摘要
目的:骨髓基质干细胞移植到心肌梗死的瘢痕心肌组织中可以改善心功能,但以心电图为观察指标的研究不多。实验观察骨髓基质干细胞移植对正常和心肌梗死大鼠心电图及心功能的影响。方法:实验于2004-01/2005-03在哈尔滨医科大学完成。①实验动物:选取4周龄雄性Wistar大鼠80只,随机数字表法分为梗死移植组、正常移植组、梗死非移植组、正常非移植组,20只/组。另选取7d龄Wistar雄鼠30只作为骨髓基质干细胞的来源。②实验方法:采用密度梯度离心法获取鼠骨髓基质干细胞,配成1×109L-1的细胞悬液,使用5-氮胞苷体外诱导培养3～4周,移植前24～48h行Brdu标记。取载有细胞的盖玻片,测定钙释放时将20mmol/L的caffeine快速加在细胞表面。梗死移植组、梗死非移植组大鼠建立心肌梗死模型。造模4周后,梗死移植组将0.25mL诱导的骨髓基质干细胞悬液注射至大鼠心肌梗死后的瘢痕组织,正常移植组同法将骨髓基质干细胞悬液注射至正常心肌组织,梗死非移植组、正常非移植组注射等量不含骨髓基质干细胞的培养液基质。③实验评估:观察骨髓基质干细胞的诱导分化情况及其植入后在瘢痕心肌组织中的生存状态。测定细胞内钙离子浓度。记录术前、冠脉结扎后即刻/细胞移植即刻、术后4周的心电图变化。检测术后4周的超声和血流动力学指标变化。结果:80只大鼠均进入结果分析。①骨髓基质干细胞的诱导分化及其植入后的生存状态:5-氮胞苷诱导3周后,骨髓基质干细胞表达肌钙蛋白Ⅰ和肌凝蛋白重链,细胞内有丰富的肌丝和Z线,细胞器较多。植入4周后在心肌瘢痕组织中分化为心肌细胞。②细胞内钙离子浓度:两组细胞在caffeine刺激下钙离子的释放均呈波峰状,但诱导组应用caffeine后钙离子浓度降低且低于基础状态,钙释放受到抑制,未诱导组不受影响。③心电图观察:与术前比较,梗死移植组QRS波变窄,R波降支出现正常顿挫波,未见显著心律失常。④超声检测及血流动力学分析:术后4周,与梗死非移植组比较,梗死移植组左室收缩末压、左室射血分数和压力变化速率最大值均显著升高(P<0.05或0.01)。结论:骨髓基质干细胞体外诱导后能分化为心肌样细胞,植入到瘢痕心肌组织中生存、增殖良好,可改善心电图及心肌弹性,从而改善心肌梗死大鼠的心功能。
AIM： Mesenchymal stem cells （MSCs） can improve cardiac function in myocardial infarcted tissues, but the articles using electrocardiogram （ECG） as observational index are less. This experiment was designed to study the influence of MSC transplantation on the ECG and cardiac function of the normal and post-myocardial infarction （MI） rats. METHODS： The experiment was performed at Harbin Medical University from January 2004 to March 2005.①Eighty male Wister rats aged 4 weeks were randomly divided into 4 groups, MSC transplantation group, normal transplantation control group, non-transplantation MI control group and non-transplantation normal control group with 20 rats in each group. Another 30 male Wister rats aged 7 days were selected as the source of MSCs. ②MSCs were collected from the bone marrow of rats by density gradient centrifugation, and then made into 1×10^9 L^-1 cell suspension, induced with 5-azacytidine （5-aza） and cultured for 3-4 weeks, then labeled with Brdu 24-48 hours before transplantation. Coverslips with cells were added with 20 mmol/L caffeine. Rats in MSC transplantation group and non-transplantation MI control group were made into models of myocardial infarction. Four weeks later, 0.25 mL induced MSCs were transplanted into the scar region of the heart of the MI model rats in the MSC transplantation group. MSCs were transplanted into the heart of normal rats of the normal transplantation control group. The culture medium of the same volume was respectively injected into the heart of rats in the non-transplanfation MI control group and non-transplantation normal control group. ③The differentiation and living state of MSCs in the scar tissues after transplantation was observed. Intracellular calcium concentration was determined and ECG alteration of the rats was observed before transplantation, immediately after artery ligation/immediately after cell transplantation and 4 weeks after operation. Ultrasound and Hemodynamic indexes were measured 4 weeks after transplantation. RESULTS： Totally 80 rats were involved in the result analysis. ①Differentiation and living state after transplantation of MSCs： MSCs induced by 5-aza for 3 weeks expressed myosin Ⅰ and troponin. Induced MSCs were indicated by the presence of myofilaments and Z line in the cytoplasm and with more cellular organ. The induced MSCs differentiated into cardiomyocyte-like cells in the scar tissues after transplantation for 4 weeks. ②Density of intracellular calcium： Releasing of calcium in both groups expressed ridge shape under the stimulation of caffeine. But the density of calcium in the induced group depressed and lower than foundational condition, and releasing of calcium was inhibited. While the non-induced group was not influenced.③Electrocardiograph： Compared with that before MSC transplantation, QRS of the MI rats receiving MSC transplantation became narrowed and a setback on the descending branch of R wave, which was similar to the setback on the normal R wave, was observed. No significant arrhythmia was found in the MI rats receiving MSC transplantation. ④Ultrasound and hemodynamics： Left ventricular systolic pressure （LVSP）, maximal rate of ventricular pressure （dp/dtmax） and left ventricular ejection fraction （LVEF） in the MSCs transplantation group were higher than those in the non-transplantation MI control group 4 weeks after transplantation （P〈0.05 or 0.01）. CONCLUSION： MSCs can differentiate into cardiomyocyte-like cells, and live and proliferate in the scar region of the heart of MI rats, and improve ECG and myocardial elasticity to ameliorate cardiac function of the rats.
出处
《中国组织工程研究与临床康复》
CAS
CSCD
北大核心
2007年第28期5553-5556,共4页
Journal of Clinical Rehabilitative Tissue Engineering Research
基金
国家自然科学基金资助(30170369)
黑龙江省自然科学基金资助(9826)~~
