Gonadal Differentiation During Embryonic and Fetal Development of Male New Zealand Rabbits (Oryctolagus cuniculus)

• Published in: International journal of morphology Vol. 39; no. 5; pp. 1253 - 1263
• Main Authors: Miranda, Carla Maria Figueiredo de Carvalho, Leonel, Luciano César Pereira Campos, Koga, Bruna Andrade Aguiar, Anunciação, Adriana Raquel de Almeida da, Mario, Lara Carolina, Favaron, Phelipe Oliveira, Martins, Daniele dos Santos, Vásquez, Bélgica, Conei, Daniel, Miglino, Maria Angélica, del Sol, Mariano
• Format: Journal Article
• Language: English; Spanish; Portuguese
• Published: Universidad de La Frontera, Facultad de Medicina 01.10.2021; Sociedad Chilena de Anatomía
• Subjects: ANATOMY & MORPHOLOGY; Desert hedgehog; Células germinales primordiales; Embryonic development; Túbulos seminíferos; Sustentacular cells; Células sustentaculares; Gónadas; Desarrollo embrionario; Seminiferous tubules; Primor- dial germ cells; Gonads
• ISSN: 0717-9502; 0717-9367; 0717-9502
• DOI: 10.4067/S0717-95022021000501253

The rabbit is considered an ideal animal model for studies that describe abnormalities in the testicles due to the similar morphogenetic mechanisms of sexual development and diseases commonly found in humans. The aim of this study was to determine the male sexual differentiation of the New Zealand rabbit (Oryctolagus cuniculus) through development. The gestational age was estimated and classified as 9, 12, 14, 16, 18, 20, 23 and 28 gestational days. The morphological and sexual determination were performed by histological analysis of the reproductive tract in the embryos and fetuses (9-28 days) as well as by immunohistochemistry-Desert hedgehog-Dhh- (testis-specific protein on Y chromosome- 16, 20, 23 days and adult rabbits). Gonads were observed from the 14th day in an undifferentiated stage and with homogeneous aspect. Sexual differentiation was observed from the 16th day with presence of cells forming gonadal cords and Dhh (+) cells in the gonadal parenchyma. From the 18th gestational day testicular cords were observed, which evolved into organized seminiferous tubules. The formation of the efferent ducts and ductus deferens and epididymis was observed on the 20th and 23rd days, respectively. The differentiation of the external genitalia occurred from the 23rd days from the anogenital distance and was identified to identify the penile structures. In summary, the features of the sexual differentiation were determined by observation of the Dhh (+) protein in embryos from the 16th day to adulthood, and the morphological particularities observed from the 18th gestational day, determined by differentiation of the external genitalia from the 23rd day. KEY WORDS: Gonads; Embryonic development; Seminiferous tubules; Desert hedgehog; Sustentacular cells; Primordial germ cells.