| Collagen is widely distributed in animals'connective tissue, it can maintain the normal physiological (?)unctions of cells,tissues and organs, and it have an important role in wound repair. Collagen under certain external conditions could be hydrolysis and the product is Collagen peptide. Collagen and collagen peptide is no trict distinction between the two, but the difference between the length of the peptide chain, in the past they ave called collagen.Collagen and collagen peptide involved in cell differentiation and proliferation, it can nake bone, tendon and skin with mechanical strength; because of its rich in a lot of hydrophilic groups so it has good moisture retention, and because of collagen peptide Biological compatibility so it has many use a wide ange of medical and health fields, such as beauty again, trauma, orthopedic, burn, tissue repair, and so on. Currently the production of collagen is the major acid, alkaline solution extracted from animal connective tissue, he extraction process more or less loss of biological activity, applied to the human body will produce allograft ejection or heterogeneous, and there is very large virus risk. With the rapid development of molecular biology, nany scholars in order to take advantage of the excellent performance of collagen, while avoiding high-risk (?)iruses of animal origin, began to use genetic engineering technology, choose a variety of host cells to produce ecombinant human collagen. However, because structure, composition, functions and distribution of collagen, t makes its expression in prokaryotic cells become very difficult. However, prokaryotic expression systems ompared with other expression systems, E. coil as a host has mangy adavantages, such as genetic background 'clear, simple technology, simple culture conditions, large-scale fermentation of low cost, rapid rapid eproduction and growth short short cycle, this study used E. coli expression system system, the use of genetic ngineering the production of collagen peptides.Surface of the Earth, ultraviolet radiation includied UVA and UVB.UVB mainly cause burns and skin ancer, UVA is closely related to skin aging. Because a high incidence of skin cancer, so more research on iltraviolet B in abroad, and most of China's population belongs to skin typeâ…£-type, skin cancer incidence rate very low, with a special focus on the practical significance is VUA rather than UVB. We choose the ong-wave ultraviolet (UVA) radiation as the object of study.In this study, we reported the cloning and over-expression of a gene encoding human collagen ieptide(CW-CP6) in Escherichia coli and the establishment of a purification protocol for obtaining the (?)combinant protein. The collagen peptide (CW-CP6) had a molecular weight of about 46 kDa, and CW-CP6 xpression comprised approximately 10% of the total bacterial protein expression. Sodium dodecyl sulfate olyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that most of the collagen peptide(CW-CP6) xisted in the soluble fractions. Purified collagen peptide (CW-CP6) was highly soluble. We performed assays with the MTT,annexin V-FITC/PI and Tunel to investigate the cytoprotective effects of CW-CP6 on the roliferation of UVA-damaged human skin fibroblasts cells and the spontaneously immortalized human eratinocyte cell line HaCaT. Rradiation dosages (5 J/cm2) significantly decreased the proliferation activities of luman Skin Fibroblasts cells and the spontaneously immortalized human keratinocyte cell line HaCaT. Compared with UVA irradiated group, in the given concentration, CW-CP6 could improve the activities of cell's roliferation(P<0.05) and decrease the apoptosis rate of cell significantly (P<0.01). UVA can damage the Human kin Fibroblasts cell and the spontaneously immortalized human keratinocyte cell line HaCaT in vitro. The (?)W-CP6 has protective effects on HSF and HaCaT irradiated by UVA, the mechanism of this effect may be associated with it's anti-oxidative effect and enhancing cell's proliferation.
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