RESUMO
Objective To investigate whether astragaloside ( AST) Ⅳ could inhibit lipopolysac-charide (LPS)-induced activation of astrocytes and the possible mechanism. Methods Effects of different concentrations of AST Ⅳ on astrocyte viability were determined by MTT to select the optimum concentration for the following experiments. Primary astrocytes were induced by LPS to construct the inflammatory model. Astrocytes were divided into three groups: PBS, LPS and LPS+ASTⅣ(LPS+ASTⅣ) groups. The release of nitric oxide (NO) was detected by Griess method. Expression of glial fibrillary acidic protein ( GFAP), an astrocyte marker, and TLR4 were analyzed by immunohistochemistry and Western blot. Cytokines of IL-6, TNF-α, IL-4 and IL-10 in the supernatants of cell culture for 24 h collected after stimulation were meas-ured by ELISA. Results ASTⅣsignificantly inhibited the LPS-induced activation of astrocytes and NO re-lease (P<0. 01), suppressed the expression of TLR4 (P<0. 05) and reduced the secretion of IL-6 (P<0. 01) and TNF-α (P<0. 01), but increased the secretion of IL-4 and IL-10 (P<0. 05 and P<0. 01). Con-clusion AST Ⅳ could significantly inhibit the LPS-induced activation of astrocytes and suppress inflamma-tory responses, and the possible mechanism might be related to reduced secretion of inflammatory factors af-ter blocking the expression of TLR4.