| Objective To explore the method for isolation and cultivation of adipose tissue-derived mesenchymal stem cells (ADMSCs), prove that ADMSCs can be differentiated into cadiomyocyte, and confirm that ADMSCs can survived in vivo and improve heart function after myocardial infarction in canines, and investigate its the mechanism. We hope to find a new source of cellular cardiomyoplasty and provide experimental foundation for ADMSCs transplantation for treating congestive heart failure after myocardial infarction.Methods (1) Isolating, culturing and determinatiing ADMSCs. The abdominal hypodermic adipose tissue of canines was isolated and cultured by the method of digesting and adhering to the culture flask. The cells of third passage were taken to determine CD44, HLA-DR, factorâ…§with immunocytochemistry method, with phosphate buffer solution (PBS) as blank control. (2) Induced ADMSCs in vitro. The cells of third passage were induced by 5-aza. On the 7th, 14th, 21st, 28th day, immunocytochemistry was used to determine the cardiac phenotype. (3) Treatment heart failure after myocardial infarction with ADMSCs transplantation. Canines were randomly divided into three groups, ADMSCs implantation group, induced ADMSCs implantation group and control group, which received IMDM medium, ADMSCs which marked by DAPI and induced ADMSCs which marked by DAPI through intramyocardial injection, respectively. To test heart function change, UCG was measured in each group before the surgery, 1 and 4 weeks after the surgery and haemodynamics was test at 4 week. 4 weeks later immunofluorescence was given observe the information of the transplanted cells survival and differentiation. After MI and cell transplantation for 4 weeks HE staining, immunohistochemical, capillary densities, collagenvolume fraction and apoptosis cell population studied.Result (1) There was a large amount of mesenchymal stem cells in canines adipose tissue. Immunocytochemical staining showed that most of cultured cells were CD44 positive, HLA-DR, factor Vffl negative. (2) Induced cells became bigger and longer. The connection of the cells was formed. The direction of cell arraying was gradually similar. The cells were stained positively for Troponin T. (3) Surviving ADMSCs and induced ADMSCs were identified by DAPI positive spots in border of infarcted region and transdifferentiated into cardiomyocytes characterized with a positive cardiac phenotype(troponin T) 4 weeks after transplantation. LVESV of ADMSCs transplantation group and indused ADMSCs transplantation group were lower than control group, whereas LVEF^ LVSP and +dp/dtmax were significantly higher. But -dp/dU LVEDP and LVEDV of ADMSCs transplantation group were all lower than control group and indused ADMSCs transplantation group. Left ventricle ponderal index, capillary densities and collagen volume fraction in infarction zone were increased by ADMSCs transplantation and induced ADMSCs transplantation, and collagen volume fraction in noninfarction zone and apoptosis cell population were decreased. Moreover, ADMSCs implantation revealed that there was a marked increase in number of visible collateral vessels than induced ADMSCs. And ADMSCs implantation reduced apoptosis cell population, the extent of which was more than that seen with induced ADMSCs.Conclusion Canines adipose tissue contains mesenchymal stem cells, and ADMSCs may differentiate into cardiomyocytes. After ADMSCs transplanted into the canines, the cells can suviving and differentiate into myocardial cells. Furthermore they can improve heart function after myocardial infarction in canines and the possible reason may be correlate with microenvironment and produce a marked effect by angiogenesis, inhibition apoptosis and reduction collogen deposition in noninfraction zone.
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