Oral Presentation The Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology 2014

Postnatal germ cell development during minipuberty in the mouse does not require androgen: implications for managing cryptorchidism (#46)

Ruili Li 1 2 , Amanda Vannitamby 1 , Jorien Meijer 3 , Bridget R Southwell 1 2 , John M Hutson 1 2 4
  1. F. Douglas Stephens Surgical Research Laboratory, Murdoch Childrens Research Institute, Parkville,, Victoria, Australia
  2. Department of Paediatrics, University of Melbourne, Parkville,, Victoria, Australia
  3. Medical School, , University of Groningen, Groningen, The Netherlands
  4. Urology Department, Royal Children’s Hospital, Parkville,, Victoria, Australia

Background: Undescended testis (UDT) causes an increased risk of infertility and malignancy resulting from aberrant germ cell (GC) development. Androgens are proposed to control early GC development.

Objective: To assess the effect of androgen on perinatal GC development in mice.

Material and Methods: Testes from androgen receptor knockout (ARKO) mice and wildtype (WT) littermates (n=3/group) were collected at embryonic (E) day 17 (day of virginal plug = E0), postnatal (P) days P0 (birth), P2, P4, P6, P8 and P10 for immunohistochemistry. Antibodies against mouse VASA homologue (MVH, GC marker), anti-Műllerian hormone (AMH, Sertoli cell marker), Ki-67 (proliferating cell marker), and DAPI (cell nuclei) were used and visualised by confocal microscopy. The numbers of GC/tubule, GC on the tubular basement membrane (GC/BM), Sertoli cells/tubule and the percentage of proliferating GC (Ki67+)/tubule and GC (Ki67+)/BM were counted. Data were analysed using t-test with software GraphPad Prism 5.02.

Results: In WT testes, GC/tubule decreased from E17 to P2, and then increased normally up to P10. Number of MVH + GC/tubule and GC on the BM were similar in ARKO and WT testes (p>0.05) at all time points. In addition, the percentages of proliferating GC (Ki-67+)/tubule and proliferating GC (Ki67+)/BM were similar at all time points (p>0.05) between ARKO and WT testes.

Conclusion: These results show that androgen does not control normal proliferation and migration of gonocytes from the centre of testicular tubules to BM, and putative transformation into type A spermatogonia, between birth and day 10 in mice. As this time interval spans normal ‘minipuberty’, which occurs between day 2 and day 6 in mice, it suggests that during murine minipuberty a novel, non-androgenic factor may stimulate early GC development. Identifying such a non-androgenic factor might be important for future medical therapy to improve fertility potential of boys with UDT and undergoing orchidopexy.