Steroidogenesis during prenatal testicular development in Spix's cavy Galea spixii

Morphohistometric and steroidogenic parameters during testicular and epididymal differentiation in cavy (Galea spixii) fetuses

Sexual differentiation and steroidogenic mechanisms have an important impact on postnatal gonadal phenotypic development. Thus, establishing the activities that lead to male phenotypic development can provide a better understanding of this process. This study examined the prenatal development of cavies to establish morphological and histometric development patterns and protein and enzyme immunolocalization processes that are responsible for androgen synthesis in the testes and epididymis. Histological and histometric analyses of the diameter of the seminiferous cords and epididymal ducts of male fetuses on Days 25, 30, 40, and 50 were performed, as well as immunohistochemistry of the steroidogenic enzymes 5α-reductase and 17β-HSD, the androgen receptor, and the anti-Müllerian hormone (AMH). Our findings showed a cellular grouping of gonocytes from Day 30 onward that was characteristic of the seminiferous cord, which was not present in the lumen at any of the studied dates. From Day 50 onward, the differentiation of the three anatomical regions of the epididymis was evident, the head (caput), body (corpus), and tail (cauda), with tissue distinctions. Furthermore, the diameters of the seminiferous cords and epididymal ducts significantly increased with age. On Day 50, the tail showed the greatest diameter of the three regions. The Sertoli and Leydig cells exhibited AMH immunoreactivity at all dates. In addition, the Leydig cells and epididymal epithelial tissue were immunopositive for 5α-reductase, 17β-HSD, and the androgen receptor; therefore, these factors influenced the development and maintenance of the testis and epididymis during cavy prenatal development.

Steroidogenic activity and morphological characterization of prenatal testes and epididymis of guinea pig (Cavia porcellus)

The present study aims to establish the morphological, morphometric, and immunostaining patterns of the steroidogenic enzymes 17β-HSD and 5α-reductase and androgen receptors (AR) during the prenatal development of the male gonad and epididymis of Cavia porcellus. Fetuses at 22, 25, 30, 40, 45, 50, and 60 days of gestation (DG) were used. Specimens were dissected and subjected to macroscopic, histological, histomorphometric, and immunohistochemical analyses. Genital and scrotal protrusions were identified in 22 DG embryos. Gonocytes were identified at 25 DG and the formation of primary testicular cords was observed at 30 DG. Through anatomical evaluation, we observed differentiation of the epididymis into the head, body, and tail at 45 DG. During development, there is a progressive decrease in the diameters of the testicular cords and epididymal ducts. 17β-HSD enzyme immunostaining was observed in Leydig cells at all ages, while 5α-reductase was observed in Leydig cell cytoplasm and gonocytes at 40, 50, and 60 DG. AR shows gonocyte labeling at 30 DG. Thus, from the second trimester of pregnancy, it is possible to observe patterns of anatomical development, such as genital and scrotal prominence (22 DG), the appearance of gonocytes in the testicular cords at 25 DG, and the beginning of the organization of primary testicular cords at 30 DG, suggesting sexual differentiation. The 17β-HSD, 5α-reductase, and ARs play an essential role in sexual development and differentiation, presenting immunostaining at different reproductive process times.

Prolonged use of letrozole causes morphological changes on gonads in Galea spixii

Letrozole is used as a therapeutic agent in reproductive disorders caused by high estrogen levels. Letrozole inhibits cytochrome P450 aromatase and reduces estrogen levels. However, the effects of long-term use on reproductive traits are unknown. The aim of this study was to evaluate the prolonged use of letrozole in the gonads of rodents (Spix's yellow-toothed cavy; Galea spixii). Forty-eight rodents (24 males and 24 females) were randomly divided into the treated and control groups. Letrozole administration started at 15 days of age and continued weekly until 30, 45, 90, and 120 days of age. The body, testis, and ovary weights were analyzed, as well as the morphological progression of spermatogenesis and folliculogenesis. Macroscopically, body weight gain and gonads weight were increased in the letrozole group. Microscopically, the ovaries of treated females showed stratified epithelium and a cellular disorder of the tunica albuginea. In the testes of treated males, the development of seminiferous tubules was delayed and sperm was absent. The collective findings indicate that the prolonged use of letrozole alters secondary sexual characteristics, and causes weight gain, reproductive changes, and male infertility.