Figure 4.

Cigarette smoke extract (CSE) inhalation model. (a) Experimental schedule. CSE or PBS was intranasally administered 3 times per week for 8 weeks to 4-month-old ARF-DTR or wild-type mice. DT was intraperitoneally injected twice with a 2-week interval. (b) Representative images of an in vivo imaging analysis of luciferase expression. (c,d) The expression of (c) Arf and (d) Ink4a mRNA was analyzed by real-time PCR in the lung tissue of ARF-DTR or wild-type mice. Data were normalized to Gapdh in each group. Bars represent means ± SEM. Data were analyzed by a one-way ANOVA and Tukey post-hoc analysis. Student’s t-test was performed for the analysis of wild-type mice data and no significance was observed. * p < 0.05 and ** p < 0.01.