Comparison of the Effect of Aerosols of Saline and Mineral Water on the Tracheal Epithelium

Konrádová V. , L. Vajner , J . Uhlík, J . Zocová: Comparison of the Effect of Aerosols of Saline and Mineral Water on the Tracheal Epithelium. Acta Vet. Brno 2003, 72: 151-156. Ultrastructure of the airway epithelium and character of glycoconjugates produced by secretory cells were studied after 10-min inhalations of saline and mineral water aerosols. Methods of electron microscopy and conventional and lectin histochemistry were used. The results were evaluated quantitatively. The target cells for the function of both aerosols were the goblet cells. These cells were overstimulated and the mechanism of mucus evacuation was accelerated. The exhausted goblet cells mostly took part in further secretory cycles. The cells not entirely filled with secretory granules prevailed in the epithelium. Massive differentiation of new secretory elements caused changes in the secretory cells’ distribution. Of the two aerosols, only mineral water induced significant changes in the composition of glycoconjugates in the secretion of goblet cells. Due to administration of saline, the ciliated cells were less damaged. The percentage of altered cilia was significantly lower compared with that after mineral water inhalation. Morphological signs of impaired self-cleaning ability of the airway epithelium were discovered only after mineral water inhalation. From the morphological point of view, administration of saline aerosol is less harmful compared with that of mineral water. Airways, ciliated cells, goblet cells, electron microscopy, lectin histochemistry, inhalation In our preceding study, we demonstrated that single 10-min inhalation of mineral water aerosol overstimulated secretory elements in the tracheal epithelium. Changes in the character of secreted glycoconjugates (GCs) were also recorded (Konrádová et al. 2001). We therefore decided to investigate also the effect of inhalation of saline aerosol and to compare it with that produced in the epithelium by inhalation of mineral water. Materials and Methods In our experiments, 19 SPF New Zealand White rabbits (body weight 1,500-3,000 g, Charles River Deutschland, Sulzfeld, Germany) were used. Seven of them served as untreated controls. The remaining animals were placed successively for 10 min into a plastic cage connected with the inhalation device PARI Master and nebuliser PARI LL (Pari GmbH, Starnberg, Germany, medium diameter of produced droplets 3.1 m m, total output 0.6 g/min). Six rabbits inhaled an aerosol of saline; another six rabbits were treated with an aerosol of natural hypertonic iodinated spring water (osmolarity 331 mOsm, pH 6.48). The chemical composition of the spring water was specified in our previous study (Konrádová et al. 2001). The material for electron microscopic and histochemical examinations was collected under general anaesthesia immediately post exposure. Tiny fragments of the tracheal mucous membrane were fixed for 90 min with 5% glutaraldehyde in cacodylate buffer (pH 7.2) and then for 60 min with 2 % OsO4 in cacodylate buffer (pH 7.4), dehydrated in graded series of alcohol and embedded in a Durcupan-Epon mixture. Ultrathin sections were prepared on Ultrotome Nova (LKB, Broma, Sweden), contrasted with uranyl acetate and lead citrate and examined under the JEM 100 C electron microscope (Jeol, Tokyo, Japan). In the formalin-fixed and paraffin-embedded material, the methods of conventional histochemistry (Alcian Blue /AB/ pH 2.5 PAS and AB pH 1.0) as well as of in situ lectin histochemistry, described in detail in our previous study (Vajner et al. 2000), were employed. Maackia amurensis agglutinin MAA, Sambucus nigra agglutinin SNA