Abstract: Objective To investigate the effect of liraglutide, an analogue of glucagon-like peptide-1, on the proliferation and
migration of cardiac microvascular endothelial cells (CMECs) and explore the mechanism. Methods In vitro cultured CMECs
of SD rats were purified by differential adhesion method and identified immunocytochemically using CD31 antibody and
factor VIII. MTT assay was performed to assess the proliferation of the first-generation cells exposed to different
concentrations (0-1000 nm/L) of liraglutide. Western blotting was used to detect the activation of PI3K/Akt and MAPK/ERK
signaling pathways. BrdU fluorescent labeling and scratch assay were performed to observe the proliferation and migration of
CMECs following liraglutide treatment, and PI3K/Akt and MAPK/ERK pathway inhibitors LY294002 and PD98059,
respectively, were used to further confirm the role of these signaling pathways in regulating the proliferation and migration of
CMECs. Results Immunocytochemical staining demonstrated a proportion of double positive cells exceeding 95%. The cells
exhibited a logarithmic growth 48 h after plating. Liraglutide exposure concentration-dependently promoted the proliferation
of CMECs with the optimal concentration of 100 nmol/L (P<0.05). Liraglutide exposure of the cells for 24 h significantly
increased the levels of intracellular phosphorylated Akt and ERK (P<0.05), but pretreatment of the cells with Akt and ERK
signaling pathway inhibitors 1 h before liraglutide obviously reversed such effect (P<0.05). BrdU and scratch assay showed
that 100 nmol/L liraglutide significantly promoted the proliferation and migration of CMECs (P<0.05), but such effects were
obviously suppressed by Akt and ERK inhibitors (P<0.05). Conclusion Liraglutide promotes the proliferation and migration of
CMECs in vitro via PI3K/Akt and MAPK/ERK signaling pathways.