Objective: 

In vitro, the pro-oxidant agents have been reported to induce constriction of the airway smooth muscle. The aim of this paper was to study the effect of cumene hydroperoxide and hypochlorite on the tracheal smooth muscle in vitro.

Methods: 

There were 12 spiral trachea obtained from male Wistar rats (200 g). A dose-response curve was performed using acetylcholine concentrations from 10-5 to 10-6 M. After 5 doses response curves and a washing period, samples were incubated for 30 minutes with hypochlorite (10-3 M), respectively cumene hydroperoxide (10-4 M) and a new acetylcholine dose-response curve was performed. For each study we have performed 4 to 6 experiments. Statistical analysis included calculation of mean values, standard deviation and Student's t-test.

Results: 

The hypochlorite enhanced the acetylcholine constrictor effect (29.2 ±3.7%; p<0.001) for all doses of acetylcholine. Incubation with cumene hydroperoxide enhanced the acetylcholine constrictor effect (36.5 ±1.3%; p<0.001), but only for intermediate doses of acetylcholine. The maximal effect of acetylcholine dose response curve did not change significantly.

Conclusions: 

The possible mechanism involved in hyperconstriction induced by cumene hydroperoxide is mediated by distruction of epithelial layer.