Figure 4

Poly(I:C) induces impairment of lung function and AHR. Mice were administered PBS or 10, 20, 50 or 100 μg polyI:C (I.N.) every 24 h for three days. 24 h after the last poly(I:C) administration, baseline lung function and AHR to increasing doses of methacholine was measured by whole body plethysmography (A & B). The 100 ug poly I:C group had higher penh levels than the PBS, 10, and 20 ug groups, p < 0.05 (B). Methacholine challenge resulted in a larger increase from baseline in the poly(I:C)-treated groups than in the PBS group, p < 0.001 for each methacholine dose. Invasive measurements of lung function were performed 24 h following three administrations (24 h apart) of 100 μg poly(I:C) (C). Peak airway resistance after i.v. injection of methacholine at 240 ug/kg are shown. Methacholine challenge resulted in a larger increase from baseline in the poly(I:C)-treated group than in the PBS group, p = 0.015. Repeated measures ANOVA was used to assess the Penh values over increasing methacholine doses as well as to compare increases in resistance in response to methacholine from baseline among the groups. Data are the mean ± SEM of 5–7 mice.