Vitrification has been widely used as an assisted reproductive technology in animals and humans, yet the impact of oocyte vitrification and warming on survival and histone modifications has to be evaluated. In the present study, the survival of mouse MII oocytes was assessed after freezing, as were changes in histone 3 lysine 9 (H3K9) dimethylation, histone 4 lysine 5 (H4K5) acetylation and histone 3 lysine 14 (H3K14) acetylation. The results show that, in oocytes subjected to vitrification, H3K9 methylation and H4K5 acetylation were increased. H3K14 acetylation could not be detected in either non-vitrified or vitrified oocytes. Oocytes are very sensitive to changes in H3K9 and H4K5 following vitrification. Both these histone modifications could be useful markers to monitor epigenetic perturbations induced by various experimental vitrification protocols and eventually for optimising the cryopreservation of human oocytes.

Male infertility is an important global health burden that can benefit from novel biomarkers and diagnostics innovation. Aberrant methylation of the imprinted genes H19 and SNRPN (small nuclear ribonucleoprotein polypeptide N) in sperm DNA has been implicated in abnormal sperm parameters and male infertility. However, whether certain methylation patterns of one or multiple CpG sites within an imprinted gene are pathological for multiple sperm defects remains poorly understood. To examine the diagnostic potential of certain methylation patterns of CpG sites for multiphenotype defects in human sperm, the sperm DNA methylation patterns of individual CpG sites within imprinting control regions (ICRs) of imprinted genes H19 and SNRPN were measured by bisulfite pyrosequencing in a Han Chinese population sample: 39 oligoasthenozoospermia (OA) patients, 36 asthenoteratozoospermia (AT) patients, and 50 normozoospermia (N) controls. A partial least squares discriminant analysis model was built with the CpG sites as independent variables. Among the 16 CpG sites screened, the methylation patterns of eight CpG sites within H19-ICR (CpG sites 1, 6-9, 12 and 15-16), and eight CpG sites within SNRPN-ICR (CpG sites 2, 5-6, 8-10, 13, and 16) correctly classified 74.4% and 72.0% of the samples in terms of male fertile status, respectively. Furthermore, by combination of these 16 selected CpG sites within ICRs of H19 and SNRPN, 88.0% of the samples could be successfully classified. Our study demonstrates that methylation profiles of CpG sites within ICRs of imprinted genes H19 and SNRPN may potentially serve as epigenomic biomarkers for assessment of infertility in men with multiple sperm defects. Further studies in independent population samples are called for diagnostic significance of methylation patterns of CpG sites within imprinted genes.

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Objective: To explore the possible significance of aromatase P450 in endometrial hyperplasia with a background of polycystic ovary syndrome (PCOS). Methods: Immunohistochemistry was used to determine the expression of aromatase P450 in endometrium of PCOS patients. Semiquantitative analysis of aromatase P450 expression of mRNA and protein level wasalso carried out by real-time quantitative RT-PCR method. After endometrial cells were stimulated by testosterone and letrozole in vitro, the estradiol (E 2 ) level was determined, and the expression of cell aromatase P450 mRNA was assessed. Results: The aromatase P450 mRNA level was increased in endometria of PCOS patients. When endometrial cells were cultured with 10 -6 M testosterone, the E 2 level in the culture medium increased. An inhibitory effect on E 2 generation and expression of aromatase P450 mRNA was observed when the endometrial cells were treated with 10 -5 M letrozole. Conclusions: There is an increased expression of aromatase P450 in PCOS patient endometrium. Androgen stimulation could enhance the synthesis of aromatase P450 mRNA and the production of E 2 in endometrial cells in vitro while letrozole could do the reverse.