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目的探讨脐血间充质干细胞(UCMSCs)移植对盐敏感性高血压大鼠心肌纤维化和心肌细胞凋亡的影响。方法 60只Dahl大鼠,采用皮下注射辣椒辣素构建盐敏感性高血压实验动物模型,按随机数字表法随机分为正盐组、高盐组及UCMSCs移植组,每组20只。正盐组给予0.3%氯化钠饮食,高盐组给予8%氯化钠饮食,UCMSCs移植组予8%氯化钠饮食。8周之后,UCMSCs移植组大鼠尾静脉注射UCMSCs 1 ml(3×106个/ml PKH-26标记的UCMSCs),连续治疗3 d。实验2周末对大鼠进行超声心动图检测左室射血分数(LVEF)及左室短轴缩短率(FS),计算左心指数。HE染色观察心肌细胞形态,进行Van Gieson(VG)染色应用计算机图像分析系统测算胶原容积积分(CVF);荧光显微镜观察PKH-26标记的UCMSCs在心肌组织中分布情况,TUNEL法检测各组大鼠心肌细胞凋亡情况。结果 (1)正盐组大鼠的心肌细胞排列有序,心肌间质无炎症细胞浸润及纤维化瘢痕形成;高盐组心肌细胞排列紊乱,巨噬细胞浸润明显增多同时伴有明显的纤维化重构;与高盐组相比较,UCMSCs移植组尽管有炎性细胞浸润但心肌细胞排列有序,且无纤维化瘢痕组织形成,心肌的纤维化重构较轻。(2)与正盐组相比,高盐组大鼠的LVEF和FS显著降低(P均<0.05),其左心指数明显上升(P<0.05)。与高盐组相比,UCMSCs移植干预之后大鼠的LVEF和FS明显的提高(P均<0.05),而左心指数降低(P<0.05)。(3)心脏CVF正盐组最低,UCMSCs移植组次之,而高盐组最高,各组组间差异有统计学意义(P<0.05)。(4)仅在UCMSCs移植组的实验大鼠心肌组织中可见较多的PKH-26标记的UCMSCs。(5)正盐组、高盐组、UCMSCs移植组心肌细胞凋亡率分别为0、(28.2±6.3)%、(12.7±2.6)%,与高盐组比较,UCMSCs移植组大鼠心肌细胞凋亡率明显降低(P<0.05)。结论UCMSCs移植能减轻盐敏感性高血压大鼠心脏纤维化,减少胶原沉积,减少心肌细胞凋亡,改善大鼠心脏功能。
Objective To investigate the effects of cord blood derived mesenchymal stem cells (UCMSCs) transplantation on myocardial fibrosis and cardiomyocyte apoptosis in salt-sensitive hypertensive rats. Methods Sixty Dahl rats were injected subcutaneously with capsaicin to establish a model of salt-sensitive hypertension. The rats were randomly divided into normal salt group, high salt group and UCMSCs transplantation group, with 20 rats in each group. The normal saline group was given 0.3% sodium chloride diet, the high salt group was given 8% sodium chloride diet, and the UCMSCs transplantation group was given 8% sodium chloride diet. After 8 weeks, 1 ml UCMSCs (3 × 106 / ml PKH-26 labeled UCMSCs) were injected into the tail vein of UCMSCs transplantation group for 3 days. At the end of experiment 2, left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (FS) were measured by echocardiography and left index was calculated. The morphology of cardiomyocytes was observed by HE staining and the collagen volume integral (CVF) was measured by computer image analysis system under Van Gieson (VG) staining. The distribution of PKH-26 labeled UCMSCs in myocardium was observed by fluorescence microscopy. Cardiomyocyte apoptosis. Results (1) The cardiomyocytes of rats in normal salt group were arranged in an orderly manner, infiltration of inflammatory cells and formation of fibrosis scar in the myocardial interstitium. The myocardial cells in the high salt group were disordered, the infiltration of macrophages was significantly increased, accompanied by obvious fibrosis Compared with the high-salt group, UCMSCs transplanted in the UCMSCs transplantation group had inflammatory cell infiltration but myocardial cells were arranged in an orderly manner, and no fibrotic scar tissue was formed. The remodeling of myocardial fibrosis was lighter. (2) Compared with normal saline group, LVEF and FS in high salt group decreased significantly (all P <0.05), and left index increased obviously (P <0.05). Compared with the high salt group, the LVEF and FS in rats after UCMSCs transplantation were significantly increased (all P <0.05), while the left heart index decreased (P <0.05). (3) The heart CVF positive salt group was the lowest, followed by the UCMSCs transplantation group, while the highest salt group was the highest with significant difference (P <0.05). (4) PKH-26-labeled UCMSCs were found only in the myocardial tissue of experimental rats transplanted with UCMSCs. (5) The apoptotic rates of cardiomyocytes in normal saline group, high salt group and UCMSCs transplantation group were 0, (28.2 ± 6.3)% and (12.7 ± 2.6)%, respectively. Compared with high salt group, The apoptosis rate was significantly lower (P <0.05). Conclusion UCMSCs transplantation can relieve cardiac fibrosis, reduce collagen deposition, decrease cardiomyocyte apoptosis and improve cardiac function in salt-sensitive hypertensive rats.