Effect of brovanexine on secretory activities of tracheal secretory cells

Abstract

The expectorant effect of brovanexine (BvX) was investigated histologically and histochemically using isolated canine trachea. Following BvX treatment, the number of goblet cells (GC) stained positively with the combination procedure of alcian blue at pH 2.5 or pH 1.0 and periodic acid-Schiff was unaffected. The number of GC which stained blue and purple (stain index B & P) was reduced, while the number of GC that stained red (stain index R) was increased. The thickness of the acini of submucosal glands (SG) markedly decreased with 10^-5 and 10^-4M BvX, and the ratio of the acinar inner diameter to the tracheal wall thickness significantly increased with 10^-4M BvX. Stain index B & P of glandular cells decreased with 10^-5 and 10^-4M BvX, which was accompanied by a marked increase in the stain index R. BvX treatment caused increases in total saccharide and protein concentrations in the incubation fluid, while N-acetylhexosamine slightly decreased. Both the BvX-induced histological changes in glandular cells and changes in concentrations of macromolecular components in the incubation fluid were much the same degree as those induced by bromhexine (Bh). The BvX-induced histochemical changes in secretory cells, however, were slighter than those induced by Bh. These findings suggest that BvX is an expectorant possessing both the secretagogic action selectively on SG and a mucolytic action toward acid glycoproteins in granules of secretory cells.