The Effect of Intravenously Administered acetylcholine on the Glycoconjugate Composition on Goblet Cells of the Tracheal Epithelium in Rabbits

et al. 2001

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Vajner L., V. Konrádová, J. Uhlík, J. Zocová: Mucin Histochemistry of Tracheal Goblet Cells after Oral Administration of Ambroxol. Acta Vet. Brno 2001, 70: 9-13. Previous studies on the effect of various mucolytic drugs on the tracheal epithelium ultrastructure revealed ambroxol as the most harmful one. To complete these studies, we decided to evaluate the effect of ambroxol on the glycoconjugate content in the secretion of tracheal goblet cells.Using the methods of both conventional and lectin histochemistry, the percentage of tracheal goblet cells containing various glycoconjugates was evaluated. Twenty minutes after oral administration of 7.5 mg of ambroxol, goblet cells containing neutral glycoconjugates disappeared from the rabbit tracheal epithelium. Among goblet cells containing acidic glycoconjugates, the percentage of sialylated glycoconjugate-containing ones slightly decreased compared with control healthy rabbits.Oral administration of ambroxol only slightly affected the composition of glycoconjugates contained in goblet cells of the tracheal epithelium in rabbits. Tracheal goblet cells, conventional and lectin histochemistry, mucolytic drug ambroxol, rabbitAmbroxol, the most frequently used mucolytic agent in clinical practice, affects both ciliated and secretory cells in the respiratory system. It stimulates ciliary activity as well as incorporation of precursors into phospholipids in granular pneumocytes causing thus a decrement of mucus adhesion to the hypophase. According to pharmacological studies, it facilitates incorporation of hydrolytic enzymes into lysosomes of the airways' secretory cells. Activation of these acidic mucopolysaccharide-degrading enzymes leads to a decrease of the sputum viscosity (·míd and Holcát 1994). In our previous studies, reactions of the rabbit tracheal epithelium to oral administration of a single therapeutic dose of 6 various mucolytic drugs were compared. The adverse effect of ambroxol was the most pronounced (Konrádová et al. 1985ab;1996a). More than ninety seven per cent of the goblet cells had been stimulated to discharge their mucus. They either released their secretion from apical granules and/or detached packets of granules (14.5%) or were completely evacuated (83%) and only remnants of their degenerated cytoplasm were left in the epithelium. On the other hand, the cells of the rabbit terminal bronchiole revealed only mild signs of pathological alteration after oral administration of ambroxol and the secretory activity of Clara cells did not differ from that found in controls (Uhlík et al. in press). Lamb and Reid (1972) and Damyanov (1987) deduced a common tendency to the decrease of sialylated glycoconjugates and the increase of sulphated ones as the reaction to any alteration of the tracheal epithelium.To complete the study, changes of the glycoconjugate content of the tracheal goblet cells were studied under the same experimental conditions using both conventional and lectin histochemistry.

Section: Discussionsupporting

confidence: 90%

Mucin Histochemistry of Tracheal Goblet Cells after Oral Administration of Ambroxol

Vajner¹,

Konrádová²,

et al. 2001

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“…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 (Boehringer, Mannheim, Germany), and Tritrichomonas mobilensis lectin TML (Calbiochem, La Jolla, USA) were used.…”

Section: Methodsmentioning

confidence: 99%

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

Konrádová¹,

Vajner²,

et al. 2003

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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 ...

“…The α(2-6) sialylated GCs disappeared completely from the epithelium. In our previous studies, we demonstrated that the disappearance of the α(2-6) sialylated GCs was one of the first signs of goblet cells overstimulation (Vajner 1998;Konrádová et al 2000;Vajner et al 2000). After administration of some bronchospasmolytic drugs, high level of goblet cells injury resulted in absolute predominance of acid sulphated GCs (Konrádová et al 1997(Konrádová et al , 1998Vajner 1998).…”

Section: Discussionmentioning

confidence: 96%

Changes in the Tracheal Epithelium During 24 h After Inhalation of Mineral Water

Konrádová¹,

Vajner²,

et al. 2001

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Inhalation of aerosol of mineral water is frequently used in therapy of various respiratory disorders. Ultrastructure of the airway epithelium in rabbits and character of glycoconjugates produced by secretory cells were studied immediately and 24 h after 10-min inhalation of this aerosol. Goblet cells were overstimulated and the mechanism of mucus evacuation was accelerated. The exhausted goblet cells mostly took part in further secretory cycles, but the number of degenerated secretory elements gradually increased in the course of 24 h. Cells not entirely filled with secretory granules prevailed in the epithelium. Massive differentiation of goblet cells and development of intraepithelial mucous glands were noticed. Compared with controls, significant (α = 0.01) decrease in the acid sulphated glycoconjugates in the secretion of the goblet cells was accompanied by an increase of the acid sialylated ones immediately after inhalation. Twenty-four hours post exposure, significant (α = 0.05) decrease in total sialylated glycoconjugates was ascertained. The ciliated cells revealed only mild pathological alteration. Significant (α = 0.01) decrease in number of kinocilia/µm 2 was accompanied by an increase in percentage of altered cilia. During 24 h post exposure, signs of ciliary border regeneration were noticed. Morphological signs of impaired self-cleaning ability of the airway epithelium were encountered during the whole experiment. Single 10-min inhalation of mineral water aerosol caused changes in the ultrastructure of the airway epithelium and influenced the chemical composition of the goblet cells' secretion. These changes did not disappear completely during 24 h post exposure. Airways, ultrastructure, regeneration, lectin histochemistry, glycoconjugates, rabbitIn our previous study, we demonstrated that 10-min inhalation of saline affected the ultrastructure of the airway epithelium (Konrádová et al. in press). We therefore decided to study also the effect of aerosol of mineral water, frequently used in therapy of various respiratory disorders, and to follow the process of regeneration of this epithelium in the course of 24 h. 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 µm, total output 0.6 g/min). The rabbits inhaled an aerosol of mineral water for 10 min. Chemical composition of this spring water is given in Tab. 1. Under general anaesthesia, the material for electron microscopic and histochemical examinations was collected from six animals immediately and 24 h post exposure, respectively.Tiny fragments of the tracheal mucous membrane were processed using standard methods for electron microscopy (Konrádová 1991). The ciliary border and ...