Effects Of Guanxin â…¡ Combined With Bone Marrow Mesenchymal Stem Cell Transplantation On Acute Myocardial Infarction In Rats

Backgrounds: The main mechanisms of pathologic physiology after acute myocardial infarction (AMI) are myocardial ischemia, necrosis. Then the necrotic cells are replaced by the fibroblast cells and loss the function of contraction, and finally, these leads to irreversible ventricular remodeling. Transplantation of bone marrow mesenchymal stem cells (BMSCs) had been proved be an effective method in treating myocardial infarction in both animal experiments and phaseⅠclinical trials. However, ischemia/hypoxia and early inflammatory reaction following myocardial infarction are not beneficial for transplanted cells to survival, and therapeutic efficacy is limited. GuanXinⅡis a traditional medicine, it's therapeutical principle is activating blood circulation to dissipate blood stasis. GuanXinⅡhas an exact effect in treating coronary heart disease(CHD)in both animal experiments and clinical trials. This study is to investigate synergetically therapeutical effects of GuanXinII and BMSCs transplantation on AMI.Objective: To observe the effects of GuanXinII combined with BMSCs transplantation on cardiac function, myocardial fibrosis and ventricle remodeling of acute myocardial infarction(AMI) rat models, and investigate the synergetically therapeutical effects of GuanXinII and BMSCs transplantation on AMI, and provid the evidences for clinical application.Methods: BMSCs were cultured using the whole bone marrow and differential adherence method. At the third passage, BMSCs were labeled with CM-DiI cell-labeling solution. 74 male SD rats were randomly divided into Control group(n=10), Model group(n=16), GuanXinⅡgroup(n=16), BMSCs group(n=16), GuanXinII+BMSCs group (n=16). In the last four groups, the left coronary artery ligation were used to build the models of acute myocardial infarction. After models were successfully built, L-DMEM was injected into 5 points in the infarcted myocardial sites and their marginal zones in model group and GuanXinⅡgroup; 2×106 BMSCs labled CM-DiI were injected into 5 points in the infarcted myocardial sites and their marginal zones in BMSCs group and GuanXinII+BMSCs group . Saline was daily fed for 1 week by intragastric administration in model group and BMSCs group. GuanXinII decoction (equivalent to rude drug 10g/kg) was daily fed for 1 week by intragastric administration in GuanXinⅡgroup and GuanXinII+BMSCs group. After 4 weeks, these data were detected and collected: Doppler echocardiography was used to detect cardiac function: LVIDd, LVIDs, FS, EF; Enzyme-linked inmunosorbent assay was used to detect the concentration of PⅠCP and PⅢNP in blood serum; The transplanted labeled BMSCs were detected in the cardiac muscle tissue sections by fluorescence microscope; Myocardic fibrosis was investigated by Masson's trichrome staining; Expression of TGF-β1 mRNA in the marginal zones of infarcting myocardial sites was measured by fluorescent quantitation reverse transcription-polymerase chain reaction (RT-PCR).Results: (1) BMSCs in vitro grew in adherence, were mostly fusiform and cuboidal, fibroblast-like cells. Their initial growth was characterized by the formation of colonies . They didn't differentiate even after passage 5-6. (2) dead cases in each group: 4 in model group, 3 in GuanXinII group, 4 in BMSCs group, 3 in GuanXinII+BMSCs group. There were not significant different among the 4 groups(P>0.05) . (3) Results of cardiac function: Compared with the control group, LVIDd and LVIDs were significantly increased and FS and EF were significantly decreased in model group, BMSCs group, GuanXinII group and GuanXinII+MSCs group(P<0.01). Compared with the model group, LVIDd and LVIDs were significantly decreased and FS, EF were significantly increased in the GuanXinII group, BMSCs group and GuanXinII+BMSCs group (P<0.01 or 0.05). The changes were better in the GuanXinII+BMSCs group compared with the GuanXinII group and BMSCs group (P<0.01 or 0.05). (4) Under the fluorescence microscope, transplanted BMSCs, erupting red fluorescence, distributed diffusedly in the frozen section of AMI marginal zone of the left ventricle in the BMSCs group and GuanXinII+BMSCs group. (5) Masson trichrome staining showed that AMI sites were taken the place of collagen fiber; ventricular wall thinned; collagen content and fibrotic extent increased. The changes were better in the GuanXinII+BMSCs group compared with the GuanXinII group and BMSCs group. There was no fiber formation and the cardiac muscles lined up in order in the control group. (6) The expression of TGFβ1m RNA of 4 AMI model groups were significantly higher than the control group (P<0.01); Compared with the model group, expression of TGF-β1mRNA were significantly decreased in the GuanXinII group, BMSCs group and GuanXinII+BMSCs group(P<0.01). The changes were better in the GuanXinII+BMSCs group compared with the GuanXinII group and BMSCs group(P<0.05). (7) After AMI, type I and type III collagen synthesis increased at different extents. Compared with the model group, the serum level of PICP and PIIINP were significantly decreased in the GuanXinII group, BMSCs group and GuanXinII+BMSCs group (P<0.01). The changes were better in the GuanXinII+BMSCs group compared with the GuanXinII group and BMSCs group (P<0.01).Conclusions: (1) GuanXinⅡ, BMSCs transplantation and their combination could improve the cardiac function of AMI rats, decreased the degree of ventricular expansion. Their combination had an optimal effect, with synergetically therapeutic effects on myocardial infarction. (2) GuanXinⅡ, BMSCs transplantation and their combination could decrease collagen foemation, and lessen myocardial fibrosis of AMI rats, their combination had an optimal effect, which may be correlated with the down-regulation of TGF-β1 mRNA.