Histology and scanning electron microscopy of the lower respiratory tract in the adult red fox (Vulpes vulpes) / Histología y microscopía electrónica de barrido de las vías respiratorias inferiores en el zorro rojo adulto (Vulpes vulpes)

The study was conducted on a total of three adult healthy freshly killed red foxes of both sexes weighing about 4-6 kg collected from Abou Rawwash, Giza, Egypt. The wall of trachea and bronchi formed of mucosa, submucosa and adventitia. The mucosa formed of pseudostratified columnar epithelium and lamina propria. The respiratory epithelium composed of tall columnar ciliated, goblet cells, basal cells, and neuroendocrine cells. Goblet cells account for about 20 to 30% of cells in the more proximal. Basal cells are relatively small triangular cells whose bases are attached to the basement membrane. The primary bronchiole is lined by simple columnar nonciliated to cuboidal epithelium containing some bronchiolar exocrine cells and some goblet cells. Neuroendocrine cells constitute about 4 to 5% of bronchial epithelial cells, attached at their bases to the basement membrane and have tapering apices. The lamina propria consists principally of a network of capillaries, a meshwork of connective tissue fibers continuous with the basement membrane. The submucosa formed of connective tissue elements and blood vessels and devoid of Tracheobronchial glands in red fox. The adventitia contain tracheal cartilage and muscle in trachea and bronchial cartilages and muscles in bronchi. Tracheal muscle is transverse bundles attached to the outer perichondrium. In the bronchi, muscle is organized in transverse bundles close to the epithelium adjacent to the lamina propria and longitudinal bundles close to the cartilages. Alveoli are demarcated by septa composed of a continuous layer of epithelial cells overlying a thin interstitium. The epithelial cells consist principally of type I and type II pneumocytes. SEM revealed that, the mucosal surface of both trachea and bronchi was completely covered by cilia. There were few glandular openings or goblet cell.

El estudio se realizó en tres zorros rojos adultos sanos, recién fallecidos, de ambos sexos, con un peso aproximado 4,6 kg recogidos de Abou Rawwash, Giza, Egipto. La pared de la tráquea y los bronquios estaban formados por mucosa, submucosa y adventicia. La mucosa estaba formada por un epitelio estratificado y lámina propia. El epitelio respiratorio ciliado compuesto de células caliciformes, células basales y células neuroendocrinas. Las células calciformes representaban alrededor del 20 al 30% de las células más proximales. Las células basales eran células triangulares relativamente pequeñas cuyas bases están unidas a la membrana basal. El bronquiolo principal está cubierto por un epitelio columnar simple no ciliado que contiene algunas células exocrinas bronquiolares y células caliciformes. Las células neuroendocrinas constituyen aproximadamente 4 a 5% de las células epiteliales bronquiales, unidas en sus bases a la membrana basal y tienen ápices de ahusamiento. La lámina propia consiste principalmente en una red de capilares, una malla de fibras de tejido conectivo continuo con la membrana basal. La submucosa formada por elementos del tejido conectivo y vasos sanguíneos y escasas glándulas traqueobronquiales. La capa adventicia contiene cartílago traqueal y muscular en la tráquea, y los bronquios cartílagos y músculos. En los bronquios, el músculo está compuesto de haces transversales cercanos al epitelio próximo a la lámina propia y haces longitudinales cerca de los cartílagos. Los alvéolos están delimitados por tabiques compuestos de una capa continua de células epiteliales que recubren un intersticio delgado. Las células epiteliales se componen principalmente de neumocitos tipo I y tipo II. El MEB reveló que la superficie de la mucosa de la tráquea y los bronquios estaba completamente cubierta por cilios. Se observaron pocas aberturas glandulares o células caliciformes.

Light-emitting diode effects on combined decellularization of tracheae. A novel approach to obtain biological scaffolds

PURPOSE: To obtain a decellularized tracheal scaffold associating traditional approaches with the novel light-emitting diode (LED) proposal. METHODS: This study was performed with New Zealand adult rabbits weighing 3.0 - 4.0 kg. Different protocols (22) were used combining physical (agitation and LED irradiation), chemical (SDS and Triton X-100 detergents), and enzymatic methods (DNase and RNase). RESULTS: Generally, the cells surrounding soft tissues were successfully removed, but none protocol removed cells from the tracheal cartilage. However, longer protocols were more effective. The cost-benefits relation of the enzymatic processes was not favorable. It was possible to find out that the cartilaginous tissue submitted to the irradiation with LED 630nm and 475 nm showed an increased number of gaps without cells, but several cells were observed to be still present. CONCLUSION: The light-emitting diode is a promising tool for decellularization of soft tissues. .

