Morphological Properties of Mesenchymal Stem Cells Derived from Bone Marrow of Rhesus Monkeys

To establish an in vitro system for isolating and culturing the mesenchymal stem cells （MSC） of Rhesus monkeys, and to provide research data for its further application, the bone marrow of Rhesus monkeys was collected and separated by gradient centrifugation to discard most of the blood cells. The MSC contained in the monocyte centrifuging layer was obtained and cultured in Dulbecco＇s modified media （low glucose, L-DMEM） supplemented with 10% Fetal bovine serum （FBS） and 1 ng/ml basic fibroblast growth factor （bFGF）. The non-MSC was screened out by continuously renewing the medium. A passage culture was undertaken while the MSC monolayer formed. The spindle-shaped MSC formed a monolayer after 18 days of primary culturing, and the cells appeared in an oriented array with a swirling and irradiating growth trend. In the anaphase of passage culture, the cell proliferation rate was decreased and the morphology changed into triangular, polygon and flat appearance. These results suggested that mesenchymal stem cells （MSC） of the Rhesus monkey can be passaged in vitro with the established optimized culture system.

Protective effects of ACLF sera on metabolic functions and proliferation of hepatocytes co-cultured with bone marrow MSCs in vitro

AIM： To investigate whether the function of hepatocytes co-cultured with bone marrow mesenchymal stem cells （MSCs） could be maintained in serum from acute-on- chronic liver failure （ACLF） patients.METHODS： Hepatocyte supportive functions and cy- totoxicity of sera from 18 patients with viral hepatitis B-induced ACLF and 18 healthy volunteers were evalu- ated for porcine hepatocytes co-cultured with MSCs and hepatocyte mono-layered culture, respectively. Chemo- kine profile was also examined for the normal serum and liver failure serum.RESULTS： Hepatocyte growth factor （HGF） and Tumor necrosis factor; tumor necrosis factor （TNF）-a were re- markably elevated in response to ACLF while epidermal growth factor （EGF） and VEGF levels were significantly decreased. Liver failure serum samples induced a higher detachment rate, lower viability and decreased liver sup- port functions in the homo-hepatocyte culture. Hepato-cytes co-cultured with MSCs could tolerate the cytotoxic- ity of the serum from ACLF patients and had similar liver support functions compared with the hepatocytes cul- tured with healthy human serum in vitro. In addition, co- cultured hepatocytes maintained a proliferative capability despite of the insult from liver failure serum.CONCLUSION： ACLF serum does not impair the cell morphology, viability, proliferation and overall metabolic capacities of hepatocyte co-cultured with MSCs in vitro.

北京大学推进实践育人工作的探索与实践

北京大学继承实践育人工作的优良传统,形成了"四结合、四促进"的实践育人理念,构建并完善全过程、全方位、全覆盖实践育人体系,实践育人工作取得良好成效。

Effects of intermittent negative pressure on osteogenesis in human bone marrow-derived stroma cells

Objective： We investigated the effects of intermittent negative pressure on osteogenesis in human bone marrowderived stroma cells （BMSCs） in vitro. Methods： BMSCs were isolated from adult marrow donated by a hip osteoarthritis patient with prosthetic replacement and cultured in vitro. The third passage cells were divided into negative pressure treatment group and control group. The treatment group was induced by negative pressure intermittently （pressure： 50 kPa, 30 min/times, and twice daily）. The control was cultured in conventional condition. The osteogenesis of BMSCs was examined by phase-contrast mi- croscopy, the determination of alkaline phosphatase （ALP） activities, and the immunohistochemistry of collagen type 1. The mRNA expressions of osteoprotegerin （OPG） and osteoprotegerin ligand （OPGL） in BMSCs were analyzed by real-time polymerase chain reaction （PCR）. Results： BMSCs showed a typical appearance of osteoblast after 2 weeks of induction by intermittent negative pressure, the activity of ALP increased significantly, and the expression of collagen type I was positive. In the treatment group, the mRNA expression of OPG increased significantly （P〈0.05） and the mRNA expression of OPGL decreased significantly （P〈0.05） after 2 weeks, compared with the control. Conclusion： Intermittent negative pressure could promote osteogenesis in human BMSCs in vitro.

Osteogenic potential of rabbit marrow stromal stem cells cultured in vitro: a hi stochemical and scanning electron microscopic study

To further investigate the osteogen ic potential of rabbit marrow stromal stem cells cultured in vitro. Methods: Rabbit marrow stromal stem cells were isolated by dens ity gradient centrifugation method and amplified in the flasks, using the osteog enic inducing conditions (OGC) as the culture media. The osteogenic potential of marrow stromal stem cells were investigated by means of bone seeking fluoresce nce (tetracycline) labelling, Alizarin red S (ARS) staining, Alcian blue Sirius red (AS) staining, and scanning electron microscope. Results: After being passaged, the marrow stromal stem cells in creased in number, became confluent and formed multi layer structure. The strom al stem cells excreted innumerable tiny granules, heaping up on the cell body an d merging gradually into foggy substances. These foggy substances kept on enlarg ing and formed round, oval, or flake like nodules. These nodules revealed brigh t golden yellow fluorescence under fluorescence microscope when labelled with te tracycline. Histochemical study with specific new bone staining with ARS reveale d positive calcium reaction, both denoting that they were newly formed bone tiss ues. After they were stained with AS, collagen and acid mucopolysaccharide were shown. Under scanning electron microscope, three types of cells with different c onfigurations were found. They were globular cells, spindle shaped cells and po lygonal or polygonal cells. Granules were excreted from the cells and heaped up on the cell body. Needle shaped and irregularly rectangular crystals also appea red and agglomerated with the granules to form nodules and trabecula like or fl ake like structures.Conclusions: Sequence of events of bone formation by rabbit mar row stromal stem cells cultured in vitro is fully depicted and confirmed, which provides the foundation for further investigating the mechanisms of osteoblast d ifferentiation from marrow stromal stem cells and the possible application in or thopaedics.

背负乡村的希望——走近2011年度安徽省优秀乡村教师(之一)

郑守国,男,生于1963年4月;中共党员;教龄29年。个人简历:1982年8月至今,定远县观寺小学,教师、校长。于邦友,男,生于1965年3月;中共党员;教龄28年。个人简历:1983年9月至1993年7月,固镇县浍北中学,教师;1993年9月至今。

Effects of insulin-like growth factor-1 on the properties of mesenchymal stem cells in vitro

Objective:To explore the effects of insulin-like growth factor-1(IGF-1) on migration,proliferation and differentiation of mesenchymal stem cells(MSCs).Methods:MSCs were obtained from Sprague-Dawley rats by a combination of gradient centrifugation and cell culture techniques and treated with IGF-1 at concentrations of 5-20 ng/ml.Proliferation of MSCs was determined as the mean doubling time.Expression of CXC chemokine receptor 4(CXCR4) and migration property were determined by flow cytometry and transwell migration essay,respectively.mRNA expression of GATA-4 and collagen II was determined by reverse transcription-polymerase chain reaction(RT-PCR).Results:The mean doubling time of MSC proliferation was decreased,and the expression of CXCR4 on MSCs and migration of MSCs were increased by IGF-1,all in a dose-dependent manner,while the optimal concentration of IGF-1 on proliferation and migration was different.IGF-1 did not affect the expression of GATA-4 or collagen II mRNA.Conclusions:IGF-1 dose-dependently stimulated the proliferation of MSCs,upregulated the expression of CXCR4,and accelerated migration.There was no apparent differentiation of MSCs to cardiomyocytes or chondrocytes after culturing with IGF-1 alone.