Abstract
Fertility is abolished in nonbreeding males in colonies of natal naked mole-rats (NMRs). Although spermatogenesis occurs in both breeding and nonbreeding male NMRs, the mechanisms underlying the differences in fertility between breeders and nonbreeders remain unexplored. In this study, a significant decrease in autophagy was observed in Leydig cells of the testis from nonbreeding male NMRs. This alteration was visualised as a significant decrease in the levels of autophagy-related gene 7 (Atg7), Atg5, microtubule-associated protein 1A/B light chain 3 (LC3-II/I) and the number of autophagosomes and an increase in P62 levels using Western blotting analyses. Furthermore, monodansylcadaverine (MDC) staining and Western blot analyses revealed that testosterone production decreased in nonbreeding male NMR Leydig cells, this decrease was associated with a reduction in autophagy. Primary Leydig cells from breeding and nonbreeding male NMRs were processed to investigate the effect of an autophagy inhibitor (3-MA, 3-methyladenine) or an autophagy activator (rapamycin) on testosterone production. Rapamycin induced an increase in testosterone production in NMR Leydig cells, whereas 3-MA had the opposite effect. Consequently, spermatogenesis, the weight of the testis, and androgen levels were dramatically reduced in nonbreeding male NMRs. While rapamycin treatment restored the fertility of nonbreeding male NMRs. Based on these results, inadequate autophagy correlates with a decrease in steroid production in nonbreeding male NMR Leydig cells, which may ultimately influence the spermatogenesis and fertilities of these animals.
Highlights
The naked mole-rat (Heterocephalus glaber; naked mole-rats (NMRs)) is a highly eusocial rodent that inhabits East Africa
According to the results of histological examinations, both nonbreeding and breeding male NMRs possess a large number of Leydig cells and sparsely distributed seminiferous tubules (STs); fewer STs were observed in breeding male NMRs
Macrophages are located along the tubules and regulate the ability of undifferentiated spermatogonia to differentiate and proceed through spermatogenesis, but only spermatogonia and other sperm cells at different stages were calculated for investigations on the structures of STs
Summary
The naked mole-rat (Heterocephalus glaber; NMR) is a highly eusocial rodent that inhabits East Africa. One breeding female (the queen) and 1–3 breeding males are present in an NMR colony. Fertility has been shown to be suppressed in nonbreeding, mature female NMRs, but this suppression is reversible [5]. Suppressed females share similarities with juvenile mammals of other species [6] and mammals in which reproductive activity is suspended during seasonal anestrus [7, 8]. Some nonbreeding males have active sperm [5]. The hypothalamic–pituitary gonadal axis plays critical roles in male reproductive organs and the endocrine system controls the secretion of androgens and spermatogenesis.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
