Cortisol Directly Stimulates Spermatogonial Differentiation, Meiosis, and Spermiogenesis in Zebrafish (Danio rerio) Testicular Explants

Abstract

Cortisol is the major endocrine factor mediating the inhibitory effects of stress on vertebrate reproduction. It is well known that cortisol affects reproduction by interacting with the hypothalamic–pituitary–gonads axis, leading to downstream inhibitory and stimulatory effects on gonads. However, the mechanisms are not fully understood. In this study, we provide novel data demonstrating the stimulatory effects of cortisol on spermatogenesis using an ex vivo organ culture system. The results revealed that cortisol treatment did not modulate basal androgen production, but it influenced transcript levels of a selected number of genes involved in the zebrafish testicular function ar (androgen receptor), star (steroidogenic acute regulatory), cyp17a1 (17α-hydroxylase/17,20 lyase/17,20 desmolase), cyp11a2 (cytochrome P450, family 11, subfamily A, polypeptide 2), hsd11b2 (11-beta hydroxysteroid dehydrogenase), cyp2k22 (cytochrome P450, family 2, subfamily K, polypeptide 22), fkbp5 (FKBP prolyl isomerase 5), grα (glucocorticoid receptor alpha), and grβ (glucocorticoid receptor beta) in a short-term culture. We also showed that cortisol stimulates spermatogonial proliferation and differentiation in an androgen independent manner as well as promoting meiosis and spermiogenesis by increasing the number of spermatozoa in the testes. Moreover, we demonstrated that concomitant treatment with RU 486, a potent glucocorticoid receptor (Gr) antagonist, did not affect the cortisol effects on spermatogonial differentiation but blocked the induced effects on meiosis and spermiogenesis. Supporting the Gr-mediated effects, RU 486 nullified the cortisol-induced expression of sycp3l (synaptonemal complex protein 3), a marker for the meiotic prophase that encodes a component of the synaptonemal complex. This is consistent with in silico analysis that found 10 putative GREs (glucocorticoid response elements) upstream of the zebrafish sycp3l. Finally, we also showed that grα mRNA is expressed in Sertoli and Leydig cells, but also in several types of germ cells, including spermatogonia and spermatocytes. Altogether, this evidence indicates that cortisol exerts paracrine roles in the zebrafish testicular function and spermatogenesis, highlighting its effects on spermatogonial differentiation, meiosis, and spermiogenesis.

Transcriptomes of testis and pituitary from male Nile tilapia (O. niloticus L.) in the context of social status

“…In social cichlids, elevated cortisol levels can be associated with subordinate rank [ 216 ] or with periods of social change [ 14 , 217 , 218 ]. Although recent findings in zebrafish suggest that cortisol can also act as a promoter of spermatogenesis [ 219 ], elevated cortisol levels in fish are generally agreed to inhibit reproduction (for review see Rousseau et al . [ 220 ]).…”

Interaction of thyroid hormones and gonadotropin inhibitory hormone in the multifactorial control of zebrafish (Danio rerio) spermatogenesis

“…Reproduction is under multifactorial control of neurohormones, pituitary hormones, glucocorticoids, growth factors, thyroid hormones as well as a number of gonadal hormones including steroids and peptides (Schulz et al, 2010; Tovo-Neto et al, 2018; Fallah 2019, 2020, 2021; Ma et al, 2020a, b; Tovo-Neto et al, 2020; Li et al, 2020). A number of neurohormones including Gnih (Tsutsui et al, 2000) were shown to be involved in the control of pituitary gonadotropin production (Amano et al, 2006; Moussavi et al, 2012, 2013, 2014; Choi et al, 2016; Paullada-Salmerón et al, 2016; Muñoz-Cueto et al, 2017; Branco et., 2018; Ma et al, 2020 a, b) as well as being involved in paracrine control of gonadal function in fish (Fallah et al, 2019, 2020, 2021).…”

“…The relative number of spermatozoa per area was estimated as described by Fallah et al, (2019, 2020) and Tovo-Neto et al, (2020) using 20 different histological images (100x objective) per testicular explant. The images were analyzed in ImageJ software (National Institutes of Health, Bethesda, Maryland, http://rsbweb.nih.gov/ij), where background subtraction, threshold adjustment, and watershed separation of particles that resulted in a black and white picture of the highlighted spermatozoa were used to count the relative number of spermatozoa in the control and treatment groups.…”

“…In vertebrates, reproduction is under control of multiple signals from the brain-pituitary-gonadal axis (Habibi and Andreu-Vieyra, 2007; Nóbrega et al, 2010; Schulz et al, 2010; Tsutsui et al, 2010; Habibi et al, 2012; Tsutsui et al, 2013; Tovo-Neto et al, 2018; Tovo-Neto et al, 2020; Ma et al, 2020 a, b). The gonadotropin-releasing hormone (Gnrh) is one of the key players of the multifactorial regulation of reproduction due to its central role on stimulating the synthesis and secretion of the gonadotropin hormones.…”

Thyroid hormones deficiency impairs male germ cell development: a cross talk between hypothalamic-pituitary-thyroid, and - gonadal axes in zebrafish

“…The relative number of spermatozoa per area was quantified for each treatment. Twenty different fields were captured from a 100x objective lens and analyzed by IMAGEJ Software (available at http://imagej.nih.gov/ij/index.html) for quantification of spermatozoa number according to Fallah et al, (2019Fallah et al, ( , 2020, Tovo-Neto et al, (2020) and Rodrigues et al, (2021). This software allows quantification of several types of cells by limiting the size of the particle.…”