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Objective To integrate existing data and analyze the optogenetic application in the study of the cocaine addiction mechanism.Methods The key words optogenetics,addiction, cocaine and so on were selected.Relevant research information was collected from various authentic databases such as China Journal Full-text Database,Chinese Biomedical Databases,Wanfang Digital Journals,VIP Full-text Database and PubMed,SCIENCEDIRECT,SPRINGERLINK databases by literature study,assess the quality of the studies and the qualitative systematic review was conducted in this study.Results Findings from present data showed that:with great spatial and temporal specificity,the optogenetic application not only proved the important role of traditional theories of mesolimbic dopamine system,but also dissected the neural circuits and molecular mechanisms of dopaminergic and glutamatergic neurotransmission underlying cocaine addiction.Conclusion The use of optogenetic tools has given researchers the potential to dissect the neuronal circuits and molecular changes,leading us to a better understanding of the mechanisms of cocaine addiction and to the development of novel treatment.
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BACKGROUND: Growth differentiation factor-5 (GDF-5) plays an important role in the development and formation of cartilage, extremities, and joints, which is a widely used joint development marker.OBJECTIVE: To express mature peptide of human GDF-5 in E. coil by the way of genetic engineering, and to explore the inductive activity of recombinant protein in vivo.DESIGN, TIME AND SETTING: The observation experiment based on gene was performed at the Analysis and Testing Center of Southern Medical University from January to June 2006.MATERIALS: Human fetus cartilage tissue was harvested from Department of Gynaecology and Obstetrics, and the consent was obtained from the family. Ten KM mice were purchased from experimental animal center of Southern Medical University, half male and half female, weighing 18-22 g, aged 6-8 weeks.METHODS: The hGDF-5 gene encoding mature peptide was gained by RT-PCR from the total RNA which was extracted from fetus cartilage tissues, and was inserted into the pET22b(+) vector to construct recombinant prokaryotic expression plasmid pET22b(+)-GDF5, which was transformed into E. coil BL-21 to be expressed after IPTG induction. Proteins of interest were purified with sepharose chelated with nickel ions (Ni2+) and then implanted in mouse hindlimb muscle to evaluate the biological activities by routine hematoxylin-eosin staining.MAIN OUTCOME MEASURES: The expression, sequencing of target gene was observed by agarose gel electrophoresis, and the protein expression was detected by SDS-PAGE electrophoresis, meanwhile, the GDF5-inducing activity was evaluate by histological observation.RESULTS: RT-PCR product was about 350 bp in length, which was confirmed by double enzyme digestion of the recombinant plasmid, sequencing result was in agreement with the reported hGDF-5 sequence in Genbank. SDS-PAGE analysis showed a conspicuous band representing a new foreign protein with relative molecular mass of approximately 14 KD after induced expressioin. Cartilage tissues were formed in the mouse muscle where the purified proteins were implanted. CONCLUSION: The integral human GDF-5 mature peptide gene was cloned successfully from human fetus cartilage tissue and a high-yield expression was achieved in E. coli, the pudfied protein has chondrogenic activities in vivo.
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Objective To investigate the effects of gene transfection with human growth/differentiation factor 5(GDF5)on the growth and difierentiation of bone nlarrow stromal stem cells (BMSCs).Methods GDF5 gene was trans fected into BMSCs by liposome method. Then cell proliferation and cycles were examined by MTT and flow cytometry respectively. Cell morphology was observed under light microscope and electron microscope (EM).GDF5 and Collagen Ⅱ were detected at the level of mRNA and protein by RT-PCR and immunocytochemistry. Alkaline phosphate activity was examined by lead citrate method. Osteocalcin mRNA expression was determined bv RT-PCR. ResulIs GDF5 gene was transfected into BMSCs successfully and the transfected cells still maintained their natural growth and proliferation features. Stable expression of GDF5 gene in BMSCs was obtained. The trans fected ceils had basically the same proliferation ability and cell cycles as the untransfccted ones. After transfection comparatively more polygonal cells could be seen in light microscope, showing irregular arrangement mode. Plenty organells were observed and cell nucleus showed irregular shape under EM. The expressions of Collagen Ⅱ mRNA and protein were positive. But osteocalcin mRNA expression was negative. Conclusion Since BMSCs can be induced by GDF5 to differentiate into chondrogenic cells. GDF5 gene-modified BMSCs may be used as candidate seed cells of cartilage tissue engineering.