Abstract: Objective To investigate the effect of high salt concentration on the phenotypes, lymphatic endothelial cell characteristics and functions of endothelial growth factor receptor (VEGFR)-3+ macrophages. Methods The VEGFR-3+subsets in mouse RAW264.7 macrophages were sorted by flow cytometry and divided into control group, low salt group (LS group, 20 mmol/L NaCl) and high salt group (HS group, 40 mmol/L NaCl). The viability of VEGFR-3+ cells was measured by CCK-8 method in different groups. Real-time PCR was used to detect the changes of VEGFR-3+ macrophage phenotypes and the mRNA expression levels of lymphatic endothelial cell markers after the intervention. Transwell assay was used to detect the migration of three groups. The phagocytosis ability was measured by flow cytometry. Results The levels of IL-1β, TNF-α, CCL2, VEGF-C and TonEBP mRNA were significantly increased in HS group compared with those of control group (P＜0.05). After 24 h and 48 h high salt intervention, the viability of VEGFR-3+ macrophages was significantly decreased in HS group compared with those of LS group (P＜0.05). Meanwhile, the migration and the phagocytosis ability were also significantly increased in HS group compared with those of control group (P＜0.05). Conclusion The VEGFR-3+ macrophages can migrate to M1-type macrophages and show lymphangiogenesis-promoting characteristics after high salt intervention, which provides a theoretical basis for our further study about the relationships between this subpopulation and lymphangiogenesis and cardiovascular diseases.

Key words: macrophages, immunophenotyping, lymphangiogenesis, vascular endothelial growth factor receptor-3, high salt