Fig. 1

Respiratory responsiveness to methacholine expressed as area under the curve (AUC) of the resistance (R) 24 h after intranasal instillation of AP or vehicle (saline). Experimental groups were DMSO/SAL and AP/AP and were consisted in 5–8 mice per group. First abbreviation refers to dermal sensitization (day 1 and 8), and the second to the agents administered via intranasal instillation (day 15, 22, 29, 36, 45, 60, 90). a Mean ± SD of AUC of R against methacholine concentrations (0–20 mg/ml). b Mean individual values of AUC at 15, 36, 60 and 90 days after challenge. *p < 0.05, **p < 0.01 compared with DMSO/SAL. AHR airway hyperresponsiveness; AP ammonium persulfate; AUC area under the curve; DMSO dimethylsulfoxide; SAL saline