| Myocardial infarction is one of the highest death morbidity in diseases of thecardiovascular system diseases. How to protect the infarction area surrounding ischemicmyocardial cells, reduce scar formation, improve heart function and prevent heart failureafter myocardial infarction is an important subject in the study of cardiovascular disease.Tβ4is a small peptide composed by43amino acids, which is highly conserved inspecies and widely distributed in most of the cells excent the red blood cells. It participatesin many important life activities involved in the human body and can not only promotewound healing, hair growth, tissue repair and angiogenesis, but also has anti-inflammatoryeffect and endotoxin shock. Meanwhile, it can maintain the dynamic balance ofcytoskeleton. The current study of Tβ4has entered the stage of clinical trials for a varietyof traumatic disease and cardiac protection after myocardial infarction.Tβ4used at this stage derives from chemical synthesis. Peptide synthesis of43amino acids is low in efficiency, high in the cost, has serious environmental pollution, and highlyrestrictive in mass production. The genetic engineering products of Tβ4are difficult topurify because of its smaller molecules. In the early stage of the study, we produced Tβ4dimer protein by using engineering method, which overcome the defects of hardness toexpress by the chemical synthesis of molecular peptides. At the same time, it set up theone step of the Tβ4dimer protein purification method, which improved the massproduction process. The preparation and purification methods get two Chinese utilitypatents（ZL200810232709.9；ZL201110376361.2）The research of Tβ4dimer proteinpromoting wound healing function have obtained major funding of the national drugdiscovery research（2011ZXJ09104-01）.On the basis of the above, the subject researchwill further study the cardiac protection effect on Tβ4dimer protein after myocardialinfarction, and discuss its mechanism, so as to lay a good foundation for extending theindication of the genetic engineering drugs.We explore our study through crystal violet staining, scratch assay, tube formation,flow cytometry and confocal laser experiments to test the biological activity of Tβ4②, andthrough the mouse model of myocardial infarction to indentiry the cardioprotection ofTβ4②, and we use qPCR to explore the mechanism of Tβ4②.Through the experiment ofscratch test, the research proved that Tβ4can promote the migration of HUVECs. It hasestablished that Tβ4②can improve the endothelial cells of blood vessels forming by tubeformation assay; By confocal laser experiments, it confirmed that Tβ4②can inhibitcardiac fibroblasts secrete collagen; By flow cytometry, it confirmed that Tβ4②caninhibit myocardial apoptosis induced by hypoxia. By building the myocardial infarctionmodel in mice, it confirmed that Tβ4②can increase vascular density on the edge of theinfarction area, reduce the infarction area, control the myocardial hypertrophy andimprove heart function. By qPCR, it confirmed that Tβ4②can raise the mRNA’sexpressed level of Angiopoietin-2, CCR2, CCR3genes. And in the above experiments, thebiological activity of Tβ4dimer is greater than the monomer. To sum up, these resultssuggest that Tβ4dimer we purified by engineering method have obvious cardioprotectiveeffects, thus to lay a foundation for Tβ4dimer can be used as a cardioprotective durg aftermyocardial infarction. |
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