Aerobic Exercise Combined Intervention Of G-csf Mobilization Of Mi Rat Bmscs Homing Of Influence And Its Possible Mechanism

Objective:This paper is to explore the impact and mechanism of aerobic exercise and G-CSF intervene on the mobilization and homing of bone marrow stem cell in myocardial infarction rats.Method:SD male rats,3months old, are randomly divided into8groups, each12: normal control group(group N), myocardial infarction group(group MI), myocardial infarction with aerobic exercise group(group ME), myocardial infarction with mobilization group(group MG), myocardial infarction with exercise training and mobilization group(group MGE), myocardial infarction with blocker and mobilization group(group MAG), myocardial infarction with blocker and exercise training group(group MAE) and myocardial infarction with blocker, mobilization and exercise group(group MAGE). The rats of group ME, MG, MGE, MAG, MGE and MAGE were all ligated their left anterior descending coronary to create the acute myocardial infarction model. Group MAE, MAG and MAGE rats were given AMD3100200μg/kg/12h1h after MI, continuous injected6d. Group MG, MAG and MAGE rats were given rhG-CSF10μg/kg/d3h after MI, continuous injected5d. Group ME, MGE, MAE and MAGE rats begin aerobic treadmill training after one week of MI, initial training speed is lOm/min, training time is10min, after rats adapt to incline, training intensity, time and speed gradually increased to16m/min by2m/min, exercise time was50min. Adaptive training treadmill was about5d, initial training time reduced to5min, other parameters are unchanged. In accordance with the training program, weekly training5d, continuous training8w. After8weeks, monitoring ECG, LVSP, LVEDP and±dp/dtmax and other indicators, made histologic section for HE and Masson specific staining method, observed the changes of cardiac structure and function of every group rats; Detecting the protein expression of HIF-1, MCP-1, SDF-1, CXCR4, CD29, CD34, CD44, CD90, c-kit and VLA-4by western blot and immunohistochemical methods.Result:1Results of heart coefficient showed:ECG showed:compared with group N, T wave voltage significantly reduced(p<0.01) in group MI and the HR increased; Compared with MI, the HR reduced, QRS and QT interphases significantly reduced (p<0.01) and T wave voltage significantly rise(p<0.01) in group ME, MG and MGE; Compared with ME, the T wave in MAE rise(p<0.05); Compared with MG, the HR of group MAG increased(p<0.05) and T wave voltage rise(p<0.01); Compared with MGE, QRS and QT interphases significantly reduced(p<0.01) and T wave voltage significantly rise(p<0.01) in MAGE. The dates of cardiac function showed:Compared with normal controls rats, LVSP and±p/dtmax significantly reduced(p<0.01), LVEDP significantly elevate(p<0.01) in group MI; Compared with MI group, the LVSP significantly rise(p<0.01), LVEDP significantly reduced (p<0.01),±dp/dtmax rise(p<0.05). In MI with aerobic exercise group, MI with mobilization group and MI with aerobics and mobilization group; Compared with ME, LVSP and±p/dtmax significantly rise(p<0.01) in group MAE; Compared with MG,+dp/dtmax(p<0.01) and-dp/dtmax significantly rise(p<0.05) in group MAG; Compared with MGE,±dp/dtmax significantly rise(p<0.01) in group MAGE.These show that MI badly damaged heart function, aerobic exercise and(or) mobilization intervention can significantly improve it, and the improvement of rat cardiac function of collaborative stem cell mobilization aerobic exercise is better than pure intervention factors. AMD3100could improve the cardiac function differed to the extent.2Histology observation shows:Masson showed:the cardiocytes of normal control group are aligned, and structure is normal; the myocardial cells of MI rats infracted myocardium are necrosis, appear alternative fibrosis; MI with aerobic exercise group and MI with mobilization rats infracted myocardium alternative fibrosis extent lighter, scar area decreasing, and part of the myocardial cell in MI with aerobic exercise group appears adaptability hypertrophy; In MI with aerobics and mobilization group, myocardial cells are arranged neat, scar area is less than pure aerobic exercise or mobilization intervention group. The degree of myocardial infarction were better in MAE and MAG than in ME and MG, the infracted area reduced and improved the cardiac remolding; the MAGE rat hearts could find more myocardial cell regeneration, only a very small collagen fiber existed, necrosis myocardium significantly reduced, the organization structure tend to be complete.These show that MI badly damaged the normal structure of heart, MI with aerobics and(or) with mobilization intervention can effectively improve MI structural change, and aerobic exercise collaborative stem cell mobilization have better effect. The infracted area reduced significantly and the number of cardiomyocyte increased after using AMD3100, it prompted that combined AMD3100play a certain role in myocardial infarction repair.3The Immunohistochemical results of chemotactic factor showed:In normal tissue, positive express particles is tan-yellow, MCP-1and HIF-1has less expression; In MI, HIF-1was more in infracted and the edge area; In MI with aerobic exercise group, MI with mobilization group and MI with mobilization and aerobics group, HIF-1positive particles significantly reduced and MCP-1increased, and HIF-1and MCP-1positive express of rats myocardial of MAG and MAE is more apparent, mainly express in myocardial cell and expression of HIF-1, MCP-1were more significantly increased in MAGE. WB results showed that compared with the normal control group, HIF-1expression increased, and reduced significantly