Study Of The Differentiation And Effect Mechanisms Of Cardiac Myosin Specific-T Lymphocytes In Myocardial Immune Reaction

Part IStudy of the differentiation and effect mechanisms of cardiac myosinspecific-T lymphocytes in myocardial inflammationObjective To observe myocardial injury and inflammation of recipient rats which were adoptivly transferred cardiac myosin-specific Th cells, explore which type Th cells participate in the process, and clarify the immune mechanisms of myocardial injury after acute myocardial infarction (AMI).Methods Cardiac myosin-specific Th1 or Th2 cells were generated in vitro by coculturing rat Th cells and dendritic cells in the presence of cardiac myosin and polarizing cytokines for 16 days. Unactivated T lymphocytes served as controls. Th1, Th2 or unactivated T cells were transferred into naive syngeneic rats by a single tail vein infusion. These three groups (Th1-group, Th2-group and control group) of recipient rats were killed at 3 days, 1, 4 and 8 weeks after cell transfusion to study myocardial inflammation. Lymphocytes infiltration in the myocardium was evaluated by hematoxylin-eosin staining. In addition, mRNA and protein levels of pro-inflammatory cytokines including interleukin (IL)- 1β, IL-6 and tumor necrosis factor (TNF)-a in myocardial tissue were determined by RT-PCR and immunohistochemistry respectively.Results While the myocardium of the controls remained normal at all selected time points, in the Th1-group lymphocytes infiltrated at 3 days, peaked at 1 week, decreased rapidly at 4 weeks and returned to its basal level at 8 weeks. In addition, mRNA and protein levels of all pro-inflammatory cytokines demonstrated same dynamic change as lymphocytes infiltration in the Th1-group. However, there was no significant differencein inflammation between the Th2 and control groups.Conclusion Cardiac myosin specific-Th1 cells can induce lymphocytes infiltration andthe expression of pro-inflammatory cytokines in myocardium and then drive myocardialinflammation.Part IIStudy of the differentiation and effect mechanisms of cardiac myosin specific-T lymphocytes in myocardial remodelingObjective To observe myocardial remodeling of recipient rats after adoptivly transferring cardiac myosin-specific Th cells, explore which type Th cells participate in the process, and clarify the immune mechanisms of myocardial remodeling after AMI. Methods Cardiac myosin-specific Th1 or Th2 cells were generated in vitro by coculturing rat Th cells and dendritic cells in the presence of cardiac myosin and polarizing cytokines for 16 days. Unactivated T lymphocytes served as controls. Th1, Th2 or unactivated T cells were transferred into naive syngeneic rats by a single tail vein infusion. These three groups (Th1-group, Th2-group and control group) of recipient rats were killed at 3 days, 1, 4 and 8 weeks after cell transfusion to study myocardial remodeling. The levels of α-myosin heavy chain(MHC), β-MHC, matrix metalloproteina-se(MMP)-2 and tissue matrix metalloproteinase inhibitor(TIMP)-2 mRNA were determined by RT-PCR. Cadiocyte apoptosis was detected by TUNEL method. In addition, ventricular function was evaluated by echocardiography and hemodynamics analysis.Results Myocardial remodeling was observed in Th1 group: (1) α- MHC mRNA was decreased while β-MHC mRNA was increased at 4 and 8 weeks; (2)The levels of MMP-2 were significantly increased at 1 week and 4 weeks while the levels of TIMP-2 were elevated at 4 weeks and 8 weeks; (3)Cadiocyte apoptosis was detected at all time points and it was more obvious at 1 week and 4 weeks; (4)Hemodyamics analysis showed left ventricle pressure maximal rate of rise and fall (±dp/dtmax) noticeably decreased 1 week later. However, there was no significant difference in myocardial remodeling between the Th2 and control groups.Conclusion Cardiac myosin specific-Th1 cells can up-regulate the levels of MMP-2, induce the rexpression of fatal genes and cadiocyte apoptosis in myocardium and then drive myocardial remodeling. This may be associated with myocardial inflammation.