高盐干预对盐敏感高血压大鼠心脏microRNA133a表达及纤维化的影响
Effects of dietary high-salt intake on fibrosis and expression of microRNA133a in Dahl S rats’ myocardium

摘要：目的 观察高盐摄入对Dahl盐敏感大鼠及SD大鼠的血压、左室质量、心肌microRNA133a以及纤维化水平的影响，探讨microRNA133a在高盐干预的盐敏感性高血压心肌纤维化中的作用。方法 以Dahl盐敏感大鼠及SD大鼠为动物模型，给予高盐饮食喂养4周，并设置低盐对照组。用tail-cuff法监测各组大鼠血压变化、并检测左室质量指数(LVWI)、左心室心肌组织胶原蛋白I(CollagenⅠ)、结缔组织生长因子(connective tissue growth factor, CTGF)及microRNA133a的表达量。结果 高盐组大鼠的血压均比干预前升高，与SD大鼠相比，Dahl盐敏感大鼠高盐组较低盐组血压升高幅度更为显著(P<0.01)。Dahl盐敏感大鼠高盐组LVWI、CollagenⅠ与CTGF表达量均较低盐组明显增加(P<0.01)，而SD大鼠两组间无明显差异(P>0.05)。各高盐组microRNA133a表达量均比低盐组下调(P <0.01)，Dahl盐敏感大鼠高盐组microRNA133a表达量较SD大鼠高盐组下降更为显著(P<0.05)。结论 高盐可能通过下调心肌microRNA133a的表达参与盐敏感性高血压心肌纤维化。
ABSTRACT: Objective To observe the influence of high-salt intake on the blood pressure, weight of left ventricle, myocardial microRNA133a and fibrosis levels by implementing the high-salt diet intervention trial in Dahl salt-sensitive rats and SD rats so as to explore the role of microRNA133a in salt-sensitive hypertensive cardiac fibrosis with high-salt intervention. Methods Sixteen 4-week male Dahl salt-sensitive rats are divided into two groups, 8 in the SLS group and 8 in the SHS group. Similarly, sixteen 4-week male SD rats were divided into two groups. Systolic blood pressure of the rats was measured by the indirect tail-cuff method. Left ventricular mass index was measured after the rats were sacrificed. The expression levels of left ventricular myocardial tissue collagen I (LVMI), connective tissue growth factor (CTGF) expression and microRNA133a were observed. Results Blood pressure in high-salt groups both increased (P<0.01). Compared with that of SD rats, blood pressure was more significantly increased in high-salt group than in low-salt group of Dahl salt-sensitive rats (P<0.01). After the intervention of high-salt diet, LVMI, CTGF and collagen I expression in Dahl salt-sensitive rats increased more significantly than the low-salt group, with a significant difference (P<0.01); however, there was no significant difference between high-salt and low-salt groups (P>0.05). After the intervention, microRNA133a expression was significantly decreased in all high-salt groups compared with that in low-salt groups (P<0.01), and the expression decreased more significantly in high-salt group of Dahl salt-sensitive rats than in high-salt group of SD rats (P<0.05). Conclusion High-salt diet is probably involved in salt-sensitive hypertension myocardial fibrosis by downregulating the expression of myocardial microRNA133a