Ultrastructure of the aqueous lining layer in hamster airways: Is there a two-phase system?

Vajner²,

Uhlı́k³

et al. 2001

Acta Vet. Brno

In experiment, the effect of repeated inhalations of mineral water aerosol on the airway epithelium was investigated. Six rabbits inhaled mineral water for 10 min 5× in the course of 5 days, seven animals served as untreated controls. The tracheal mucous membrane was processed using standard methods of transmission electron microscopy; the results were evaluated quantitatively. In paraffin-embedded material, the methods of conventional and lectin histochemistry were employed. Due to the contact with mineral water aerosol, the goblet cells were overstimulated and the mechanism of secretion was accelerated. The exhausted goblet cells represented 66 ± 2%. High level of goblet cells' stimulation resulted in changes in their distribution in the epithelium. Small intraepithelial mucous glands were formed by 33 ± 4% of goblet cells. Goblet cells containing neutral glycoconjugates disappeared. A significant (α = 0.01) increase in number of cells producing acid sulphated glycoconjugates was accompanied with significant (α = 0.01) decrease in cells containing α(2-3) sialylated ones. In the ciliated cells, slight apical blebbing and mild signs of pathological alteration of the deeper portions of their cytoplasm were noticed. In the ciliary border, the mean number of cilia was 7.2 ± 0.3/m 2 . The altered kinocilia represented 5.8 ± 1.4%. These values were slightly but significantly (α = 0.01) lower compared with controls. As morphological signs of impaired self-cleaning ability of the airway epithelium, clumps of condensed mucus were discovered in the area of the slightly impaired ciliary border. According to our classification of the airway epithelium injury, the degree of damage to the tracheal epithelium was mild to moderate. Airways, ultrastructure, lectin histochemistry, glycoconjugates, ciliated cells, goblet cellsIn our preceding study, we demonstrated the effect of a single 10-min inhalation of mineral water on the airways. In the tracheal epithelium, the secretory elements were overstimulated and changes in the character of their glycoconjugates (GCs) were recorded . In clinical practice, whole series of inhalations are usually prescribed. Therefore, we decided to investigate also the effect of repeated inhalations of mineral water aerosol on the airway epithelium. Materials and MethodsIn our experiments, 13 SPF New Zealand White male rabbits (Charles River Deutschland, Sulzfeld, Germany) of body weight 1,500 -3,000 g, 3 -7 months of age were used. The animals were kept in our breeding facility under standard conditions, fed with complete granulated mixture TM-MaK 1. Seven animals served as untreated controls. For administration of mineral water aerosol, 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 µm, total output 0.6 g/min) was used. The rabbits inhaled an aerosol of natural hypertonic iodinated spring water (osmolarity 331 mOsm, pH 6.48) for 10 min 5× in the course of 5 days. Chemical composition of ...

Section: Discussionsupporting

confidence: 92%

Tracheal Epithelium of Rabbits after Repeated Inhalations of Mineral Water Aerosol

Vajner²,

Uhlı́k³

et al. 2001

Acta Vet. Brno

“…After mineral water inhalation, morphological signs of impaired self-cleaning ability of the airway epithelium were discovered (Konrádová 1990;Stratmann et al 1991;Wanner et al 1996;Geiser et al 1997). Layers of condensed mucus were found in the area of the slightly impaired ciliary border.…”

Section: Discussionmentioning

confidence: 99%

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

Vajner²,

Uhlı́k³

et al. 2003

Acta Vet. Brno

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, inhalationIn 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 MethodsIn 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 (K o n r á d o v á 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 % OsO 4 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 ...

“…Due to the combined exposure to hypoxia and increased humidity and temperature, morphological signs of impairment of the vital self-cleaning ability of the airway epithelium were recorded (Konrádová, 1991;Stratmann et al, 1991;Wanner et al, 1996;Geiser et al, 1997). Local disturbances in the mucus flow in airways were responsible for the appearance of small clumps of inspissated mucus in the area of the ciliary border.…”

Section: Discussionmentioning

confidence: 99%

Exposure to hypoxia injures tracheal epithelium (ultrastructural study)

Uhlı́k²,

Vajner³

et al. 2002

Vet. Med. - Czech

270Airway epithelium performing one of the vital self-cleaning functions plays important role in the development of many disorders of the respiratory organs. It represents the first barrier to the inhaled injurants, it reacts promptly on the changes in the environment or on the therapeutic and diagnostic procedures (Konrádová, 1991). To our knowledge, only a few authors dealt with the effect of hypoxia on the structure of the epithelium lining rabbits' respiratory organs. A decrease in number of cells that belong to the diffuse neuroendocrine system was described after short exposure to environment with 13% O 2 in the tracheal epithelium of young rabbits (Echt et al., 1982). In alveolar epithelium, degranulation of the type II pneumocytes was recorded after 16 hours spent in a chamber with 8% O 2 (Réffy et al., 1977). We therefore decided to investigate the reaction of the lining epithelium of airways under hypoxic conditions. e experiments were performed in a chamber containing atmosphere with 10% O 2 , where air humidity was 100% and temperature reached 23°C. To demonstrate the isolated effect of normobaric hypoxia, the control animals were exposed to atmosphere with only increased humidity and temperature. MATERIAL AND METHODSIn our experiments, 9 SPF New Zealand White male rabbits (Charles River Deutschland, Sulzfeld, Germany) of body weight 1 500-3 000 g were used. ree animals served as untreated controls. ree animals (treated controls) were placed for 96 hours in a normobaric chamber containing normal atmosphere with 100% humidity and temperature 23°C. ree rabbits spent 96 hours under the same conditions, but the atmosphere in the experimental Exposure to hypoxia injures tracheal epithelium (ultrastructural study) ABSTRACT: e ultrastructure of the tracheal epithelium in rabbits exposed for 96 hours to normobaric hypoxia was studied. In rabbits placed for 96 hours in environment with increased temperature and humidity, the first phase of common response of goblet cells to injury, represented mostly by degeneration of the exhausted cells, was revealed. e decrease in O 2 concentration highly accelerated the reaction of the goblet cells. Due to the influence of high temperature, humidity and normobaric hypoxia, the second phase of the goblet cells' reaction, massive differentiation of new secretory elements accompanied with intraepithelial mucous glands' development, was recorded. In the ciliated cells, only mild signs of pathological alteration of deeper portions of their cytoplasm were noticed. In the area of the ciliary border, significant decrease in the number of kinocilia/µm 2 , increase in percentage of altered cilia and morphological signs of impairment of the vital self-cleaning ability were recorded.