Liquid Type I Collagen In The Construction Of Cardiac Tissue Engineering Research

BackgroundIschemic heart disease and Dilated Cardiomyopathy followed by heart failure represents one of the major causes of morbidity and mortality. The human heart can not regenerate significantly because adult cardiomyocytes are terminally differentiated and can not replicate after injury. The loss of cardiomyocytes accounts for a decrease in myocardial function which leads to total heart failure. Conservative treatment of heart has focused on reduction of work load and protection from human factors and has little therapeutical effect on patients in end-stage heart failure. Heart transplantation represents a life-saving and life-expanding treatment modality for end-stage heart failure. Although advances in surgical techniques, the shortage of donor organs has limited the heart transplantation and induced researchers effort to develop alternative approaches. One strategy is the in vitro engineering of myocardial tissue. It supplies a new strategy to cope with heart failure in the future. Because the constructs of heart is very complicate and the myocardium tissue has high machine compliance, the materials for myocardial tissue engineering should have more characteristic. Some studies showed that cells could growth in both collage sponge and liquid collage type I.AIMS (1)To explore the biocompability of collagen sponge and liquid collagen type I with rat myocardium-like cells from bone marrow mesenchymal stem cells (BMMSCs) for myocardium tissue engineering.(2)Construction of liquid type I collagen material for myocardial tissue.METHODS(1)The collage sponge and liquid collagen type I was made up respectively. SD rats (1 month) were killed by decapitation according to the guidelines for the care and use of laboratory animals. The rat's limbs were isolated and degermed. Removed limbs'muscles and exposed the bones. Use the culture medium (Dulbecco's Modified Eagle's Medium, DMEM) to flush bone marrow cavity repeatedly until the bone marrow cavity clean. Total mononuelear cells were isolated from rat bone Marrow by density gradient centrifugation. Then the cells were plated on culture dishes in Incubators. BMMSCs generated to third, then cells were incubated with a final concentration of 10μmol/L of 5-azacytidine (5-aza) 24-hour. Induced cells were called myocardium-like cell and identification with troponin I(cTnI). The in vitro cultured myocardium-like cells were compounded to collagen sponge and collagen type I respectively, followed by the culture for 7 days . Samples were obtained at 1, 3, 5, 7 days of culture , the morphology and adhesion of myocardium-like cells were observed under scanning electron microscope and hematoxylin-eosine(HE) dyeing; the proliferation of myocardium-like cells was detected by MTT method.(2) Myocardial cells and liquid type I collagen in the electrical stimulation under construction myocardial tissue engineering. It will be liquid collagen and myocardial cells to self-cultivation of electrical stimulation training in the small room every day with pulsed electrical fields 10 V, pulse widths 0.3ms, and pulse frequencies from 2Hz electrical stimulation of six hours. Under the microscope after stimulation of cell growth patterns, availability and proliferation of contraction. A total of 15 days.RESULTS (1)The myocardium-like cells on the liquid collagen type I adhered and grew better than those on collagen sponge. At 1, 3, 5, 7 days of culture, the myocardium-like OD value increased significantly on temperature sensitive collagen type I materials compared with those on collagen sponge materials (P<0.01).(2) In the fields 10 V, pulse widths 0.3ms, and pulse frequencies from 2Hz electrical stimulation, cardiac-like tissue engineering Compared with the control group, cell proliferation without significant changes, no significant contraction.CONCLUSIONBMMSCs with 5-aza can be induced positive cardiac troponin I cells.The biocompability of temperature-sensitive collagen type I with myocardium-like cells is better than collagen sponge, so temperature-sensitive collagen type I material is an ideal material for myocardium tissue engineering. Frequency of 2 Hz, for wide-0.3 ms, the rate for the 10 v electrical stimulation of the cardiac-like tissue engineering no obvious effects.