in group ME, MG and,MGE(p<0.01). The expression of MCP-1increased in group MI, ME, MG and MGE(p<0.01). Compared with group ME, MCP-1and HIF-1increased in group MAE(p<0.01). Compared with group MG, MCP-1and HIF-1increased in group MAG(p<0.01). Compared with group MGE, MCP-1and HIF-1increased in group MAGE(p<0.01).The results indicated that, after myocardial infarction, organization blood was anoxic, which induced HIF-1expression increase, and prompted chemotactic factors MCP-1expression. Aerobic exercise and/or mobilization agent intervention could degrade HIF-1, repair infarction myocardial effectively and promote MCP-1expression; After using blockers AMD3100, HIF-1was gathered in cells, which could promote the formation of blood vessels and improve the metabolism, improve blood supply for ischemic heart muscle, and AMD3100also induced mononuclear cells, endothelial cells, macrophages, fibroblasts and smooth muscle cells secreted more MCP-1, and made chemotaxis more significant.4The expression of factors related with mobilization and homing of bone marrow stem cell. The Immunohistochemical results showed:In normal tissue, positive express particles is tan-yellow, SDF-1had rare expression CXCR4, CD44and VLA-4had less expression; After myocardial infarction, the expression of them increased; Compared with group MI, in MI with aerobic exercise group, MI with mobilization group and MI with mobilization and aerobics group, all of them positive particles significantly increased; AMD3100did not reduce expression of them. WB results showed that compared with the normal control group, CD44and VLA-4expression significantly increased in group MI(p<0.01); Compared with group MI, the expression of SDF-1increased significantly in group ME and MGE(p<0.01), the expression of CXCR4increased significantly in group MG(p<0.05) and MGE (p<0.01), the expression of CD44higher than group MGE(p<0.01), and VLA-4expressed more in group ME, MG and MGE. Compared with MG, CXCR4expressed more in group MAG, and expressed more in group MAGE than in group MGE. Compared with ME, CD44increased in group MAE(p<0.01). Compared with group MG, CD44increased in group MAG(p<0.01). Compared with group MG, VLA-4reduced in group MAGE(p<0.01).These showed SDF-1/CXCR4axis, CD44and VLA-4played an important role in the process that aerobic exercise and/or mobilization agent intervention improved the mobilization and homing of bone marrow stem cells after MI, however, the use of AMD3100did not weaken capability of the bone marrow stem cells homing to the damaged tissue. Indicated that aerobic exercise and/or G-CSF intervention may be involved in the repair process of myocardial infarction through activating myocardial stem cells or through other signaling pathways, in addition the dose of blocker also needs to be studied further.5The expression results of surface markers of bone marrow stem cell. The Immunohistochemical results showed:CD29, CD34, CD90and c-kit positive particles is tan-yellow, In normal tissue, they had rare expression. In MI group, the expression was increased in MI area and the edge area. In group ME and MG, positive particles are significantly increased, and positive expression of rats myocardial of group MGE, MAG, MAE and MAGE were more apparent, mainly expressed in myocardial appearance cell. WB results show:compared with the group MI, CD29expressed increased in group ME, MG and MGE(p<0.01), CD34and c-kit expressed more in group MGE(p<0.01), as well as the expression of c-kit increased in group MG(p<0.05). Compared with ME, the expression of CD29(p<0.01) and c-kit (p<0.05)increased in group MAE, CD29, CD90expressed more in group MAG, and CD29(p<0.01), CD90(p<0.01) and c-kit(p<0.05) expressed more in group MAGE than in group MGE.These show that, the number of stem cell in normal myocardium is very limited. After MI, less stem cells were homing to infarction area, aerobic exercise and/or mobilization intervention remarkably increased the number of BMSCs in the MI area,.AMD300blocked the combine of SDF-1and CXCR4, mobilized more BMSCs into periphery blood, and homing to the damaged myocardium by chemotactic factors. Conclusion:1This experiments have verified, MI badly damaged cardiac normal tissue structure, appeared alternative fibrosis phenomenon, formed cicatricial tissue, damaged the heart function; HIF-1, MCP-1, SDF-1, CD44, VLA-4, CD29, CD34, CD90, CXCR4and c-kit had little expression in the Infarction surrounding area.2This experiments have found that aerobics exercise and/or mobilization intervention after MI all can narrow the area of cicatricial tissue, increase effectively the rats cardiac function. SDF/CXCR4played an important role in the homing process of BMSCs which induced by aerobics exercise and/or mobilization intervention. Aerobics exercise and/or mobilization intervention also increased the expression of chemotactic factors, made more BMSCs homing to the injury area. And the effects was more significant by the intervention of aerobic exercise collaborative stem cell mobilization.3This experiments have found that AMD3100hadn’t made the expression of CD29, CD34, CD90,CXCR4and c-kit reduced in ischemic myocardium, there still a number of regeneration cardiomyocytes, and expression of chemotactic factors and adhesion molecule in the high level, which promoted the cardiac remolding and improved cardiac function. This paper speculated, in post-MI, except the SDF-1/CXCR4signal axis, bone marrow stem cells can also home to the damaged cardiac muscle through some of the non-CXCR4effect or through the activation of CSCs. For blocking agent effect was not obvious, the specific mechanism and dose need a further research.