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Abstract

Background and Objective Vomeronasal organ VNO mediates the chemosensory communication. The VNO is well developed in the rabbit, however, the information about its embryonic development is lack. The current study aimed to summarize the developmental phases of the VNO development in the rabbits. Materials and Methods Pregnant rabbit does were euthanized and their fetuses were collected at 14, 17, 23, 25 and 30 days of gestation. The VNO were dissected from fetuses and processed for histological examination. Results On day 14 of gestation the olfactory placodes began as 2 epidermal thickenings, latero-ventral to the nasal septum. The 2 epithelia of the VNO lumen were a slit-like shape. On day 17, the VNO was kidney-shaped with a lateral concavity. It showed a thin lateral and thick medial wall. Blood sinuses and few nerve bundles appeared in lamina propria. On day 23, the outline of the VNO showed a crescent-shaped lumen. A few less-developed vomeronasal glands appeared in the lamina propria of the lateral and medial sides of the nasal cavity, where blood sinuses started to occupy larger spaces. On day 25, the VNO was partially enclosed by J-shaped hyaline cartilage and its lumen was oval in the coronal section. On day 30, the VNO grew reaching the adult size and its surrounding structures were enclosed in the J-shaped hyaline cartilage. Conclusion This study described the histological changes of VNO in rabbit embryos. That can be beneficial for understanding the physiology of the VNO in the rabbit and other species.