Fig. 4.

Quercetin attenuates LPS-induced inflammatory response by inhibiting the NF-κB signaling pathway. Lamellar keratinocytes (passages 2–4) were pretreated with 10 µM PDTC for 1 h, then treated with LPS (10 µg/mL) and quercetin (25 µM). A-H The secretion of (A) TNF-α, (B) IL-6, (C) IL-1β, (D) IL-10, (E) CXCL-1, (F) CXCL-6, (G) COX-2, and (H) iNOS in cell supernatants was detected by ELISA. I-P The mRNA expression of (I) TNF-α, (J) IL-6, (K) IL-1β, (L) IL-10, (M) CXCL-1, (N) CXCL-6, (O) COX-2, and (P) iNOS was determined with RT-qPCR. The data are presented as mean ± standard deviation from three independent biological replicates. The symbol “+” in the diagram indicates the addition of a substance, while “-” denotes no addition. The symbol * indicates P < 0.05, and ** indicates P < 0.01