Elastase in hyperpnea-induced guinea pig airway constriction

Abstract

Aerosolized elastase has been shown to produce airway constriction in guinea pigs. In this study, we examined whether endogenous elastase plays a role in isocapnic hyperpnea-induced airway constriction using an elastase inhibitor, eglin-c. The study was divided into three experiments. In the first experiment, we used an elastase inhibitor, eglin-c, to suppress hyperpnea-induced bronchoconstriction. Twenty-two young male Hartley guinea pigs were divided into three groups: control (n=8), eglin-c(1) (a lower dose of eglin-c, n=7), and eglin-c(2) (a higher dose of eglin-c, n=7). In the second experiment, we tested whether eglin-c affects pulmonary function following 15 min of normal air ventilation in two groups of animals: control (n=8) and eglin-c (n=8). In the third experiment, animals were divided into two groups: control (n=7) and compound 48/80 (a mast cell degranulating agent, n=7). Airway function was examined in the anesthetized–paralyzed animal. In the first and third experiments, 15 min of isocapnic hyperpnea caused marked decreases in dynamic respiratory compliance, forced expiratory flow at 0.1 s and maximal expiratory flow at 50% total lung capacity, demonstrating hyperpnea-induced airway constriction. This bronchoconstriction was significantly attenuated by eglin-c and by pretreatment with compound 48/80. In the second experiment, eglin-c did not significantly affect bronchial function following normal air ventilation. These data suggest that elastase released from mast cells directly or indirectly induces hyperpnea-induced bronchoconstriction.