Inhibitory effects of Ellipticine on inflammation in lipopolysaccharide-induced RAW264.7 cells / 中华危重病急救医学

ABSTRACT

Objective To determine the inhibitory effects of Ellipticine (ELL) on inflammation in lipopolysaccharide (LPS)-induced RAW264.7 cells of mouse and explore its molecular mechanism.Methods The RAW264.7 cells in log phase were challenged by LPS (10 mg/L) to induce inflammation and then treated with ELL (0.05, 0.5, 5μmol/L). At the same time the cells treated with ELL (5μmol/L) were considered as ELL control group while without any stimulation as control group. After 12 hours intervention, the content of inflammatory factors in cell supernatant was detected by enzyme linked immunosorbent assay (ELISA), and then confirmed the most suitable concentration for the next experiment. After LPS of 10 mg/L was used to challenged RAW264.7 cells to cause inflammation, 5μmol/L ELL was used for intervention, and the mRNA expressions of inflammatory cytokines were detected by reverse transcription-polymerase chain reaction (RT-PCR) after 2, 4, 6 and 12 hours; the nuclear translocation of nuclear factor-κB p65 (NF-κB p65) as well as the phosphorylation levels of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinases (p38MAPK), c-Jun N-terminal kinase (JNK), c-jun, c-fos were detected by Western Blot after 15 minutes, 30 minutes, 1 hour and 2 hours.Results ① The different proliferative potential of RAW264.7 treated with LPS (10 mg/L) and ELL (0.05, 0.5, 5μmol/L) had no significant difference comparing with control group, which indicated that ELL had no cytotoxicity with experimental concentration and had no effect on the cell proliferative potential as the result of drug interaction. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in supernatant were significantly increased after induced by LPS comparing with control group. However, the different concentrations of ELL could dose-dependently reverse the production of inflammatory factors, and 5μmol/L was the optimum concentration of anti-inflammatory. ② Compared with control group, the mRNA expressions of TNF-α, IL-6 were significantly increased, the nuclear translocation level of NF-κB p65 increased as well as the phosphorylation levels of ERK, p38MAPK, JNK, c-fos, c-jun after stimulated by LPS. While, the different concentration of ELL could reverse the mRNA of TNF-α, IL-6 and phosphorylation levels of JNK, c-fos, c-jun [TNF-αmRNA (2-&Delta;Ct) 2.45± 0.19 vs. 3.41±0.32 after 2 hours, 1.20±0.11 vs. 2.11±0.21 after 4 hours, 1.68±0.09 vs. 2.51±0.31 after 6 hours;IL-6 mRNA (2-&Delta;Ct) 3.41±0.52 vs. 4.10±0.38 after 6 hours, 1.61±0.08 vs. 3.91±0.25 after 12 hours; p-JNK/GAPDH0.557±0.034 vs. 1.049±0.056 after 1 hour, 0.439±0.040 vs. 0.855±0.038 after 2 hours; p-c-fos/GAPDH 0.158± 0.030 vs. 0.741±0.035 after 1 hour, 0.156±0.015 vs. 0.932±0.030 after 2 hours; p-c-jun/GAPDH 0.425±0.036 vs. 0.802±0.059 after 1 hour, 0.345±0.075 vs. 0.952±0.068 after 2 hours; allP < 0.05]. However, it had no significant effect on the nuclear translocation level of NF-κB p65 and the phosphorylation level of ERK and p38MAPK. Conclusion ELL inhibited the production of IL-6, TNF-α inflammatory factors in LPS-induced RAW264.7 cells through suppression the phosphorylation of JNK and activator protein-1 (AP-1).