Résumé
BACKGROUND:Now, the bone marrow mesenchymal stem cel homing is thought to be mediated by adhesion molecules and chemokines, and this process involves bone marrow endothelial cel s, hematopoietic stem cel s, bone marrow microenvironment and its secreted or expressed molecules, in which, adhesion molecules may play an important role. OBJECTIVE:To explore the migrating and chemotactic mechanism of bone marrow mesenchymal stem cel s via acupoint injection into myocardial cel s by determining the expression of vascular cel adhesion molecule-1 and very late antigen-4. METHODS:Bone marrow mesenchymal stem cel s were cultured using adherent method, and the passage 3 cel s were used as seed cel s at a density of 1×1010/L. Sixty Sprague-Dawley rats were randomly divided into sham group, model group, myocardial injection group, and acupoint injection group, 15 rats in each group. The left coronary arteries of rats were ligated for establishing a model of myocardial infarction. At 72 hours after myocardial infarction, 0.3 mL bone mesenchymal stem cel s were transplanted into the Xinyu, Zhiyang, Tanzhong acupoints, respectively, in the acupoint injection group;while in the myocardial injection group, secondary thoracotomy was done, and 1.2 mL bone marrow mesenchymal stem cel s were equably transplanted into six sites in the feeding area of the left anterior descending artery and the surrounding myocardium. At 4 weeks after myocardial infarction, a multi-channel polygraph was adopted for detection of hemodynamic parameters, and the levels of serum vascular cel adhesion molecule-1 and very late antigen-4 were measured by ELISA. RESULTS AND CONCLUSION:The heart function of rats in the myocardial injection and acupoint injection groups were improved, and compared with the model group, the levels of serum vascular cel adhesion molecule-1 and very late antigen-4 were significantly higher in the myocardial injection and acupoint injection groups. However, there was no significant difference between the myocardial injection and acupoint injection groups. These findings suggest that vascular cel adhesion molecule-1 and very late antigen-4 may be one of the chemotactic mechanisms of bone mesenchymal stem cel s transplanted in myocardial infarction model rats by acupoint injection.
Résumé
Objective To explore the effect of acupoint injection of bone marrow mesenchymal stem cells (BMSCs)on hemodynamics of rat model with acute myocardial infarction(AMI). Methods Sixty Sprague-Dawley (SD)rats were randomly divided into sham group,model group,myocardium injection BMSCs group and acupoint injection BMSCs group(each n=15). The left anterior descending coronary artery(LAD)was ligated to establish a rat model of AMI. After the rat model was successfully established for 72 hours,0.2 ml BMSCs(1×1010/L)were transplanted by a micro-quantity syringe at 6 points in equal amount in the LAD blood-supply area and its periphery in the myocardial injection group,while in the acupoint injection group,0.3 ml BMSCs(1×1010/L)was transplanted at each of the following acupoints:Xinshu,Zhiyang and Tanzhong. Four weeks after AMI,polyethylene tubing was inserted into the right carotid artery to measure the hemodynamics,at the same time animals were sacrificed,and the heart was take out to calculate the heart mass index(HMI)and left ventricular mass index(LVMI). Results One, 3,5 and 4 rats were respectively dead in the sham group,model group,myocardium injection group,and acupoint injection group during the experimental period. Compared with the sham group,the left ventricular systolic pressure (LVSP,mm Hg,1 mm Hg=0.133 kPa),the maximum rate of increase of left ventricular pressure(+dp/dt max, mm Hg/s), the maximum rate of decrease of left ventricular pressure(-dp/dt max,mm Hg/s), the maximum logarithmic change rate of left ventricular pressure〔(dp/dt)?P-1max,s-1〕,HMI(mg/g),LVMI were significantly decreased,and left ventricular end-diastolic pressure(LVEDP,mm Hg),heart rate(HR,bpm)were obviously increased in model group(all P<0.05). Compared with the model group,the LVSP,+dp/dt max,-dp/dt max, (dp/dt)?P-1max, HMI,LVMI were significantly increased in myocardial injection group and acupoint injection group〔LVSP:130.38±14.96,124.36±14.36 vs. 114.36±12.71,+dp/dt max:4707.52±394.36,4597.14±411.05 vs. 3791.43±327.29,-dp/dt max:4075.11±317.89,3938.05±373.76 vs. 3116.32±275.04,(dp/dt)?P-1max:215.26±21.29,197.39±18.96 vs. 155.93±25.14〕,and the LVEDP and HR were significantly decreased(LVEDP:5.15±2.39,5.64±1.96 vs. 10.58±2.49,HR:400.50±42.58,395.55±44.62 vs. 414.51±35.75,all P<0.05). There were no significant differences in above indexes between myocardium injection group and acupoint injection group. Conclusion Acupoint injection of BMSCs can improve the heart function of rat model with AMI.
Résumé
BACKGROUND: Stem cell transplantation can significantly improve heart function foUowing myocardial infarction. This is correlated with the differentiation of stem cells into cardiomyocytes and promotion effect on angiogenesis. Paracrine and ventricular reconstruction inhibition (especially extracallular collagen reconstruction) have important effects on improving heart function.OBJECTIVE: To investigate the effects of bone marrow mesenchymal stem cell (BMSC) transplantation on coUagen remodeling after acute myocardial infarction in rabbits.DESIGN, TIME AND SETTING: The randomized controlled animal study was performed at the Laboratory of Acupuncture and Electrophysiology of Liaoning University of Traditional Chinese Medicine from June to August 2007.MATERIALS: A total of 57 healthy Japanese rabbits were purchased from Experimental Animal Center, Uaoning University of Traditional Chinese Medicine.METHODS: BMSCs were acquired from the bone marrow of two rabbits, and marked with BrdU before transplantation. Ten rabbits served as a normal group. Forty-five rabbits were used to establish the left ventricular infarct by ligation of the left coronary artery. Thirty success models of myocardial infarction were randomly divided into 3 groups (n=10)" model, saline and call transplantation groups. Following 7 days of myocardial infarction, rabbit models in the cell transplantation group were injected in the ear vein with 1 mL of BMSCs (2x106 cells). Rabbits in the saline group were infused with 1 mL of saline. The culture was performed for 5 weeks.MAIN OUTCOME MEASURES: Fibrous structure of myocardial stroma was observed, and collagen volume fraction was measured by Masson Trichrome staining. The ratio of type Ⅰ and Ⅲ collagen was determined by immunohistochemistry.RESULTS: BrdU-positive BMSCs could be seen in the cell transplantation group. After myocardial infarction, a few collagen fibers was confluent in or surrounding the infarct area, arranged orderly in the cell transplantation group. Collagen fiber plaque-shaped confluence was significant, and arranged disorderly in the model and saline groups. At 5 weeks following myocardial infarction, compared with the normal group, collagen volume fraction was significantly decreased in and surrounding the infarct region (P < 0.05), and the ratio of type Ⅰ and Ⅲ collagen was increased significantly in the model group (P < 0.05).Compared with the model group, collagen volume fraction and the ratio of type Ⅰ and Ⅲ collagen were significantly decreased (P< 0.05).CONCLUSION: BMSCs could survive in infarct heart. BMSCs transplantation could reduce collage volume and improve collage ratio and had beneficial effects on collage remodeling processes after acute myocardial infarction.