (PVL), and to explore the feasibility of NSCs transplantation for the treatment of PVL in premature infants.