n-butanol extract from Folium isatidis inhibits the lipopolysaccharide-induced downregulation of CXCR1 and CXCR2 on human neutrophils

Wu, Beibei; Wang, Liyin; Jiang, Lili; Dong, Lili; Xu, Fengli; Lu, Yili; Jin, Jiahui; Wang, Zhanyue; Liang, Guang; Shan, Xiaoou

IL-8 is a ligand of CXCR1 and CXCR2, and is rapidly secreted upon cell stimulation. The mRNA expression of IL-8 significantly increased upon stimulation with LPS (Fig. 4A) . However, n-butanol extract decreased the expression of IL-8 in a dose-dependent manner ( Fig. 4B and C) , and prevented the decreases in the expression of CXCR1 and CXCR2. This suggested that the extract increased the activity of neutrophils and upregulated the expression of chemokine receptors, including CXCR1 and CXCR2, rendering neutrophils more sensitive to the ligand IL-8. The present study quantified MPO activity as a measure of neutrophil migration. It was found the extract promoted the activity of MPO. The extract also promoted the ability of neutrophils to migrate by increasing the expression of CXCR1 and CXCR2 on the surface of neutrophils.