Table I.

Superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels in the lung tissue of rats in groups A-D.

Indices	Group A	Group B	Group C	Group D
SOD (U/g)	3.57±0.67	3.33±0.56	2.74±0.54a	2.56±0.48a
MDA (mmol/g)	0.97±0.47	1.12±0.56	1.37±0.62a	1.52±0.74a

Group A, normal group; group B, acute pulmonary edema model induced by hypoxia for 24 h; group C, acute pulmonary edema model induced by hypoxia for 48 h; and group D, acute pulmonary edema model induced by hypoxia for 72 h.

^aP<0.05, as compared with group A.