Figure 8. Nicotine inhibited the inflammatory response induced by H9N2 infection in vitro and in vivo.

A) Nicotine suppressed the H9N2-induced production of cytokines and chemokines in primary human macrophages. Primary human macrophages were pre-treated with 10 µM nicotine for 72 h, and then infected with H9N2 virus. Data represent 4–5 independent experiments. ^## p<0.01 and ^### p<0.001 were tested by ANOVA of three groups; *p<0.05 was determined by Tukey post hoc test. B) Body weight changes of nicotine treated mice after H9N2 virus infection. The mice were pre-treated with nicotine subcutaneously for 21 days and then infected by H9N2 virus. There were 5 mice per group. Data are representative of two independent experiments. ***p<0.001 was examined by multiple regression analysis adjusted for time. C) Lung virus titers of nicotine treated mice at indicated time points after H9N2 infection. There were 4 mice per group. D) Production of cytokines and chemokines in the lung homogenates from nicotine treated mice after H9N2 virus infection. There were 4–5 mice per group. *p<0.05 and **p<0.01 were performed by unpaired two-tailed Student's t test. Results represent mean ± SEM.