Effects of dietary high-salt intake on fibrosis and expression of microRNA133a in Dahl S rats' myocardium

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.