骨髓单个核细胞移植对梗死后心脏形态、结构及功能的影响

Effects of Bone Marrow Mononuclear Cells Implantation on Morphology,Structure,and Ventricular Function of Infarct Heart in Dogs

目的研究骨髓单个核细胞移植梗死心肌后心脏形态、结构和功能的变化。方法将24条成年杂种犬随机分为4组:急性心肌梗死对照组、急性心肌梗死移植组、陈旧心肌梗死对照组和陈旧心肌梗死移植组,每组6条。急性、陈旧心肌梗死移植组用心肌直接注射法行自体骨髓单个核细胞移植,急性、陈旧心肌梗死对照组注射等体积无细胞的磷酸盐缓冲液。移植前和移植后6周分别用超声心动图观察心脏形态和功能的变化,处死动物后行心脏大体形态、结构和组织病理学观察。结果超声心动图观察结果显示,移植后急性心肌梗死移植组左心室舒张期末内径(LVEDD)、左心室舒张期末容积(LVEDV)、左心室后壁厚度(LVPW)均较其相应的对照组减小(32.5±5.1mmvs.36.6±3.4mm,46.7±12.1mlvs.57.5±10.1ml,6.2±0.6mmvs.6.9±0.9mm;P<0.05);陈旧心肌梗死移植组LVEDD、LVEDV和LVPW均较其相应的对照组减小(32.8±4.2mmvs.36.8±4.4mm,48.2±12.9mlvs.60.6±16.5ml,7.0±0.4mmvs.7.3±0.5mm;P<0.05)。陈旧心肌梗死移植组在细胞移植后射血分数较其相应的对照组升高(53.3%±10.3%vs.44.7%±10.1%)。大体形态学观察细胞移植后急性、陈旧心肌梗死移植组梗死区厚度较相应的对照组增加(7.0±1.9mmvs.5.0±2.0mm,6.0±0.6mmvs.4.0±0.5mm;P<0.05),而梗死区长径较对照组减小(25.5±5.2mmvs.32.1±6.2mm,33.6±5.5mmvs.39.0±3.2mm,P<0.05);急性心肌梗死移植组无室壁瘤发生。而陈旧心肌梗死移植组长轴/短轴周长较对照组增加(0.581±0.013vs.0.566±0.015;P<0.05)。两移植组于细胞移植后在移植细胞区均观察到荧光表达,但多数核形态不规则,未观察到发荧光的成熟心肌细胞核。组织学观察见细胞移植后均有较多新生毛细血管生成,急性心肌梗死移植组有较多淋巴细胞浸润。结论骨髓单个核细胞移植在急性或陈旧心肌梗死期均发挥了有益的作用,在形态和结构上抑制了心室重构的发展,同时促进了血管新生,从而改善了心功能。

Objective To observe the changes in morphology, structure, and ventricular function of infarct heart after bone marrow mononuclear cells （BMMNC） implantation. Methods Twenty-four dogs were divided into four groups with random number table, acute myocardial infarction （AMI） control group, AMI-BMMNC group, old myocardial infarction （OMI） control group and OMI-BMMNC group, 6 dogs each group. Autologous BMMNC were injected into infarct and peri-infarct myocardium for transplantation in AMI-BMMNC group and OMI-BMMNC group. The same volume of no-cells phosphate buffered solution （PBS） was injected into the myocardium in AMI- control group and OMI-control group. Before and at six weeks of cell transplantation, ultrasonic cardiography （UCG） were performed to observe the change of heart morphology and function, then the heart was harvested for morphological and histological study. Results UCG showed that left ventricular end diastolic dimension （LVEDD）, left ventricular end diastolic volume（LVEDV）, the thickness of left ventricular postwall（LVPW）in AMI-BMMNC group were significantly less than those in AMI-control group（32.5±5.1 mm vs. 36.6±3.4mm, 46.7±12.1 ml vs. 57.5±10. 1ml, 6.2±0.6mm vs. 6.9±0.9mm; P〈0.05）. LVEDD, LVEDV, LVPW in OMI-BMMNC group were significantly less than those in OMI-control group （32. 8±4. 2 mm vs. 36.8 ±4.4mm, 48. 2 ±12. 9ml vs. 60. 6± 16. 5ml, 7.0±0.4mm vs. 7.3±0.5mm; P〈0.05）. The value of eject fraction （EF） in OMI-BMMNC group were significantly higher than that in OMI-control group（53. 3%±10. 3% vs. 44. 7%±10. 1%）. Compared with their control group in morphological measurement, the increase of infarct region thickness （7. 0 ±1. 9mm vs. 5. 0 ± 2.0mm, 6.0± 0.6mm vs. 4.0 ± 0. 5mm ; P 〈 0.05） and the reduction of infarct region length （25. 5 ± 5. 2mm vs. 32.1±6.2mm,33.6±5.5mm vs. 39.0±3.2mm, P〈0.05） were observed after transplantation in AMI-BMMNC group and OMI-BMMNC group, no ventricular aneurysm was found in AMI-BMMNC group, and the ratio between long axis and minor axis circumference of left ventricle increased in OMI-BMMNC group（0. 581±0. 013 vs. 0. 566± 0. 015;P〈0. 05）. Both in AMI-BMMNC group and OMI-BMMNC group, fluorescence expressed in transplantation region was observed, the morphology of most nuclei with fluorescence was irregular, and the differentiated cardiocyte with fluorescence was not found in myocardium after transplantation. The histological examination showed more neovascularization after transplantation both in AMI and in OMI, and significant lymphocyte infiltration in AMI- BMMNC group. Conclusion BMMNC implantation into infarct myocardium both in AMI and OMI have a beneficial effect, which can attenuate deleterious ventricular remodeling in morphology and structure, and improve neovascularization in histology, and improve the heart function.