Table 1. Blood gases, alveolar-arterial oxygen gradient, and lung / body weight ratio in the four experimental groups.^a .

Variable	Sham	Sham+MEL	BDL	BDL+MEL
ApO2	67±11.3	66.3±12.4	57.2±6.2	71±5.4
ApCO2	45±1.4	48±5.2	56.6±1.5*	48.2±4.5
SaO2	91±4.2	88.3±6.4	84.8±6.2	92.5±2.6
APO2	93.4±1.7	89.7±6.6	78.9±1.9*	89.4±5.7
D (A-a)O2 Pulmonary weight ratio/ body weight (%)	26.4±13 0.32±0.09	23.4±5.9 0.34±0,05	21.7±5.7 0.57±0.05**	18.4±11 0.37±0.02

BDL: Biliary Duct Ligature; Sham+MEL: Sham and melatonin; BDL+MEL: Biliary Duct Ligature and melatonin. ApO₂: Arterial Partial Oxygen Pressure; ApCO₂: arterial partial pressure of carbon dioxide; SaO₂: arterial oxygen saturation; APO₂: alveolar partial pressure of oxygen; and D (A-a)O₂: alveolar-arterial oxygen gradient. ^aResults expressed by average + standard deviation. *p <0.05 vs. group Sham, Sham + MEL, BDL + MEL. **p <0.01 vs. group Sham, Sham + MEL, HBL + MEL.