Histomorphometrical and stereological study of the oesophagus in the adult male Persian squirrel (Sciurus anomalus)

Abstract

The Persian squirrel (Sciurus anomalus) is habitat in the Middle East countries and feed on pine acorns and other seeds. The present study was carried out to investigate the histological and volumetric features of the oesophagus in Persian squirrels. Five adult male Persian squirrels were included in the study. The cervical, thoracic and abdominal oesophagus of all subjects were processed routinely and sectioned in a serial manner. Then, the total volume of the oesophagus and its different layers were estimated using Cavalieri's principle. Histological assessment revealed a non‐keratinized stratified squamous epithelium lining the mucosa. No glands were seen in the lamina propria and submucosa. Lamina muscularis was present as a distinct layer of smooth muscle cells separating the lamina propria from the tunica submucosa. The tunica muscularis consisted of two distinct layers of striated muscle fibres: inner circular and outer longitudinal that was intermingled with few scattered smooth muscle fibres especially in the abdominal region. The thoracic region contained more amount of the lamina muscularis and tunica muscularis in comparison to the cervical or abdominal regions. The obtained results revealed that the histological structure of the Persian squirrel oesophagus has differences and similarities with other rodents and even with other species of squirrel. These findings would be useful to improve the knowledge in the areas of histological structure of the rodent digestive system.

Microscopic anatomy of the oesophagus in the southern white‐breasted hedgehog (Erinaceus concolor) a histochemical, stereological, and scanning electron microscope study

“…The oesophagus of the southern white‐breasted hedgehog had entirely a non‐keratinized stratified squamous epithelium. This observation is consistent with that reported in the rabbit (Selim et al, 2017), Persian squirrel (Goodarzi et al, 2019), and African giant rat (Nzalak et al, 2010), but is contrary to those observed in the guinea pig (Berghes et al, 2011). In comparison with other mammals, herbivorous mammals such as horses, cows, and camels had a keratinized oesophageal epithelium (Eurell & Frappier, 2006; Nabipour et al, 2001).…”

“…This finding is in agreement with observations in the dog and ruminants (Eurell & Frappier, 2006). Similar findings were also reported in rodent species such as guinea pigs (Berghes et al, 2011), African tree Squirrel (Igbokwe & Obinna, 2016), and Persian squirrel (Goodarzi et al, 2019). However, tunica muscularis can be composed of three muscular layers in the rabbit (Mohammadpour & Darvishzadeh, 2014) and guinea pig (Francis, 1974).…”

“…The different parts of tunica mucosa including epithelium, lamina propria, and muscularis mucosa can be varied structurally in different species (Goodarzi et al, 2019). The epithelium of the oesophagus is a stratified squamous type in all mammalian species.…”

“…In addition to the present knowledge in the authentic references, there are also several descriptions of the comparative histology and histophysiology of the oesophagus in mammalian and non‐mammalian species such as the Persian squirrel ( Sciurius anomalus ) (Goodarzi et al, 2019), African giant rat ( Cricetomys gambianus ) (Nzalak et al, 2010), camel ( Camelus dromedarius ) (Jamdar & Ema, 1982), guinea pig ( Cavia porcellus ) (Berghes et al, 2011), pufferfish ( Tetraodontidae ) (Fagundes et al, 2016), Gopher snake ( Pituophis catenifer ) (Khamas & Reeves, 2011), Rana perezi ( Pelophylax perezi ) (Gallego‐Huidobro & Pastor, 1996), House musk shrew ( Suncus murinus ) (Takeuchi & Yoshioka, 2004). Considering the physiological function of the oesophagus in moving the bolus toward the stomach, knowing its structural properties in a given species can help to a deep understanding of oesophageal physiology.…”

Histology of the stomach in the Caucasian squirrel, a scanning electron microscope and immunohistochemical study

“…Literature review shows that few studies performed on the anatomical or histological feature of the gastrointestinal tract including topography and gross anatomy of the abdominal gastrointestinal tract (Tootian et al, 2013) and histochemical properties of the small intestine (Sadeghinezhad et al, 2012). Recently, Goodarzi et al (2019) described the histological and stereological properties of the esophagus in this species.. However, the histological features of the stomach in this species remains unclear.…”