Figure 2.

Early-life exposure to CS alters sensitivity to methacholine up to 13 wk after cessation of smoke exposure. Lung function parameters: total lung resistance at baseline (A) and airway resistance at baseline (B). Female offspring exposed to prenatal CS had significantly higher Rn (mean = 0.34, SD = 0.03) compared with female controls (mean = 0.26, SD = 0.06). C: tissue resistance at baseline. D: alveolar elastance at baseline. Male offspring exposed to prenatal CS had significantly higher H (mean = 17.50, SD = 0.63) compared with male controls (mean = 16.40, SD = 0.91). E: total lung resistance with methacholine. F: airway resistance with methacholine. G: tissue resistance with methacholine. H: alveolar elastance with methacholine. Lung function with methacholine (E–H): *P < 0.05, control versus full CS; †P < 0.05 control versus postnatal CS; #P < 0.05 control versus prenatal CS groups. Group numbers: control females = 6, postnatal females = 7, prenatal females = 5, full females = 9, control males = 7, postnatal males = 8, prenatal males = 9, full males = 6. Lung function was assessed by taking 90th percentile values in response to injection of saline into the lungs (baseline) and in response to increasing doses of methacholine. Lung function data were analyzed in a sex-disaggregated manner using a two-way ANOVA, followed by multiple comparisons between groups at each methacholine dose where significant. CS, cigarette smoke; H, elastance; Rn, Newtonian resistance.