Dihydromyricetin inhibits the M1 polarization of macrophage induced by oxidized low-density lipoprotein through JAK3/STAT5 signaling pathway

Abstract

Objective To observe the effect of dihydromyricetin(DMY) on the M1 polarization of macrophages induced by oxidized low-density lipoprotein(Ox-LDL) and to explore its mechanism. Methods RAW 264.7 cells were incubated in RPMI1640 medium containing Ox-LDL(50 mg/L) and DMY(40 μmol/L) for 24 h. The effect of JAK/STAT signaling pathway inhibitor AG-490 on DMY was observed.The levels of tumor necrosis factor-α(TNF-α), interferon-γ(IFN-γ), transforming growth factor-β(TGF-β) and interleukin-10(IL-10) in the supernatant of cell culture medium were detected by enzyme-linked immunosorbent assay(ELISA). The protein expressions of inducible nitric oxide synthase(iNOS) and arginase 1(Arg1) were tested by Western blot. Results Compared with the control group, the Ox-LDL group showed that the protein expression in macrophage of iNOS and levels of TNF-α and IFN-γ in the supernatant of culture medium were significantly increased(t=4.12, 2.89 and 3.44, P=0.023, 0.036 and 0.031), while the protein expression of Arg1 in cells and levels of TGF-β and IL-10 in the supernatant of culture medium were significantly decreased(t=3.71, 2.31 and 2.67, P=0.034, 0.038 and 0.034), and the ratios of p-JAK3/JAK3 and p-STAT5/STAT5 in cells were significantly increased(t=3.93 and 2.65 and P=0.007 and 0.021). Compared with the Ox-LDL group, the Ox-LDL+ DMY group showed that the protein expression of iNOS in cells and levels of TNF-α and IFN-γ in the supernatant of culture medium were significantly decreased(t=5.74, 2.37 and 3.07, P=0.022, 0.031 and 0.033), while the protein expression of Arg1 in cells and levels of TGF-β and IL-10 in the supernatant of culture medium were significantly increased(t=3.94, 2.19 and 2.44, P=0.025, 0.047 and 0.035), and the ratios of p-JAK3/JAK3 and p-STAT5/STAT5 in cells were significantly decreased(t=3.41 and 2.32, P=0.015 and 0.023). Compared with the Ox-LDL+ DMY group, the Ox-LDL+ DMY+ AG-490 group showed that the protein expression of iNOS and levels of TNF-α and IFN-γ in supernatant of culture medium were significantly increased(t=3.14, 3.41 and 3.74, P=0.017, 0.028 and 0.023), while the protein expression of Arg1 and levels of TGF-β and IL-10 were significantly decreased(t=2.87, 2.85 and 3.47, P=0.025, 0.035 and 0.028). Conclusions Dihydromyricetin inhibits the M1 polarization of macrophages induced by Ox-LDL, and the mechanism may be related with the activation of JAK3/STAT5 signaling pathway. Key words: Atherosclerosis; Lipoprteins, LDL; Macrophage activation