Epigenetic modifications in the offspring after spermatogonial stem cell transplantation

Student thesis: Master's Thesis

Abstract

Background: Mouse spermatogonial stem cell transplantation (SSCT) has become an established research model to study the testicular germ cell line. By performing SSCT in mice, donor spermatogenesis can be re-established in the seminiferous tubules of an otherwise infertile recipient. Transplanted males are able to produce fertile offspring after spontaneous mating.
Therefore, SSCT is a promising fertility preservation technique for prepubertal boys who are exposed to gonadotoxic treatments, leading to infertility.
Compared to the increasing reports illustrating the effectiveness of SSCT in reproductive terms only few studies addressed safety issues. Before accepting SSCT as a clinical strategy, all potential safety concerns need to be carefully evaluated.
In the present project, we investigated whether epigenetic modifications occur in the correct way during early embryogenesis and during spermatogenesis in offspring.
Material & Methods: We evaluated the general methylation, using immunohistochemistry for 5-methylcytosin (5-MC), in level in pre-implantation embryos of different stages (2-cell, 4-cell, multi-cell, morula and blastocyst) from GFP- transplanted mice with GFP+ testicular donor cells, We also analyzed the acetylation of H4K8.
Stainings for 5-MC, DNMT3a, H4K5ac and H4K8ac were also performed on testicular tissue from live born GFP+ male offspring of transplanted mice.
Results: Unfortunately, no GFP+ embryos could be obtained from the transplanted males. The GFP+ offspring showed a correct pattern for H4K5ac and H4K8ac in the spermatids, but some abnormalities were seen in the spermatocytes. No major differences were indicated for DNMT3a and 5-MC compared to fertile adult controls.
Conclusion: No major abnormalities on epigenetic level were observed, and the ones observed do not seem to cause anything severe. Anyway, it is still necessary to repeat the embryo experiment to check possible epigenetic problems during embryo development. Therefore even though SSCT has potential as a clinical application, more research is required before becoming a fertility preservation technique.
Date of Award2013
Original languageEnglish
SupervisorEllen Goossens (Promotor) & Dorien Van Saen (Co-promotor)

Keywords

  • fertility preservation
  • epigenetic modifications
  • pre-implantation embryos
  • spermatogenesis
  • spermatogonial stem cell transplantation

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