The impact of topically applied preservation solutions on the respiratory epithelium of tracheal grafts submitted to cold ischemia: functional and morphological analysis

OBJECTIVE: Advances in graft reepithelialization and revascularization have renewed interest in airway transplantation. This study aims to determine whether topically applied preservation solutions can ameliorate ischemic injury to tracheal grafts. We analyzed 1) the effects of cold ischemia on the mucociliary clearance of tracheal grafts and 2) the impact of topically applied preservation solutions on the effects of cold ischemia on mucociliary clearance. METHOD: Tracheal segments (n=217) from 109 male Wistar rats were harvested, submerged in low-potassium-dextran-glucose, histidine-tryptophan-ketoglutarate, or saline solution (saline group), and stored at 4°C for 6, 10, 16, or 24 hours. A control group (not submerged) was analyzed immediately after harvesting. In situ mucociliary transport and ciliary beating frequency were measured using a stroboscope. Epithelial integrity, cellular infiltration, and mucus storage were quantified by light microscopy and image analysis software, along with transmission electron microscopy. RESULTS: 1) The effects of cold ischemia: in situ mucociliary transport and ciliary beating frequency were greater in the control group than after cold ischemia. Microscopic analysis results were similar between groups. 2) The effects of preservation solutions: there was no difference between the low-potassium-dextran-glucose, histidine-tryptophan-ketoglutarate, and saline groups in functional or light microscopy analysis. The saline group presented stronger signs of ischemic injury with transmission electron microscopy. CONCLUSIONS: Cold ischemia diminished the mucociliary clearance of the tracheal respiratory epithelium. Topically applied preservation solutions did not ameliorate the injury caused by cold ischemia to the tracheal respiratory epithelium. .

Structure and concentration of elastic system fibers in the trachea of the rat / Estructura y concentración del sistema de fibras elásticas en la tráquea de la rata

The extracellular matrix is a key element in the tracheal morphology and physiology, both in normal and pathological states, yet little is known regarding its composition and organization. Herein we carried out a detailed study of the morphological organization and volumetric density of elastic system fibers in the trachea of Wistar rats. Six Wistar rats at the age of 45 days were used. The trachea was excised following anesthesia with Thiopental and perfusion through the left ventricle with buffered saline followed by formalin solution. Samples were fixed in formaline, embedded in paraffin, and histologically processed. The elastic system fibers were evaluated at light microscopy by using Weigert's resorcin-fuchsin technique after oxidation with oxone. Morphometric studies were performed by the point-counting method. Quantities were expressed ( percent, mean) as volumetric densities and were determined on 25 random fields for each animal. Elastic system fibers were identified beneath the tracheal mucosa showing mainly a longitudinal profile. There were also some bundles of oblique fibers in this region, forming an irregular network of elastic tissue. Close to the inner surface of the cartilaginous ring, a well defined circular layer is present. The volumetric density of the elastic system fibers in the trachea of Wistar rats is 2.46 +/- 0.99 percent. The data in the present study provides original information regarding the elastic system fibers of the rat trachea, which might be used as a model for studying human major airway morphology. The results reported herein provide the basis for continuous investigations on tracheal extracellular matrix by stereology.

La matriz extracelular es un elemento clave en la morfología y fisiología de la tráquea, tanto en estados normales como patológicos. Sin embargo, poco se sabe acerca de su composición y organización. Se llevó a cabo un estudio detallado de la organización morfológica y la densidad volumétrica de fibras del sistema elástico en la tráquea de ratas Wistar. Se utilizaron seis ratas Wistar edad de 45 días de vida. La tráquea fue extraída después de anestesia con tiopental y la perfusión a través del ventrículo izquierdo con solución salina tamponada seguido de solución de formalina. Las muestras fueron fijadas en formalina e incluidas en parafina y se procesaron histológicamente. Las fibras del sistema elástico fueron evaluadas en microscopía de luz utilizando la técnica de Weigert, resorcina-fucsina después de la oxidación con Oxone. Los estudios morfométricos fueron realizados por el método de conteo de puntos. Las cantidades se expresaron ( por ciento, media) como la densidad volumétrica y se determinaron en 25 campos al azar para cada animal. Las fibras elásticas del sistema fueron identificadas por bajo la mucosa traqueal que muestra principalmente un perfil longitudinal. También se encontraron algunos haces de fibras oblicuas en esta región, formando una red irregular de tejido elástico. Cerca de la superficie interna del anillo cartilaginoso, una capa bien definida circular está presente. La densidad volumétrica de las fibras del sistema elástico en la tráquea de ratas Wistar fue de 2,46 +/- 0,99 por ciento. Los datos del presente estudio proporcionan información inicial sobre las fibras del sistema elástico de la tráquea de rata, que puede ser utilizado como un modelo para el estudio de la morfología de las vías respiratorias humanas. Los resultados reportados en este documento constituyen la base de investigaciones continuas en la tráquea de la matriz extracelular por estereología.

