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

and CD62L. TLR2 and TLR4/myeloid differentiation factor 2 are vital in the recognition of LPS in the host, and the triggering of these receptors can lead to neutrophil recruitment and migration via CXCR1 and CXCR2. CD11b and CD62L, which are expressed on the surface of neutrophils, are critical for the occurrence of sepsis. LPS, also known as endotoxin, is a component of the outer membrane of Gram-negative bacteria, and is known to induce septic shock when present in high quantities. Therefore, the present study measured the expression of neutrophil chemokine receptors under LPS stimulation. The isolated neutrophils were treated with either vehicle or increasing concentrations (10, 100 and 1,000 ng/ml) of LPS for 4 h, and the expression levels of CXCR1, CXCR2, TLR2, TLR4, CD11b and CD62L were measured using flow cytometry. The results showed that LPS treatment resulted in decreased expression levels of CXCR1, CXCR2 and CD62L in a dose-dependent manner (Fig. 1A-C) , which was in accordance with the results of a previous study (23) . However, no significant changes were observed in the expression levels of TLR2, TLR4 or CD11b in the LPS-treated neutrophils, compared with the vehicle-treated neutrophils (Fig. 1D-F) . Therefore, the expression levels of TLR2, TLR4 and CD11b were not examined in the remainder of the experiments.