Change of alveolar liquid clearance capacity following acute lung injury induced by oleic acid

Objective To explore the change of alveolar epithelial liquid clearance capacity in lung edema following acute lung injury induced by oleic acid.Methods Forty-eight Wistar rats were randomly divided into 6 groups: the control(C), injury(I), amiloride(A), ouabain(O),amiloride plus ouabain(AO), and terbutaline(T) groups. Acute lung injury was induced with intravenous oleic acid 0.25 mlkg -1. 24h after injury, 5% albumin solution (5 ml·kg -1) was delivered into both lungs via the trachea in C and I groups. In A, O, AO and T groups, amiloride (2×10 -3 mol/L),ouabain (5×10 -4 mol/L), amiloride (2×10 -3mol/L) and ouabain (5×10 -4 mol/L)mixture and terbutaline(10 -4 mol/L),added respectively to the albumine solution,at 5ml.kg -1 were administered intratracheally to both lungs separately. One hour later, the alveolar liquid clearance rate(ALC), total lung water content(TLW), extravascular lung water content(EVLW) and arterial blood gases were measured.Results As compared with those in C group, severe hypoxemia, hypercapnia and acidosis appeared, ALC was reduced by 49.2% ,TLW and EVLW markedly increased in I group(P0.01).Compared with those in I group, ALC decreased much more , TLW and EVLW further rose in A,O and AO groups(P0.05 or 0.01),but ALC increased by approximately 63.7%, TLW and EVLW greatly decreased(P0.01), and hypoxemia was improved in T group. A significant negative correlation was found between TLW or EVLW and ALC.Conclusions The alveolar epithelial liquid clearance capacity may be play an important role in the pathogenesis of lung edema following acute lung injury.