Cryptosporidium sp. em intestinos, bursa de Fabricius e traquéia de frangos (Gallus gallus sp) / Cryptosporidium sp. in intestines, bursa of Fabricius and poultry trachea (Gallus gallus sp)

Parasitas do gênero Cryptosporidium infectam várias espécies de animais, e a enfermidade resultante é a criptosporidiose, importante zoonose de distribuição mundial. Em aves, a infecção tem sido reportada em várias espécies. Este trabalho objetivou identificar a presença do parasita em 208 amostras de bursa de Fabricius, 208 amostras de intestino e 208 de traquéia, coletadas de frangos (Gallus gallus sp) de diferentes idades, abatidos em três propriedades rurais do município de Santa Maria, RS. Foram feitas três impressões de cada amostra em lâminas para microscopia, coradas pelas técnicas de Ziehl Neelsen modificada com Dimetil Sulfóxido (DMSO), Ziehl Neelsen modificada por Henriksen e Pohlens (HP), Ziehl Neelsen (ZN) e Kinyoun (K), perfazendo 1872 impressões analisadas em microscopia óptica (1000 x). Neste total, nas diferentes colorações empregadas, oocistos do parasita Cryptosporidium sp. foram visualizados em 18 impressões de traquéia, 42 de bursa de Fabricius e 29 de intestino, resultando positivas, portanto, 89 impressões. Destas, 44 foram identificadas pela técnica de DMSO, 32 por HP, três por ZN e 10 por K. Pode-se concluir que os oocistos do parasita Cryptosporidium sp. foram visualizados com maior freqüência nas impressões de bursa de Fabricius, e que o método de coloração, dentre os utilizados, que proporcionou a maior visualização dos oocistos foi o DMSO.

Ultaestructura del epitelio traqueal en recién nacidos pretérmino sometidos a ventilación mecánica / Ultraestructure of tracheal epithelium in preterm newborns under mechanical ventilation

Se evaluó el daño del epitelio traqueal en prematuros qeu estuvieron intubados y sometidos a ventilación mecánica. Se realizaron biopsias a siete neonatos pretérmino, el peso varió de 1100 a 2350 g, 5 nacieron por cesárea y dos por vía vagonal. El cultivo bronquial fue negativo en 5, en uno se aisló Lysteria monocitogena y en otro Pseudomonas sp. La biopsia se tomó a diferentes tiempos de intubación, un caso de un día, tres casos a los tres días, 1 caso a los 14 días, un caso a los 17 día y un caso a los 17 días postextubación. El tejido obtenido se procesó de acuerdo a las técnicas habituales de microscopía electrónica. Se examinaron cortes semifinos y finos; éstos últimos observados en un microscopio electrónico de transmisión Zeiss. Cinco fallecieron por neumonía asociada con otras patologías. En el estudio óptico y ultraestructural se encontró que con un día de intubación sólo había pérdida de cilios, con tres días de ventilación se observó pérdida de células ciliadas y no ciliadas, muerte celular y ausencia de uniones celulares. En un caso con tres días de ventilación y 17 días de posextubación que cursó con infección por pseudomonas se encontraron zonas ulceradas y edema. A los 14 días se encontraron zonas de necrosis, incremento en la colágena. A los 17 días de observaron varias zonas ulceradas hasta la capa muscular con formación de fibrosis y restos celulares en la luz traqueal. Se concluye que la ventilación mecánica y la presencia de una sonda, dañan el epitelio bronquial desde las primeras 24 horas

Ultrastructure of the tracheobronchial epithelium of the normal and formaldehyde-exposed guinea-pig

