Mol. Hum. Reprod. Advance Access originally published online on June 27, 2009
Molecular Human Reproduction 2009 15(9):521-529; doi:10.1093/molehr/gap052
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New horizons for in vitro spermatogenesis? An update on novel three-dimensional culture systems as tools for meiotic and post-meiotic differentiation of testicular germ cells
1 Institute of Reproductive and Regenerative Biology of the Centre of Reproductive Medicine and Andrology, University Münster, Domagkstrasse 11 48129, Münster, Germany 2The Shraga Segal Department of Microbiology and Immunology, Faculty of Health Sciences and Soroka University Medical Centre, Ben-Gurion-University of the Negev, Beer-Sheva, Israel 3Present address: Pediatric Endocrinology Unit, Department of Women's and Children's Health, Astrid Lindgren Children's Hospital, Karolinska Institute, Stockholm, Sweden 4Present address: Department of Medicine, Endocrinology, Metabolism and Geriatrics, University of Modena and Reggio Emilia, Modena, Italy 5Present address: Covance Laboratories, Münster, Germany
6 Correspondence address. E-mail: stefan.schlatt{at}ukmuenster.de
Culture and differentiation of male germ cells has been performed for various purposes in the past. To date, none of the studies aimed at in vitro spermatogenesis has resulted in a sufficient number of mature gametes. Numerous studies have revealed worthy pieces of information, building up a body of information on conditions that are required to maintain and mature male germ cells in vitro. In this review, we report on previously published and unpublished experiments addressing murine germ cell differentiation in three-dimensional (3D) in vitro culture systems. In a systematic set of experiments, we examined the influence of two different matrices (soft agar and methylcellulose) as well as the need for gonadotrophin support. For the first time, we demonstrate that pre-meiotic male germ cells [revealed by the absence of meiotic marker expression (e.g. Boule)] obtained from immature mice pass through meiosis in vitro. After several weeks of culture, we obtained morphologically normal spermatozoa embedded in the matrix substance. Complete maturation relied on support from somatic testicular cells and the presence of gonadotrophins but appeared independent from the matrix in a 3D culture environment. Further research efforts are required to reveal the applicability of this culture technique for human germ cells and the functionality of the spermatozoa for generating offspring.
Key words: in vitro spermatogenesis/gonadotrophins/soft agarculture system (SACS)/methylcellulose culture system (MCS)
Submitted on May 7, 2009; resubmitted on June 12, 2009; accepted on June 19, 2009.