Histochemical and Ultrastructural Observations of Respiratory Epithelium and Gland in Yak (Bos grunniens)

Abstract

Submucous glands and epithelial mucous cells of yak (Bos grunniens) respiratory tract have been studied by a variety of histochemical methods and transmission electron microscopy for differentiating and characterizing serous and mucous cells. By light microscopy, the distribution, numbers of mucous cells, volume of mucous glands (Reid index), and the ratio of mucous cell to serous cell in the bronchial tree were measured with different staining. Histochemically, a majority of mucous cells, presented in the surface epithelium of bronchi and glands, secreted neutral and acid mucosubstances, only a few sulfated mucosubstances were present. No mucus-producing cells were observed from the terminal to respiratory bronchiolar level. Ultrastructurally, serous cells in glands of the lamina propria had two distinct forms: one type filled with many round dense secretory granules, plentiful RER and few other organelles, similar to other animals; the other type contained some oval mitochondrial and distended RER, the granules resembled the former. The mucous cells in gland were similar to that of epithelium, which containing abundant secretory granules with an eccentric core. The mucous cells of the surface epithelium differ from other animals in the structure and histochemistry of their secretory granules. Analysis of the size and distribution of the secretory granules and other organelles of serous cells suggested that differences represent different phases of a secretory cycle, not various populations of cell or granules. Anat Rec, 293:1259Rec, 293: -1269

Development and characterization of an immortalized nasopharyngeal epithelial cell line to explore airway physiology and pathology in yak (Bos grunniens)

“…The yak, a species uniquely adapted to high-altitude environments, exhibits distinct morphological and physiological characteristics compared to normal cattle ( 5 , 24 , 25 ). Recently, the molecular mechanisms under the functions of yak alveolar cells have garnered increasing attention ( 8 , 9 ).…”

“…Adapted to the plateau’s unique and harsh conditions, characterized by such as hypoxia, coldness, and long-term pasture shortage ( 1–3 ), yaks exhibit distinctive physiological traits. Notably, compared to the plains-dwelling yellow cattle, yaks possess a respiratory system with higher density of mucosal goblet cells, submucous glands, and tracheal cartilage ( 4 , 5 ). Our previous study also identified significant differences in the nasopharyngeal microflora between yaks and typical cattle ( 6 ).…”

Segmentation features and structural organization of the intrapulmonary artery of the yak

“…Sasaki reported the complete intrapulmonary artery segmentation of rat for the first time (Sasaki et al, ). For the yak lung, previous studies focused on pulmonary microvasculature (Du et al, ), respiratory epithelium and gland, morphological analysis of neonatal yak lung (Yang et al, ), and distribution of vascular endothelial growth factor in plateau yak lung (He et al, ). This study is the first to report the divisions of intrapulmonary artery tree, intrapulmonary artery segmentation and structural organization in the yak.…”

“…As a special plateau animal, many scholars have studied the yak in plateaus, focusing on reproductive organ anatomical features and ovarian morphology (Cui et al, 1999a,b; Yong et al, ), the pineal gland and thyroid structure (Wang et al, ), cranial neck ganglia and its branch (Shao et al, 2007, ), ventricular microvascular morphology (Cui et al, 2008; He et al, ), pulmonary microvasculature (Du et al, ), the sinus node and its artery (Duan et al, ), and placentome morphometric analysis (Liu et al, ). Studies on the plateau adaptive mechanism of the yak are available in the literature, including histochemical and ultrastructural observations of the respiratory epithelium and gland in Bos grunniens (Yang et al, ), morphological studies on the lung of yak (Yang et al, ), local anatomy of yak lung (Heath et al, ), structural characteristics and plateau adaptability of yak lung (Chen et al, ), and distribution of vascular endothelial growth factor in plateau yak lung (He et al, ). The intrapulmonary artery segment characteristics and the correlation between its structure and function have been recently reported.…”