Effect of fudosteine, a cysteine derivative, on blood flow of tracheal microvasculature increased by airway inflammation

We examined the effect of fudosteine, a cysteine derivative, on blood flow of tracheal microvasculature increased by airway inflammation. Airway infla mmation was elicited by sulfur dioxide (SO2) exposure for 2 weeks in rabbit s. Each drug (500 mg/kg, p.o.) or 0.5% carboxymethylcellulose-Na (control g roup) was daily administered just before SO2 exposure. After final SO2 expo sure was finished, blood flow of tracheal microvasculature was measured by blood perfusion monitor. Fudosteine or S-carboxymethylcysteine (S-CMC) sign ificantly suppressed blood flow of tracheal microvasculature increased by S O2 exposure. However, no effect of fudosteine was observed on the pharmacol ogical microvascular response in trachea of SO2-exposed rabbits. On the oth er hand, fudosteine or S-CMC scavenged superoxide anion generated from rat neutrophils, and enzymatically generated from xanthine oxidase-acetaldehyde reaction. The results suggest that suppressive action in increased trachea l blood flow of fudosteine is due to anti-inflammatory activity, at least i n part, via scavenging of superoxide anion. (C) 2001 Elsevier Science B.V. All rights reserved.