Bone marrow stromal stem cells have been used in cartilage tissue engineering for nearly 20 years. This has been a key focus in stem cell research. This article serves to review application, progress and facing problems of bone marrow mesenchymal stem cells (BMSCs) in cartilage tissue engineering by retrieving publications. With the development of molecular biology, biomaterial, computer and nano-biotechnology, tissue-engineered cartilage constructed with BMSCs as seed cells combined with biomaterial stent has a widely application perspective in repairing articular cartilage defect.

BACKGROUND: To understand mechanism, biological property and morphological component of nanometer bone material and discuss present status and applied prospect.DATA SOURCES: A computer-based online search of Medline database was undertaken to identify articles about mechanism, biological property and morphological component of nanometer bone material in English from January 1966 to February 2006, and the key works were novel bioactive materials and bone tissue engineering; meanwhile, Chinese relevant articles were retrieved in Chinese in Tsinghua database from January 2001 toOctober 2004, and the key words were nanometer bone and clinical application.STUDY SELECTION: Articles in disposal group and control group were retrieved firstly. Those obviously non-random and repetitive researches were excluded. Full text of the rest articles was looked up finally.DATA EXTRACTION: Tlere were 124 articles about mechanism, biological property and morphological component of nanometer bone material. Among them, 27 experiments or clinical researches were included.DATA SYNTHESIS: Nanometer bone has favorable conductibility and induction of bone; meanwhile, it is characterized by human-like grading structure and multi-well structure of rangu, favorable biocompatibility and stable biodegradation.Nanometer bone material also can be used in confluence of vertebral body, the buccal surgery fields, the gene therapy of uncompleted osteogenesis, rheumatic arthritis (RA) and malignant tumor. Nanometer bone material is tendency to perfection through improvement of technology.CONCLUSION: Nanometer bone material with many particular properties overcomes many difficulties and achieves a satisfactory effect at clinical pilot phase.

OBJECTIVE: The interrelationship between various growth factors and chondrocytic regeneration has drawn the attentions of scholars and the study on growth factors and repair of articular cartilage defects has been carried on to summarize the latest progression of transforming growth factor-β (TGF-β) in articular cartilage repair so as to provide theoretical evidence for its application in cartilage histoengineering.DATA SOURCES: The relevant papers about studies on mechanism and types of articular cartilage injury, TGF-β and interrelationship between TGF-β and articular cartilage repair were looked up on http:∥www.ncbi.nlm. nih.gov/PubMed from January 1995 to December 2004. The retrieval words were "TGF-β, articular cartilage" limited only in English version.The relevant papers about studies on TGF-β and articular cartilage repair were also looked up on http:∥www.zglckf. com and linked database from January 1999 to December 2004, with the retrieval words of "TGF-β, articular cartilage" limited only in English version.STUDY SELECTION: During the initial evaluation of data and after looking up the quotation of each paper, the inclusive criteria were determined as follows: the paper should be relevant with TGF-β repair of articular cartilage injury; and the exclusive criteria: repeated research and Meta analysis papers. The papers that had not been excluded applied randomized design, control and blind comparison.DATA EXTRACTION: Altogether 95 papers were collected on TGF-βand TGF-β repair of articular cartilage injury, of which, 15 papers were in conformity of inclusive criteria, 56 papers were excluded due to dated research and 24 papers were due to repeated research. Of 15 papers, 3 papers were on the mechanism and types of articular cartilage injury, 6 papers were on biological function of TGF-β and 6 papers were on TGF-βand TGF-β repair of articular cartilage injury.pact, cut, torsion and friction, which is beyond the physiological endurance of articular cartilage. Articular cartilage defects are divided into defects of partial thickness and entire layer of cartilage. The auto-repair growth factor with various functions, which is produced by either autocrine or paracrine. It starts transmitting information by integrating with lagen and stromatin by irritating osteocytes and chondrocytes to form rapidly extracellular matrix so as to promote repair of bone and cartilage injury.CONCLUSION: TGF-β plays the importance in histoengineering repair of articular cartilage injury. By bringing induction of cartilage into play,TGF-β promotes differentiation of stem cells into cartilage or enhances specific matrix synthesis of cartilage, such as collagen Ⅱ and proteoglycan. Due to the limitation of various repair methods of cartilage defects at present, being a cell factor with good cartilage induction, TGF-βwill present extensive prospects in the application of cartilage histoengineering.

Objective: To construct a recombinant lentivirus harboring RNAi sequence targeting rat nogo receptor gene and to observe its infection efficiency of 293T cells. Methods: Lentivirus shuttle plasmid containing siNgR199 cDNA was constructed by gene engineering and was used to transfect 293T cells in the presence of packaging plasmids. Forty-eight hours later the supernatant was collected and the titer of virus was determined. The recombinant lentivirus and the standard lentivirus were used to transfect 293T cells at 1 MOI,3 MOI,5 MOI,10 MOI and 20 MOI. Polymerase chain reaction (PCR) was used to detect the recombinant vector; enhanced green fluorescent protein (EGFP) expression was used to determine the titer and the infection rate of the recombinant lentivirus under fluorescent microscope. Results: Restriction endonuclease and PCR analysis confirmed that the siNgR199 cDNA was successfully inserted into the lentivirus vector. The titer of the recombinant lentivirus harboring siNgR199 was 1×108 ifu/ ml and the best MOI was 3. Conclusion: The recombinant lentivirus containing siNgR199 gene has been successfully constructed, which lays a foundation for future axon regeneration in treatment of spinal cord injury.

