Fig. 2. Rats (n = 11–15) were injured with hydrogen chloride (the acid group) or acidified gastric particles (the casp group) and then exposed to air, nitric oxide (80 ppm) in air, 90% oxygen, or (80 ppm nitric oxide) in 90% oxygen for 5 h. Lung injury was assessed according to (  A ) pulmonary microvascular protein leakage (permeability index) and (  B ) the lung wet–dry weight ratio. Data are presented as the mean ± SD, and statistical significance is shown by asterisks.