Dynamic changes of circulating monocyte subsets in high-NaCl diet fed mice

Objective To observe the dynamic changes of the circulating monocyte subsets in C57BL/6 mice fed with high-NaCl diet. Methods Male C57BL/6 mice were randomly divided into three groups: 9, 40 and 80 g/L NaCl groups. Before the treatment and 4, 8 and 12 weeks after the treatment, the cardiac function was dynamically determined by echocardiography and the blood pressure was measured by tail-cuff plethysmography. Flow cytometry analysis of circulating monocyte subsets was performed. HE staining was used to observe cardiac pathological changes at the time of sacrifice. Results Systolic blood pressure significantly increased with the progression of the high-salt diet. Compared with 9 g/L NaCl group, the ejection fraction of the other two groups slightly increased at week 4, followed by a significant decreasing trend up to week 12, in addition, the percentage of Ly6C(high) monocyte subset showed a progressive increase during high-salt feeding and reached a plateau at week 4, and then abruptly went down up to week 12. On the contrary, Ly6C(low) monocyte subset had an opposite trend, whereas Ly6C(int) monocyte subset remained constant. HE staining showed that cardiomyocyte size, as determined by the myocyte cross-sectional area, became enlarged obviously in the latter two groups. Conclusion Circulating monocyte subsets dynamically changed in the mice fed with high-salt diet.