Scanning electron microscopy and histomorphology of the epiglottis in dromedaries: A study revealing unusual structure with the probable functional role.

While epiglottis is essentially a mammalian structure, studying its microstructure in any placental model will add an important information to the field of comparative anatomy and the related branches of biology. The aim of this study was to describe the structure of the epiglottis in dromedary camels using light and scanning electron microscopy (SEM), with reference to the possible functions. A total of 11 epiglottis cartilages from 11 larynges were used. The study revealed unusual, deeply situated glands just beneath the cartilage plate. They have unusually, wide surface-openings, while their ducts were partly located within the cartilage. This is presumed to be an adaptation to the need for rapid and efficient mucosal surface hydration in the arid conditions. The possible secretion transport mechanisms in these glands were also discussed. Furthermore, the SEM revealed for the first time, the presence of taste buds in camel epiglottis. However, in histological sections, visibility of taste buds was dependent upon the staining techniques. The taste buds were not seen with standard H& E stain, as they blended imperceptibly with the surrounding epithelium. Conversely, Mallory's trichrome showed contrasting colors, and taste buds were visible. In conclusion, camel epiglottis has an unusual structure, which may be correlated to environmental adaptation and important for the general health of upper respiratory tract in this species.

Expression of neuronal and non-neuronal markers in the vomeronasal organs of one-humped camel (Camelus dromedarius) and Egyptian water buffalo (Bubalus bubalis) / Expresión de marcadores neuronales y no neuronales en los órganos vomeronasales del camello jorobado y el búfalo egipcio de agua

Fourteen vomeronasal organs (VNOs) of adult males one-humped camels (Camelus dromedarius) and Egyptian water buffaloes (Bubalus bubalis) (n=7/each) were examined immunohistochemically with neuronal markers; synaptophysin (SYP) and glial fibrillary acidic protein (GFAP) to clarify the distribution of the vomeronasal (VN) receptor cells and nerve fibers, in addition to elucidate the existence of non-neuronal elements via S-100 and endothelial nitric oxide synthase (eNOS). In both animals, the VNO was lined medially with VN sensory (olfactory) epithelium and non-sensory (respiratory) epithelium laterally. Immunohistochemically, both animals showed SYP immunolabeling only in the receptor cells of VN sensory epithelium while GFAP labeled the ensheathing cells of the nerve fibers of VNOs. Both S-100 and eNOS labeled non-neuronal elements of the VNO; the supporting cells of sensory epithelium and the VN glands. In view of these observations, we postulate that the VNOs of both animals contain various cells populations that express several neuronal and non-neuronal markers. As well as, SYP and GFAP are suggested as markers for receptor cells and ensheathing cells of nerves of the VNOs respectively. However, no clear differences can be detected in the expressions of neuronal and non-neuronal markers in VNOs of camel and buffalo since they are ruminant species.

En este estudio fueron examinados 14 órganos vomeronasales (OVN) de machos adultos de camellos de una joroba (Camelus dromedarius) y búfalos egipcios de agua (Bubalus bubalis) (n = 7 / cada uno) por inmunohistoquímica con marcadores neuronales, sinaptofisina (SIP) y proteína ácida fibrilar glial (PAFG), para identificar la distribución vomeronasal (VN) del receptor de células y fibras nerviosas, además de dilucidar la existencia de elementos no neuronales a través de S-100 y óxido nítrico sintasa endotelial (ONSe). En ambos animales, el OVN se encuentra alineado en sentido medial con el epitelio sensorial (olfato) y lateralmente con el epitelio no sensorial (respiratorio). En el estudio inmunohistoquímico, ambos animales mostraron marcadores inmunológicos solamente en las células receptoras del epitelio sensorial VN, mientras que la proteína ácida fibrilar glial marcaba las fibras nerviosas de OVN. Tanto el S-100 como la óxido nítrico sintasa endotelial, marcaron elementos no neuronales del OVN, las células de revestimiento del epitelio sensorial y las glándulas VN. En relación a estas observaciones, se postula que los OVN de ambos animales contienen células que expresan varios marcadores neuronales y no neuronales. SIP y la PAFG se sugieren como marcadores para células receptoras y las células gliales de nervios del OVN, respectivamente. Sin embargo, debido a que son especies de rumiantes, no existen diferencias claras que se puedan detectar en las expresiones de los marcadores neuronales y no neuronales en el OVN de camello y búfalo.