Paeoniflorin regulates the function of human peripheral blood mononuclear cells stimulated by rhIL-1β by up-regulating Treg expression.

The aim of the present study was to investigate the effect of paeoniflorin (Pae) on recombinant human interleukin-1β (rhIL-1β)-stimulated human peripheral blood mononuclear cells (PBMCs) in vitro. PBMCs were collected by Ficoll density gradient centrifugation and were co-cultured with rhIL-1β for different time periods. The proliferation response was determined by a cell counting kit-8 (CCK-8) assay. The production of IL-17 and IL-10 was measured by enzyme-linked immunosorbent assay (ELISA). The percentage of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg) was detected by flow cytometry analysis. These results indicated that rhIL-1β stimulation induced the proliferation of PBMCs in a concentration- and time-dependent manner; it also increased the level of IL-17 and decreased the level of IL-10 in a concentration-dependent manner. The flow cytometry analysis demonstrated that the stimulation of rhIL-1β significantly downregulated the percentage of CD4(+)CD25(+)Foxp3(+) Treg in CD4(+) T cells. However, administration of Pae significantly suppressed the proliferation response of rhIL-1β-induced PBMCs and regulated the secretion function of IL-17 and IL-10. Additional experiments demonstrated that Pae treatment significantly reduced rhIL-1β-induced decreases in PBMCs CD4(+)CD25(+)Foxp3(+) subpopulation numbers. These results suggest that the anti-inflammatory action of Pae is attributable to its regulation of IL-17/IL-10 secretion and Treg expression.