Thirty adult male guineca pigs were used in this study, fifteen taken as control, while the other fifteen were exposed to formaldehyde.The tracheobronchial epithelium of all animals were examined by means of light and electron microscopy. The tracheobronchial epithelium of the control animals was found to consist of ciliated, goblet, basal and intermediate cells. The general structure of the epithelium is suggested to provide a barrier restricting the transfer of exogenous material from the airway lumen to the blood stream. Moreover, the actively motile cilia of the ciliated cells are responsible for transport of mucus with included foreign materials to the throat where the mucus normally swallowed. The goblet cells continuously secrete mucus which formed a physical barrier between the inhaled pollutants and underlying epithelium. The results of this work suggest that, both motile cilia and secretion of correct amount of mucus with suitable vesicoelasticity are responsible for maintenance of mucociliaryy clearance. Also the intermediate cells were observed to be differentiated into goblet cells. Following formaldehyde exposure, profound general and special epithelial and submucosal changes, ranging from moderate to severe were observed within the tracheobronchial epithelium.Early after short periods of formaldehyde exposure, the structural changes in the bronchial epithelium were observed to be less severe than that of the tracheal epithelium. However, later on, with prolongation of the period of formaldehyde exposure, both trachea and bronchi were severely affected. The general epithelial changes included, 1] ulceration of the tracheobronchial epithelium which is emphasized to expose and sensitize the airway receptors to inhaled irritants which are responsible for the pathogenesis of occupational asthma. 2] proliferative changes in the form of simple hyperplasia, basal and goblet cell hyperplasia and squamous metaplasia have occurred and suggested the possibility of formaldehyde carcinogenicity 3] thickening of the basement membrane which is considered to be a protective mechanism against inhaled formaldehyde. On the other hand, the special epithelial changes were evidenced by the appearance of a great number of ciliary abnormalities and apocrine, massive mucus secretion of the goblet cells with subsequent impairment of the mucociliary clearance. Both fibrosis and airway obstruction are considered to be the latest sequlae of long term injury produced by formaldehyde exposure as indicated by the appearance of fibroblasts and smooth muscle fibers within the submucosa of tracheobronchial epithelium

Ultrastructure of the tracheobronchial epithelium of the normal and formaldehyde-exposed guinea-pig

Thirty adult male guinea pigs were used in this study, fifteen were taken as control, while the other fifteen were exposed to formaldehyde.The tracheobronchial epithelium of all animals were examined by means of light and electron microscopy. The tracheobronchial epithelium of the control animals was found to consist of ciliated, goblet, basal and intermediate cells. The general structure of the epithelium is suggested to provide a barrier restricting the transfer of exogenous material from the airway lumen to the blood stream. Moreover, the actively motile cilia of the ciliated cells are responsible for transport of mucus with included foreign materials to the throat where the mucus normally swallowed. The goblet cells continuously secrete mucus which formed a physical barrier between the inhaled pollutants and underlying epithelium. The results of this work suggested that, both motile cilia and secretion of correct amount of mucus with suitable vesicoelasticity are responsible for maintenance of mucociliary clearance. Also the intermediate cells were observed to be differentiated into goblet cells. Following formaldehyde exposure, profound general and special epithelial and submucosal changes, ranging from moderate to severe were observed within the tracheobronchial epithelium. Early after short periods of formaldehyde exposure, the structural changes in the bronchial epithelium were observed to be less severe than that of the tracheal epithelium. However, later on, with prolongation of the period of formaldehyde exposure, both trachea and bronchi were severely affected. The general epithelial changes included, 1] ulceration of the tracheobronchial epithelium which is emphasized to expose and sensitize the airway receptors to inhaled irritants which are responsible for the pathogenesis of occupational asthma. 2] proliferative changes in the form of simple hyperplasia, basal and goblet cell hyperplasia and squamous metaplasia have occurred and suggested the possibility of formaldehyde carcinogenicity 3] thickening of the basement membrane which is considered to be a protective mechanism against inhaled formaldehyde. On the other hand, the special epithelial changes were evidenced by the appearance of a great number of ciliary abnormalities and apocrine massive mucus secretion of the goblet cells with subsequent impairment of the mucociliary clearance. Both fibrosis and airway obstruction are considered to be the latest sequlae of long term injury produced by formaldehyde exposure as indicated by the appearance of fibroblasts and smooth muscle fibers within the submucosa of tracheobronchial epithelium