[Histological and histochemical changes of tracheal secretory cells following bromhexine treatment (author's transl)]

The effects of bromhexine, a mucolytic agent, on secretory activities of canine tracheal secretory cells and on behaviour of glycoprotein in these secretory cells were investigated histologically and histochemically. Following bromhexine treatment, the number of total glycoprotein-containing goblet cells (GC) remained the same. The number of acid glycoprotein (AGP)-containing GC was reduced concentration-dependently, while neutral glycoprotein (NGP)-containing GC significantly increased with doses of 10-6, 10-5 and 10-4M. The number of sulphated glycoprotein (SGP) in AGP-containing GC decreased concentration-dependently. Acinar inner diameter of the submucosal gland and an acinar inner diameter of this gland to wall ratio (AIWR) increased with doses of 10-5 and 10-4M. Particularly, AIWR significantly increased with dose of 10-4M. Thickness of the acinus tended to slightly decrease concentration-dependently. AGP content in glandular cells decreased, while NGP content in these cells markedly increased, concentration-dependently. SGP content in the glandular cells decreased. Total saccharide and protein concentrations in the incubation fluid significantly increased with higher concentrations of the treatment, whereas N-acetylhexosamine slightly decreased concentration-dependently. These findings suggest that bromhexine does not enhance secretory activities of GC, but does stimulate the activities of the submucosal glands, when the drug is given in higher concentrations. Bromhexine markedly dissolves AGP in granules of the secretory cells.