Fig. 1
Mechanical ventilation induces pulmonary inflammation and increases cerebral soluble Aβ1–40 in ADtg mice. a Schematic illustration of experimental design and timeline: 5-month-old ADtg and wild-type (WT) mice underwent mechanical ventilation (MV) with a tidal volume of 15 ml/kg for 4 h while control groups of ADtg and WT mice were spontaneously breathing (SB) (n = 8–12 mice per group). Mice recovered for 6 h and 30 min prior to perfusion, they received intravenous injections of Texas Red-dextran (3 kD) and FITC-dextran (2000 kD) tracers (0.25% each). Bronchoalveolar lavage (BAL) fluid specimens were analyzed for cell count, plasma and left hindbrains were collected for protein analysis (P), and the right brain hemispheres were isolated for histology (H). b Mean arterial oxygen saturation for ADtg and WT mice are presented for each hour of MV, analyzed by two-way ANOVA. c Percent of polymorphonuclear cells (PMNs), or neutrophils, in the BAL was measured for each group, ADtg and WT in both MV and SB conditions (n = 8–12 mice/group). d Sandwich ELISA analysis of human soluble Aβ1–42 levels in the brains of age-matched ADtg mice (n = 8–9 mice/group). e ELISA analysis of cerebral soluble Aβ1–40 levels in age-matched ADtg mice (n = 8–9 mice/group). f Pearson’s r correlation analysis between cerebral soluble Aβ1–40 and % PMNs in BAL in age-matched ADtg mice in both conditions, MV (orange dots) and SB (yellow dots) with 95% confidence interval (CI) in dashed lines. Data from individual mice and group means with standard error of measurements are shown, as well as p values (pi = p value for interaction; pMV = p value for MV intervention effect; pg = p value for genotype effect). Fold increases in MV compared to SB-control groups are shown in red. *p < 0.05, **p < 0.01, ****p < 0.0001, using two-way ANOVA with Holm-Sidak’s post hoc multiple comparisons correction, unpaired two-tailed Student t tests for two-group comparison, and Pearson’s correlation analysis