Fig. 2.

Effects of arctiin on H9N2 avian influenza virus (AIV)-induced inflammation. A549 cells infected with H9N2 AIVs (MOI = 0.1) were treated with or without arctiin (100–300 μg/mL) for 24 h. The cells were lysed by TRIzol to assess the mRNA levels of proinflammatory cytokines (A) and COX-2 (C). Protein levels of proinflammatory cytokines (B) in the culture supernatants and COX-2 expression (D) were measured by ELISA and western blot analysis, respectively. E Band intensities of COX-2 in (D) were normalized to GAPDH by densitometric analysis using ImageJ software. F The concentration of PGE₂ in the culture supernatants was measured by ELISA. The results are expressed as means ± SD. ^##p < 0.01; ^###p < 0.001 compared with the control group; ^*p < 0.05; ^**p < 0.01 compared with H9N2 virus infection alone