Objective To investigate the effects of cobalt chloride(COCl2)induced rat alveolar epithelial cell apoptosis and the significance of related apoptosis protein hypoxia inducible factor-lalpha(HIF-1 a)expression. Methods Alveolar epithelial cells were cultured in vitro and divided into four groups with 6 samples in each.Hypoxia 4 h group:added 500μmol/L COCl2 for 4 hours inducing alveolar epithelial cell hypoxia;hypoxia 24 h group:co-cultured with COCl2 for 24 hours;hypoxia 48 h group:co-cultured with CoCl2 for 48 hours;control group:no CoCl2 added.The apoptosis rates were detected by fluorescent microscope and flow cytometry.The apoptosis morphological changes of the cell were observed by transmission electron microscopy.The protein expression of HIF-la was detected bv Western Blot. Results (1)Fluorescent microscope results showed that apoptosis rate in hypoxia 4 h、24 h、48 h group[(5.83±0.76)%,(15.00±3.28)%and(51.50±3.00)%],were higher than control group[(1.50±0.50)%](P＜0.05).(2)Flow cytometry analysis reached the same results as with fluorescent microscope.(3)Typical morphological changes of apoptosis were observed in hypoxia 24 h group.(4)HIF-1α expression in hypoxia 4 h、24 h and 48 h groups[0.69±0.035,1.02±0.044 and 0.71±0.046],were higher than control group(0.21±0.026)(P＜0.01).(5)Positive correlations were found between relative amount of HIF-1αprotein and apoptosis rate by fluorescent microscope and flow cytometry analysis(r=0.484,P=0.016;r=0.713,P=0.009).Conclusions Hypoxia could induce apoptosis of alveolar epithelial cells,which may participate in the pathogenesis of hypoxia-induced lung injury.

Objective To assess the impact of pigment epithelium-derived factor(PEDF)on the proliferation and apoptosis of the glioma cells by detecting expression of apoptosis related proteins.Methods U87 cells were treated with PEDF(1000μg/ml,U87PEDF),or without PEDF(U87com0),cell proliferation assays were performed by MTT assay to test the effect of PEDF on proliferation of glioma cells;Apoptosis assays were performed by flow-cytometric analysis;Western-blot Was used for evaluating the expression of p16 protein.Results The induced inhibitony rates of glioma cells by PEDF were(54.29±0.62)% Compaxed with the control(t=2.63,P<0.05).The apoptosis assay showed that(21.84±0.36)% of PI- negative/annexin V-positive Was present in the U87 PEDF cells.The appoptosis was associated with the incteases of p16 protein(0.82±0.09)compared with tlle control(0.43±0.03,P<0.05).Conciusion PEDF may play a significant role in apoptosis regulation and proliferation of glioma cell accompanied with the increase of the p16 protein.

Objective To assess the impact of pigment epithelium-derived factor(PEDF) on the migration of the glioma cells.Methods PEDF(100 ng/ml)was added to U87 cells(U87PFDF),and VEGF of 0.25μg/ml was added to U87PEDF+VEGF while U87 cells as control(U87con).The cell migratory assav was used tbr evaluating its inhibitory migration rate of PEDF.Real time RT-PCR was used for evaluating the expression of Laminin-8 gene.Results The number of migratory cells was higher than those with added PEDF,and the inhibitory rate of migratory was 38% even in the presence of VEGF.Real time RT-PCR revealed that the mRNA expression levels of α4,β1,γl were(1.043±0.090),(0.823±0.012).(0.762±0.05) copy/μl,which were higher than those treated by PEDF(0.633±0.004),(0.442±0.005).(0.424±0.002)copy/μl,respectively (P＜0.05).Conclusion PEDF could decrease the migmtory capacity of the glioma cells even in the presence of VEGF because of the regulation of Laminin-8 in part.

Chromosome Disorders ; Chromosomes, Human, Pair 13 ; Humans ; Infant ; Male ; Trisomy ; Trisomy 13 Syndrome

Microglia are activated and involve in the pathological and physiological processes of early brain injury and delayed cerebral ischemia after subarachnoid hemorrhage, thus impact the outcome of patients. Numerous studies have shown that microglia have different typings, signaling pathways,and functions. Interference with microglial activation or reduction of cytotoxic metabolites is important for improving the prognosis of SAH patients.

MicroRNAs (miRs) play an important role in regulating diverse cellular processes.It has been reported that miRs are associated with the formation and maturation of erythrocytes, and the expression of globin genes at post-transcriptional level.Compared with normal human enrythrocytes, various miRs are altered in the patients with thalassemia.These changes also happen in the patients with diverse clinical manifestations.In this paper, we systematically summarized the recent progress about the expression dysregulation of miRs in β-thalassemia and their roles in regulating the levels of γ-globin and fetal hemoglobin.During β-like globin gene expression, miRs directly or indirectly regulate the levels of erythroid-specific transcription factors through post-transcriptional action, such as B-cell lymphoma 11A (BCL11A), myeloblastosis oncogene (MYB), specificity protein 1 (Sp1), Kruppel-like factor 3 (KLF3) and GATA1.These effects subsequently regulate the switch between γ-and β-globin gene expression and affect fetal hemoglobin production.Targeting miRs might be a novel therapeutic strategy for β-thalassmeia.