| Objective The prevalence of cardiovascular disease in China is increasing,and the traditional treatment methods are not satisfactory.Therefore,people continue to explore new treatment methods.With the extensive research of tissue engineering technology and stem cell transplantation technology in recent years,it provides a new idea for the therapy of cardiovascular diseases,but there are still some obstacles,such as low survival rate and cell retention,difficulty to differentiate into cardiomyocytes,which seriously reduces the therapeutic effect of stem cells after transplantation.Hence,it is an urgent problem to improve the survival rate and retention rate after cell transplantation.This research is based on 3D gelatin microspheres,composite adipose derived stem cells,construction of cardiac tissue engineering micro-unit,to investigate the therapeutic effect of cardiac tissue engineering micro-unit on myocardial infarction in rats,and to provide new ideas and feasible experimental basis for further development of stem cell transplantation technology.Method In vitro analysis of pore and particle size of 3D gelatin microspheres by scanning electron microscope.Adipose derived stem cells were isolated from neonatal SD rats,and their immunophenotype and multidifferentiation ability were identified by flow cytometry,adipogenesis,osteogenesis and chondrogenesis.The tissue engineering micro-unit was prepared by co-culture of the 3D gelatin microspheres and adipose derived stem cells,FDA/PI staining was performed in cultured 1d,4d and 7d,and the growth and survival of cells in the microspheres were observed under laser confocal microscopy,the proliferation effect of 3D gelatin microspheres on adipose derived stem cells was detected by CCK-8.Finally,the SD rat model of acute myocardial infarction was constructed,and the cardiac tissue engineering micro-unit was injected into the myocardial infarct site,and the PKH-26 was used to trace the outcome of the injection of adipose derived stem cells into the infarcted area.After 4 weeks,the effect of cardiac tissue engineering micro-unit was evaluated by echocardiography,masson staining.Result Under the scanning electron microscope,the average diameter of the microspheres is about 200 um and the aperture is about 16 um.The adipose derived stem cells were successfully isolated in vitro and detected by flow cytometry with a purity of more than 95%(CD29/CD90 positive,CD34/CD45 negative).Laser confocal microscopy revealed that the number of living cells in 3D gelatin microspheres was increased gradually after 1d,4d and 7d,and CCK8 assay also found that 3D gelatin microspheres could promote cell proliferation.Compared with the control group,the left ventricular ejection fraction of rats in the cardiac tissue engineering micro-unit group improved by 17%,and masson staining found that the fibrosis area decreased in the infarct area.Conclusion The 3D gelatin microspheres have good three-dimensional spatial structure,which can increase the survival rate after cell transplantation and promote the adhesion,proliferation and secretion of adipose derived stem cells.The cardiac tissue engineering micro-unit constructed by the combination of 3D gelatin microspheres and adipose stem cells was effective in the treatment of myocardial infarction in rats,and the repair of cardiac tissue was achieved successfully.The combination of gelatin microspheres and seed cells to construct a micro-unit with good biological function provides a new idea for tissue engineering cardiac repair. |
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