Table 1. Ventilator-induced lung injury (VILI) score in each experimental groups.

Group	Alveolar congestion	Hemorrhage	Neutrophil infiltration	Alveolar wall thickness	Total score
Sham	2.78±0.97	0.44±0.53	0.33±0.50	0.22±0.44	3.78±0.67
VILI	3.44±0.88	1.00±0.71	1.22±0.44	1.33±1.58	7.00±1.41a
Sivelestat	3.78±0.44	1.00±0.71	0.67±0.71	0.89±0.93	6.33±1.41b
Early sivelestat	3.44±0.88	0.56±0.53	0.89±0.33	0.11±0.33	5.00±0.50c

Data are presented as mean ± standard deviation. Acute lung injury was scored in each sample according to the following four items: alveolar congestion, hemorrhage, infiltration or aggregation of neutrophils in airspace or the vessel wall, and thickness of the alveolar wall. A score of 0 represented normal findings and scores of 1, 2, 3 and 4 represented mild (<25%), moderate (25-50%), severe (50-75%) and very severe (>75%) lung involvement, respectively. The overall score was based on the sum of all scores. ^a, P<0.001 between sham and VILI; ^b, P=0.326 between VILI and sivelestat; ^c, P=0.023 between sivelestat and early sivelestat.