Effect of terbutaline on alveolar liquid clearance after oleic acid-induced lung injury in rats.
OBJECTIVE
To investigate whether terbutaline affects alveolar liquid clearance after oleic acid-induced lung injury in rats.


METHODS
Forty healthy Wistar rats (weighing 250-280 g) were randomly divided into five groups (n=8 in each group): the normal control group (control group), oleic acid injury group (injury group), terbutaline-treated group (terbutaline group), terbutaline plus amiloride-treated group (terbutaline+amiloride group) and terbutaline plus ouabain-treated group (terbutaline+ouabain group). Acute lung injury model was induced by intravenous oleic acid (0.25 ml/kg body weight). 24 hours later, 1.5 microCi (125) I-labeled 5% albumin solution (5 ml/kg body weight) was dripped into the lungs through trachea. The alveolar liquid clearance rate, extravascular lung water content, and arterial blood gas were measured 1 hour thereafter.


RESULTS
At 24 hours after infusion of oleic acid, the rats developed pulmonary edema and severe hypoxemia, with the alveolar liquid clearance rate decreased by 49.2% and the extravascular lung water content elevated by 47.9%. Compared with the rats in the injury group, terbutaline (10(-4) mol/L) significantly increased the alveolar liquid clearance rate, decreased the extravascular lung water content and improved hypoxemia. The effect of terbutaline was partly blocked by amiloride and ouabain, which were inhibitors of sodium transport. Terbutaline increased the alveolar liquid clearance rate by 63.7%, and amiloride and ouabain reduced the alveolar liquid clearance rate by 54.7% and 56.8%, respectively.


CONCLUSIONS
Terbutaline can accelerate alveolar liquid clearance through increasing sodium transport to attenuate pulmonary edema, thus improving gas exchange, which may have therapeutical effect on pulmonary edema after acute lung injury.
Tao
Jun
J
Department of Anesthesiology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China. xqtj0560@sina.com
Yang
Tian-de
TD
Li
Hong
H
Du
Zhi-yong
ZY
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001784:Blood Gas Analysis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015633:Extravascular Lung Water / Q000187:drug effects; D006801:Humans; D008171:Lung Diseases / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors; D013726:Terbutaline / Q000494:pharmacology*
D000318:Adrenergic beta-Agonists; D004791:Enzyme Inhibitors; D010042:Ouabain; D000584:Amiloride; D000254:Sodium-Potassium-Exchanging ATPase; D013726:Terbutaline