Abstract: ［Abstract］〓Objective〖HTSS〗〓To investigate the effect of extracellular regulated protein kinases(ERK) pathway on apoptotic cells inhibiting lipopolysaccharides(LPS) induced inflammatory CC chemokine ligand 5(CCL5) secreted by macrophages.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓Apoptotic cells were prepared by Jurakt cells and the apoptosis rate was detected by flow cytometry. Bone marrow induced macrophages(BMDM) and RAW264.7 cells were stimulated by LPS to observe the effect of apoptotic cells on the expression of CCL5 induced by LPS. To observe the role of ERK pathway in inhibiting CCL5 expression in apoptotic cells, RAW264.7 cells were transfected with control plasmids PcDNA3.1, MEKK2/3 and MEK5. The cells were treated with LPS(1 mg/L), apoptotic cells(apo) and LPS(1 mg/L) + apo for 6 hours respectively. The expression of CCL5 mRNA was detected by realtime quantitative PCR. The ERK pathway was blocked and the expression of CCL5 mRNA was observed.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓The expression of CCL5 mRNA in LPS stimulation group and LPS + apoptotic cell stimulation group was significantly higher than that in blank group and apoptotic cell stimulation group. The expression of CCL5 mRNA in LPS + apoptotic cell stimulation group was significantly lower than that in LPS stimulation group(P＜0.05). The expression of CCL5 mRNA in PD98059 5 mmoL/L, 10 mmoL/L, 20 mmoL/L group was lower than that in DMSO group, the expression of CCL5 mRNA in PD98059 10 mmoL/L, 20 mmoL/L group was lower than that in PD98059 5 mmoL/L group, and the expression of CCL5 mRNA in PD98059 20 mmoL/L group was lower than that in PD98059 10 mmoL/L group(P＜005). CCL5 mRNA levels in PcDNA3.1 transfection group, MEKK2/3 transfection group and MEK5 transfection group were significantly higher than those in control group, MEKK2/3 transfection group and MEK5 transfection group were significantly higher than those in PcDNA3.1 transfection group, and CCL5 mRNA levels in MEK5 transfection group were significantly higher than those in MEKK2/3 transfection group(P＜005). The decay rate of CCL5 mRNA in group D98059 was faster than that in blank group(P＜005).
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓Apoptotic cells can inhibit the expression of CCL5 induced by LPS, and ERK signaling pathway plays an important role in the inhibition of CCL5 expression by apoptotic cells.

Key words: chemokines, lipopolysaccharides, extracellular regulated protein kinases pathway