Sperm vacuoles were exclusively nuclear. In our selected teratozoospermic population, aneuploidy and chromatin condensation defects were the main alterations observed in SLV. Based on results from this small sample of spermatozoa, we propose a global impairment of the spermatogenesis process as a common origin of the morphological alterations.

ABSTRACT:Numerous parameters have to be tested to identify optimal conditions for prepubertal testicular tissue banking. Our study evaluated 19 different cryopreservation conditions for immature testicular tissue using a rapid screening method. Immature mice testes were cryopreserved using either 1,2-propanediol (PROH) or dimethyl sulfoxide (DMSO) at a concentration of 0.75 or 1.5 M using a controlled slow-cooling rate protocol with (S+) or without seeding (S2). Equilibration was performed either at room temperature or at 4uC for 15 or 30 minutes. Seminiferous cord cryodamage was determined by scoring morphologic alterations. Cell proliferation ability was evaluated using a proliferating cell nuclear antigen (PCNA) antibody. Testes cryopreserved with optimal conditions were grafted into immunodeficient mice. The highest proportions of PCNA-positive nuclei and lowest morphologic alterations were observed with 1.5 M DMSO. Tissues were more altered with 0.75 M DMSO or PROH. Complete germ cell maturation was observed after allografting of testicular pieces previously frozen with 1.5 M DMSO, S2, 30 minutes. The 1.5 M DMSO, S+ or S2 protocol preserved prepubertal mice testicular tissue architecture and germ cell and Sertoli cell proliferation potential. Allografting of thawed testis fragments into immunodeficient mice confirmed that the 1.5 M DMSO, S2, 30 minutes protocol maintained testicular somatic and germ cell functions. Postthaw histologic evaluation and PCNA immunostaining are useful to rapidly test numerous freeze-thaw parameters. They may also be efficient tools to control human prepubertal frozen testis quality, within the context of a clinical application.

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Testicular tissue cryopreservation is the only potential option for fertility preservation in pre-pubertal boys exposed to gonadotoxic treatment. Completion of spermatogenesis after in vitro maturation is one of the future uses of harvested testicular tissue. The purpose of the current study was to evaluate the effects of vitamin A on in vitro maturation of fresh and frozen-thawed mouse pre-pubertal spermatogonial stem cells in an organ culture system. Pre-pubertal CD1 mouse fresh testes were cultured for 7 (D7), 9 (D9) and 11 (D11) days using an organ culture system. Basal medium was supplemented with different concentrations of retinol (Re) or retinoic acid (RA) alone or in combination. Seminiferous tubule morphology (tubule diameter, intra-tubular cell type), intra-tubular cell death and proliferation (PCNA antibody) and testosterone level were assessed at D7, D9 and D11. Pre-pubertal mouse testicular tissue were frozen after a soaking temperature performed at -7°C, -8°C or -9°C and after thawing, were cultured for 9 days, using the culture medium preserving the best fresh tissue functionality. Retinoic acid at 10-6M and retinol at 3.3.10-7M, as well as retinol 10-6M are favourable for seminiferous tubule growth, maintenance of intra-tubular cell proliferation and germ cell differentiation of fresh pre-pubertal mouse spermatogonia. Structural and functional integrity of frozen-thawed testicular tissue appeared to be well-preserved after soaking temperature at -8°C, after 9 days of organotypic culture using 10-6M retinol. RA and Re can control in vitro germ cell proliferation and differentiation. Re at a concentration of 10-6M maintains intra-tubular cell proliferation and the ability of spermatogonia to initiate spermatogenesis in fresh and frozen pre-pubertal mouse testicular tissue using a soaking temperature at -8°C. Our data suggested a possible human application for in vitro maturation of cryopreserved pre-pubertal testicular tissue.

SUMMARYHuman normal spermatozoa present a specific chromatin organization, illustrated particularly by the non-random chromosome positioning. Spermatozoa with large vacuoles, described using motile sperm organelle morphology organization (MSOME), are associated with nuclear alterations, such as abnormal chromatin condensation and aneuploidy. To question a probable association between large nuclear vacuoles and chromatin disorganization, we evaluated chromosomes X, Y and 18 topography in normal spermatozoa (NS) compared with spermatozoa with large vacuoles (SLV). After centrifugation on a gradient density system, 229 NS (spermatozoa presenting a normal nuclear shape and a vacuole area <6.5% of head area) from 10 normal semen samples and 221 SLV (spermatozoa presenting a vacuole area >13% of head area) from 10 semen samples with teratozoospermia were selected using MSOME. A three-colour FISH was carried out using a-satellite centromeric probes for chromosomes X, Y and 18. For each chromosome, longitudinal and spatial positioning of centromeres was analysed. Distribution of each chromosome was non-random in NS and in SLV, whatever the methodology used. Using longitudinal positioning, distribution of chromosome 18 and chromosome Y centromeres did not differ significantly between SLV and NS. On the contrary, chromosome X centromeres were more frequently positioned in the posterior region of sperm nucleus in SLV (p = 0.01). Considering spatial positioning, distributions differed significantly between SN and SLV for chromosome Y (p = 0.02) and chromosome 18 (p < 10 À4) and marginally for chromosome X (p = 0.08). Our study concluded to a modification in chromosomes X, Y and 18 centromere topography between NS and SLV, representing a novel and supplementary evidence to argue chromatin disorganization in SLV.