(76) found in an in vitro LECs model that M2b macrophage cultures could upregulate vascular endothelial growth factor receptor-3 (VEGFR-3) and VEGF-C expression in LECs, stimulate cell migration and cell proliferation of LECs, and increase the total length of the lymphatic vessels, the length of the total branching, the number of the nodes and the number of the nodal points; In an in vivo MI/RI rat model, cardiac M2b macrophage transplantation upregulated VEGFR-3 and VEGF-C expression, promoted lymphatic vessel neogenesis, inhibited myocardial fibrosis, and improved cardiac function. Here, FLT4 is linked to Myocardial fibrosis.