Fig. 1.

Overview of tissue traction microscopy to elucidate airway smooth muscle (ASM) contraction. A: schematic of the experimental setup. Shown in inset are representative images of ASM and airway in precision-cut lung slices (PCLS) (top right) and surface-bound fluorescent beads (top left). Red box indicates the region of interest. B: adhesion of the PCLS to the substrate does not change (P = 0.48, paired t test) the magnitude of airway constriction with 10⁻⁴ M ACh at 30 min (each airway was imaged pre- and postadherence; shown are pre/post values for each airway as individual connected points). C: representative bright-field images and overlaid stress maps in response to 10⁻⁴ M ACh (30 min) and 10⁻³ M chloroquine (ChQ; 25 min). Scale bar = 500 μm. D and E: time-dependent lumen area changes (gray line) and ASM contraction changes (black line) in response to 10⁻⁴ M ACh followed by 10⁻³ M ChQ. D: the lumen area for each airway is normalized to its pretreatment baseline value. E: both lumen area and ASM contractile moment are normalized to the value at 10⁻⁴ M ACh at 30 min, denoted in the plot as “max ACh.” All data are reported as average and SD (n = 13 airways). *P < 0.001 (F-test two samples for variance).