Recent studies have reported that induced pluripotent stem （iPS） cells from mice and humans can differentiate into primordial germ cells. However, whether iPS cells are capable of producing male germ cells is not known. The objective of this study was to investigate the differentiation potential of mouse iPS cells into spermatogonial stem cells and late-stage male germ cells. We used an approach that combines in vitrodifferentiation and in vivotransplantation. Embryoid bodies （EBs） were obtained from iPS cells using leukaemia inhibitor factor （LIF）-free medium. Quantitative PCR revealed a decrease in Oct4 expression and an increase in StraSand Vasa mRNA in the EBs derived from iPS cells, iPS cell-derived EBs were induced by retinoic acid to differentiate into spermatogonial stem cells （SSCs）, as evidenced by their expression of VASA, as well as CDH1 and GFRal, which are markers of SSCs. Furthermore, these germ cells derived from iPS cells were transplanted into recipient testes of mice that had been pre-treated with busulfan. Notably, iPS cell-derived SSCs were able to differentiate into male germ cells ranging from spermatogonia to round spermatids, as shown by VASA and SCP3 expression. This study demonstrates that iPS cells have the potential to differentiate into late-stage male germ cells. The derivation of male germ cells from iPS cells has potential applications in the treatment of male infertility and provides a model for uncovering the molecular mechanisms underlying male germ cell development.
Objective To determine the correlation between semen parameters, sperm DNA damage, progressive motility （PR）, morphology and intrauterine insemination （IUI）/ intracyto- plasmic sperm injection （ICSI） outcomes. Methods All the donors providing the samples in this study were recruited by Shang- hai Human Sperm Bank. For IUI, 122 donors were divided into group A （n=60） and group B （n=62）. Group A had a higher pregnancy rate while group B had a lower pregnancy rate （3.86 ± 1.50% vs 0.18 ± 0.52%）. For ICSI, 45 donors were divided into group C with a higher pregnancy rate （77. 78 ± 17.21%, n=23）, group D with a lower pregnancy rate （40. 73 ± 19.19%, n=22） and group E with an average preg- nancy rate in the sperm bank （48.96 ± 12.08%, n=23）. Semen analysis, morphology and DNA damage were assessed on samples retained in the sperm bank. Fresh semen samples were also collected and corresponding semen analyses data was included along with the pregnancy rates. Results No significant difference was found in the population characteristics between groups A and B, while there was a significant difference in sperm DNA fragmetation index （DFI） and morphology between the two groups （P〈0.05）, but not in other semen parameters （P〉0.05）. There was no significant difference in population characteristics between groups C, D and E while the DFI of group D was significant higher than groups C and E （P〈0.01）, but there was no significant difference in other semen parameters （P〉0.05）.Conclusion DFI might be a good predictor for IUI outcomes. Infertile couples with a high DFI should choose ICSI treatment instead of IUI. DFI should be a routine screening marker used to screen for sperm donors.
