OBJECTIVE: To present the functional, immunocytochemical and histopathologic results (in vitro or in heart specimens) after isolation, culture and co-culture of mesenchymal stem cells and skeletal myoblast cells transplanted and co-transplanted in experimental animals with ischemic heart disease and left ventricular ejection fractions lower than 40%. METHOD: We utilized 72 Wistar rats, divided into four groups according to the culture media or injected cells: control group into which only culture media was injected (22 rats); mesenchymal stem cell group (17 rats); myoblast skeletal cell group (16 rats) and co-culture group (17 rats). In the immunohistochemical studies, the cells were stained with anti-vimentin, anti-desmin and anti-myosin. In the histopathologic analysis, slides were stained with Gomori Trichrome, and neo-vessels and muscle tissues were identified. In the functional analysis the left ventricle ejection fraction was analyzed one week after myocardial infarction and one month after the injection. RESULTS: The initial left ventricle ejection fraction (control echo) was not statistically significant between the four groups (P=0.276), but was significantly different in the follow-up examination (P=0.001). This difference was seen between the control and the myoblast skeletal cells groups (P=0.037), between the control and the co-culture groups (P<0.001), and between the mesenchymal stem cell and co-culture groups (P=0.025). When the initial and final echocardiograms in each group were compared, the control group deteriorated (P=0.005) and the co-culture group improved (P=0.006). With the immunocytochemical in vitro analysis, mesenchymal stem cells were identified when stained with anti-vimentin and muscle cells when stained with anti-desmin. In the heart specimens, muscle tissue, stained with anti-desmin and skeletal myoblasts cells, stained with fast anti-miosin were identified. In the histopathologic analysis, new vessels were observed in the mesenchymal stem cell and skeletal myoblast groups, and muscular tissue, angiogenesis and myogenesis in the co-culture group. CONCLUSION: The left ventricle ejection fraction improved in the group in which muscle cells were injected and more strikingly in the co-culture group. The immunohistochemical findings in the culture and co-culture groups evidenced the corresponding cells. In the heart specimens, muscle and skeletal myoblast cells were found. In the histopathologic examination, new vessels and muscle tissue were found in the mesenchymal stem cell, skeletal myoblast cell and co-culture groups.
Cell transplantation; Myocardial infarction; Myocardium; Myocardial ischemia; Cell culture
