Postnatal Sertoli and Leydig cell proliferation and the establishment of puberty and sexual maturity in Chinchilla lanigera (Rodentia, Chinchillidae)

摘要

The Chilean chinchilla (Chinchilla lanigera) is threatened in its natural habitat and there is very little informationnconcerning the reproductive biology of this species. Our main objectives were to investigate the postnatal testisndevelopment in this rodent, with emphasis on Sertoli and Leydig cell proliferation and the establishment of puberty andnsexual maturity. Forty-four animals from one day to 30 months of age had their testis and epididymis prepared (timenof collection for animals from 5 to 30 months of age, May–November in the southern hemisphere) for histological andnstereological analyses. Both Sertoli and Leydig cell proliferation occurred up to two months after birth and their totalnnumber per testis were stable thereafter. Based on spermatid release from the seminiferous epithelium and the presencenof sperm in the epididymis, puberty in chinchilla took place at around three months of age. However, testis weight andntubular diameter and epithelium height appeared to stabilise only after the animals reached 17 months of age, indicatingnthat the establishment of full sexual maturity in this species takes a relatively long period of time. This particular findingnindicates that chinchilla might represent an interesting experimental model to investigate the mechanisms that regulatenthe establishment of this important event of reproductive physiology in mammals.