Prenatal Development of the Vomeronasal Organ in Rabbit

Abstract

The vomeronasal organ (VNO) is the peripheral receptors, with the ability to detect pheromones, and so it has a role in social behavior, sexual reactions and reproduction. The aim of this study was to designing, categorize, define and demonstrate the normal explaining of the onset time of first appearance and origin as well as developmental changes of vomeronasal organ of the rabbit and its allied structures. This study was carried out on 116 rabbit embryos and fetuses of both sexes. The specimens were obtained, from 14 normal and apparently healthy adult female rabbits. At days (D) 9-11 of pregnancy the nasal placode was invaginated to form the nasal (olfactory) pits. The primordia of the VNO was formed at the ventromedial area of this nasal pit. At D13, the VNO appeared as bilateral un-differentiated epithelial thickenings of the rostroventral part of nasal septum. At D14, the dorsomedial part of the epithelium was about a twice as thick as its ventrolateral part. At D16the VNO opened into the nasal cavity the miniature VNO nerve fascicles were appeared. At D18, VNO immature glands appeared in the dorsolateral part of the VNO the chondral plate was differentiated into chondroblasts. The lumen of the VNO was extremely increased in wide and closed to be oval lumen. At D20, the rostral opening of VNO duct opened directly into the floor of nasal cavity. The medial wall was thicker and had about 8-10 layers of stratified columnar and the lateral one consisted of 3-4 pseudostratified columnar cell layer. At D22, the of acini of the VNO glands determined at the dorsal commissure of the VNO duct. At D28, the lumen was lined by a thick medial mucosa with stratified olfactory like epithelium and thin ventrolateral respiratory epithelium.

Comparative morpho-histological analysis on the vomeronasal organ and the accessory olfactory bulb in Balady dogs (Canis familiaris) and New Zealand rabbits (Oryctolagus cuniculus)

“…Our work revealed that the VD of dogs and rabbits had medial sensory and lateral respiratory epithelium. Similar results were reported in dogs [13,14], rabbits [16,37], cats [44], sheep [41], and pigs [10]. Also, we found areas of stratified squamous near the dorsal end of the duct in rabbits and the caudal part of the organ of the dog had only the SE.…”

“…However, sheep and goats had a bodyweight resembling that of dogs, but the length of the organ was 6–8 cm in goat [30], 6–9 cm in Iraqi sheep [31], and 10.6 mm in African giant rat [35]. The vomeronasal organ of rodents [16] and rabbit [36,37] opened in the nasal cavity and indirectly connecting with the oral cavity by the nasopalatine duct, whereas in carnivores [13,34], goat [30], and bears [38], the organ united with the nasopalatine duct and had a direct connection with the oral cavity.…”

Prenatal Development of the Nasal Conchae (Conchae nasales) in Rabbits (Oryctolagus cuniculus)

“…The heads of the fetuses over 20 days were immersed in EDTA 5.5% buffered to 7.0 PH with sodium hydroxid and neutralized in 5% sodium sulphate. The time taken for decalcification depended on the age of fetuses according to Drury and Wallington (1980), Alomaisi et al, (2018), Alomaisi et al, (2019).…”