Abstract: Abstract: Objective To investigate the effects of total flavonoids of chrysanthemum indicum (TFC) on inflammatory response and autophagy of HK-2 cells induced by lipopolysaccharide (LPS), and to explore its possible mechanism. Methods HK-2 cells of human renal tubular epithelium were cultured in vitro and divided into control group, LPS treatment group, TFC pretreatment group, NLRP3 activator (4-MET) group and TFC combined with 4-MET pretreatment (TFC+4-MET) group. CCK-8 method was used to detect cell proliferation, Hoechst 33342 staining was used to observe the morphological changes of cells in each group. The expressions of apoptosis-associated speek-like protein containing CARD (Asc), caspase-1, p-IκB, IκB, autophagy-related protein (Beclin1), microtubule-related protein light chain 3Ⅱ (LC3Ⅱ)/ LC3Ⅰ were detected by Western blot assay. The levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18) were detected by ELISA method, and autophagy was observed by transmission electron microscopy. Results Compared with the control group, the proliferation rate decreased in LPS group, the fragmentation of cell nucleus increased, the apoptosis rate increased, the expressions of NLRP3, Asc, caspase-1 protein, the phosphorylation level of IκB protein increased, the levels of IL-1 β and IL-18 increased, and the expressions of LC3Ⅱ/Ⅰ and Beclin-1 protein decreased (P＜0.05). Compared with LPS group, cell proliferation rate increased in TFC group, cell nuclear fragmentation decreased, apoptosis rate decreased, NLRP3, Asc, caspase-1 protein expression and IκB protein phosphorylation level decreased, IL-1β and IL-18 levels decreased, autophagy increased, LC3 Ⅱ/Ⅰ level and Beclin-1 protein expression increased. The cell proliferation rate decreased in 4-MET group, apoptosis rate and nuclear fragmentation increased. The expression levels of NLRP3, Asc, caspase-1, IκB protein phosphorylation, IL-1β and IL-18 increased, autophagy, LC3Ⅱ/Ⅰ and Beclin-1 protein decreased (P＜0.05). The cell proliferation rate, autophagy degree, LC3 Ⅱ/Ⅰ level and Beclin-1 protein expression were higher in TFC+4-MET group than those in 4-MET group. The nuclear fragmentation was reduced, the apoptosis rate, NLRP3, Asc, caspase-1 protein expression, I κ B protein phosphorylation, IL-1 β and IL-18 levels were lower in TFC+4-MET group than those in 4-MET group (P＜0.05). Conclusion Total flavonoids of chrysanthemum indicum may inhibit the activation of NLRP3-IL-1β - NF - κB signaling pathway, thereby inhibiting the inflammatory response of HK-2 cells induced by lipopolysaccharide and inducing autophagy.

Key words: gout, lipopolysaccharides, autophagy, interleukin-1β, nuclear factor κB, total flavonoids of chrysanthemum indicum, nucleotide binding domain-like receptor protein 3, HK-2 cells