小檗碱通过ERK,JNK信号转导途径对COX-2的抑制作用

Berberine inhibits lipopolysaccharide induced COX-2 expression via ERK signaling cascade pathways in human peripheral blood monocytes

目的:研究中药小檗碱是否通过ERK,JNK信号转导途径抑制人外周血单核细胞COX-2mRNA及蛋白表达.方法:取人外周静脉血分离及培养单核细胞,分为对照组、LPS组、LPS+小檗碱25μmol/L组、LPS+小檗碱50μmol/L组、LPS+小檗碱100μmol/L组.分别在培养后30min,6,12,24h提取细胞,行RT-PCR法测定COX-2mRNA水平,行Western Blot法测定ERK,p-ERK,JNK,p-JNK及COX-2蛋白水平.同时加入选择性ERK,JNK抑制剂,分别测定COX-2mRNA及蛋白水平.结果:与LPS组相比,小檗碱组COX-2mRNA及蛋白表达明显抑制(P<0.05).与LPS组相比,小檗碱组ERK活性水平有统计学差异(P<0.05).但是与LPS组相比,低、中浓度小檗碱组(25,50μmol/L)JNK活性水平无统计学差异,高浓度小檗碱组(100μmol/L)JNK活性水平有明显统计学差异(P<0.05).加入ERK,JNK抑制剂之后,COX-2mRNA及蛋白水平降低明显(P<0.05).结论:小檗碱能抑制人外周血单核细胞COX-2mRNA及蛋白水平,其作用程度呈浓度依赖性.小檗碱可能通过ERK信号转导途径抑制人外周血单核细胞COX-2mRNA及蛋白表达.高浓度小檗碱可能通过JNK信号转导途径抑制人外周血单核细胞COX-2mRNA及蛋白表达.

AIM： To investigate the inhibition of berberine （BBR） on lipopolysaccharide （LPS）induced COX-2 expression via ERK signaling cascade pathways in human peripheral blood monocytes（HPMC）. METHODS： HPMC were isolated and cultured from whole blood and divided into 5 groups treated with null, LPS, LPS ＋ BBR 25 μmol/L, LPS ＋ BBR 50 μmol/L, LPS ＋ BBR 100 μmol/L respectively for 30 rain, 6,12 and 24 h. Then monocytes were extracted for RT-PCR and westernblot analysis to examine COX-2 mRNA and protein activated expression of ERK signaling pathway. Meanwhile, ERK and inhibitor was incubated together with LPS stimulation to examine COX2 mRNA and protein expression. RESULTS： At the four time points after treatment, the COX-2 mRNA and protein expression decreased at a low ebb at 12 h after BBR treatment（P 〈 0.05）. In the group of BBR treatment at various time points （ at 6,12,24 h after treatment） and three levels of dosage, ERK protein expression was inhibited significantly. At the concentration of 25 and 50 μmol/L, JNK protein expression was not inhibited significantly by BBR compared with LPS stimulation group （ P 〉 0.05 ）. Whereas with the treatment of BBR at the concentration of 100 μmol/L, JNK protein expression could be inhibited obviously compared with LPS stimulation group （ P 〈 0.01 ）. Hmnan monoeytes COX-2 mRNA and protein expression was inhibited statistically significantly while incubated with ERK and JNK pathway inhibitor, PD98059 （P 〈 0.01）. CONCLUSION： We conclude that BBR inhibits COX-2 mRNA and protein expression in a dose-dependent manner and ERK expression could be suppressed by BBR. BBR may inhibit COX-2 expression via ERK signaling pathway in HPMC. High concentration of BBR may inhibit COX-2 expression via JNK sig- naling pathway in HPMC.