[Preliminary experimental research on glucocorticoid for treatment of nitrogen dioxide induced acute pulmonary edema in rats].
OBJECTIVE
To investigate the therapeutic effect of glucocorticoids on the acute pulmonary edema in rats induced by nitrogen dioxide (NO₂).


METHODS
Thirty SD female rats were randomly equally divided into 5 groups: normal control group, NO₂ exposed group, high-, middle- and low-dose of glucocorticoids treated group (6 rats per group). 6 rats in the normal control group were exposed to room air for 30 min, and the other rats to NO₂. 18 rats in the glucocorticoids group were treated with different doses of dexamethasone (6.0, 3.0, 1.0 mg/kg), while the rats in the NO₂ poisoning group were treated with normal saline (2.5 mg/kg). The lung wet/dry (W/D) weight ratio was calculated, and plasma atrial natriuretic peptide (ANP) levels, superoxide dismutase (SOD) activity from whole blood, plasma interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor-α (TNF-α) and Interferon-γ (IFN-γ) were detected by enzyme-linked immunosorbent assay (ELISA).


RESULTS
The lung W/D ratios were increased significantly in glucocorticoids treated group and NO₂-exposed group compared with normal control group (P < 0.05), while they were significantly reduced in glucocorticoids treated group as compared with NO₂-exposed group (P < 0.05). SOD activity in whole blood in glucocorticoids treated group and NO₂-exposed group was significantly lower than that of normal control group (P < 0.05), while it was no significant difference between that of glucocorticoids treated group and NO₂-exposed group (P > 0.05). Plasma ANP was significantly increased in NO₂-exposed group compared with normal control group (P < 0.05), while it was significantly decreased in glucocorticoids treated group compared with NO₂-exposed group (P > 0.05). Plasma TNF-α of high-, middle- and low-dose of glucocorticoids treated group [(27.04 ± 8.19), (40.10 ± 9.09), (39.76 ± 9.60) pg/ml] was decreased significantly as compared with NO₂-exposed group (68.55 ± 27.84 pg/ml) (P < 0.05). Plasma IL-6 in high- and middle-dose of glucocorticoids treated group [(15.97 ± 6.18), (19.69 ± 5.52) pg/ml] was significantly decreased as compared to NO₂-exposed group [(29.29 ± 9.31) pg/ml] (P < 0.05). Plasma IL-10 in high-, middle- and low-dose of glucocorticoids treated group [(23.24 ± 5.14), (27.78 ± 8.17), (33.29 ± 10.42) pg/ml] was significantly reduced compared with NO₂-exposed group [(44.38 ± 9.19) pg/ml] (P < 0.05). Plasma IFN-γ in high- and middle-dose of glucocorticoids treated group [(7.21 ± 4.55), (19.23 ± 4.35) pg/ml] was reduced compared with NO₂-exposed group [(30.83 ± 6.82) pg/ml] (P < 0.05).


CONCLUSIONS
High-, middle-, low-dose glucocorticoids all can improve the permeability of alveolar wall and capillary, and have nonspecific anti-inflammatory effects. The therapeutic effects on pulmonary edema are significant. High and middle dose of glucocorticoids treated group are more useful for decreased inflammatory factors.
Shanghai Pulmonary Hospital, Tongji University, Shanghai 200433, China.
Xun-miao
XM
Zhang
Dao-yuan
DY
Sun
Liang
L
Tang
Yan-jun
YJ
Yuan
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use*; D009585:Nitrogen Dioxide / Q000633:toxicity*; D011654:Pulmonary Edema / Q000139:chemically induced / Q000188:drug therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley
D005938:Glucocorticoids; D009585:Nitrogen Dioxide