心室内注射人脐带间充质干细胞改善心肌梗死大鼠心功能及作用机制

Human umbilical cord mesenchymal stem cells via intraventricular injection improve the cardiac function of myocardial infarction rats

背景:人脐带间充质干细胞具有分化潜力大,增殖能力强,免疫原性较低等特点,在创伤修复、局部缺血组织的血管再生等方面发挥不可估量的作用。目的:探讨心室内注射人脐带间充质干细胞对心肌梗死大鼠心肌组织粒细胞-巨噬细胞集落刺激因子、转化生长因子β1表达的影响。方法:选取成年雄性健康SD大鼠120只,随机选取20只为健康对照组,余100只于腹腔皮下多点注射异丙肾上腺素建立心肌梗死大鼠模型。造模成功后随机分为模型组、人脐带间充质干细胞上清液组、人脐带间充质干细胞低剂量组、中剂量组及高剂量组,每组20只。造模后24 h,分别将生理盐水注射液、人脐带间充质干细胞上清液、含0.25×10~6个,1.0×10~6个,4.0×10~6个人脐带间充质干细胞悬液2 mL缓慢注入心室。治疗2周后应用心脏超声测定左室射血分数、收缩末期左室容积及舒张末期左室容积。ELISA法测定血清乳酸脱氨酶、肌酸激酶及脑钠肽前体水平。取心脏标本,硝基四氮唑蓝染色法测定心肌梗死面积,Western blot法测定心肌组织粒细胞-巨噬细胞集落刺激因子、转化生长因子β1表达。结果与结论:(1)人脐带间充质干细胞低、中、高剂量组左室射血分数高于模型组及人脐带间充质干细胞上清液组,而收缩末期左室容积、舒张末期左室容积低于模型组及人脐带间充质干细胞上清液组(P<0.05),人脐带间充质干细胞中、高剂量组上述指标优于低剂量组(P<0.05);(2)人脐带间充质干细胞低、中、高剂量组血清乳酸脱氨酶、肌酸激酶及脑钠肽前体水平及心肌组织粒细胞-巨噬细胞集落刺激因子、转化生长因子β1表达均低于模型组及人脐带间充质干细胞上清液组(P<0.05),而人脐带间充质干细胞中、高剂量组上述指标低于低剂量组(P<0.05);(3)人脐带间充质干细胞低、中、高剂量组心肌梗死面积小于模型组及人脐带间充质干细胞上清液组(P<0.05),而人脐带间充质干细胞中、高剂量组心肌梗死面积小于低剂量组(P<0.05);(4)结果表明,人脐带间充质干细胞能明显降低心肌梗死大鼠心肌组织粒细胞-巨噬细胞集落刺激因子、转化生长因子β1表达,进而有效保护心肌组织,改善心功能。

BACKGROUND:Human umbilical cord mesenchymal stem cells(UC-MSCs),characterized by great differentiation potential,strong proliferation ability and low immunogenicity,exert an immeasurable role in wound repair and vascular regeneration in ischemic tissues.OBJECTIVE:To investigate the effect of intraventricularly injected UC-MSCs on expression of granulocyte-colonystimulating factor(GM-CSF)and transforming growth factor-β1(TGF-β1)in the myocardium of myocardial infarction rats.METHODS:120adult male Sprague-Dawley rats were selected randomly,among which,20healthy rats were randomly selected as controls and the rest rats were subcutaneously injected with isoproterenol to establish the myocardial infarction model.Model rats were randomized into model group,UC-MSC supernatant group,UC-MSC low-dose group,middle-dose group and high-dose group,with20rats in each group.Twenty-four hours after modeling,normal saline,UC-MSC supernatant,UC-MSC suspensions containing0.25×106,1.0×106,4.0×106cells(2mL)were injected intraventricularly into the rats in the corresponding groups,respectively.Left ventricular ejection fraction(LVEF),end-systolic left ventricular volume(LVESV)and left ventricular end-diastolic volume(LVEDV)were measured by echocardiography at2weeks after treatment.Serum lactate dehydrogenase(LDH),creatine kinase(CK)and pro-brain natriuretic peptide(Pro-BNP)were measured by enzyme-linked immunosorbent assay(ELISA).At the end of the experiment,10rats were killed by dislocation and the cardiac specimens were taken.The myocardial infarct size was determined by nitroblue tetrazolium staining.The expressions of GM-CSF and TGF-βin the myocardium of rats in each group were determined by western blot method.