Lowering of Interstitial Fluid Pressure Will Enhance Edema in Trachea of Albumin-sensitized Rats

摘要

Interstitial fluid pressure (P_(if)) has recently been found to play an important role in edema formation in acute airway inflammation. Because airway inflammation is important in the pathogenesis of asthma, P_(if) was measured in rat trachea after albumin challenge to rats previously sensitized to chicken egg albumin. In pentobarbital anesthesia (50 mg/kg intraperitoneally) sensitized rats received an intravenous infusion of either saline or albumin, which circulated for 4 min. Circulatory arrest was then induced with saturated KCI intravenously to prevent further edema formation, which will increase P_(if) and thereby possibly cause an underestimation of an increased negativity of P_(if). P_(if) was measured with sharpened glass capillaries (diameter 3-6 μm) connected to a servo-controlled counter pressure system. P_(if) was -1.3 ± 0.4 mm Hg in controls and -5.8 ± 0.5 mm Hg in sensitized rats (p < 0.01) after allergen challenge. Airway resistance was measured to verify the occurrence of airway narrowing and increased significantly in sensitized rats after allergen challenge but did not change in controls. The experimental anti-inflammatory drug, α-trinositol (D-myo-inositol-1,2,6-trisphosphate, 10 mg), given before or after allergen challenge abolished the increased negativity of P_(if) (p < 0.05), while hydrocor-tisone (6.25 mg) had no effect. Thus, allergen challenge is associated with a lowering of P_(if), which was abolished by α-trinositol.