Pregnancy environment, and not preconception, leads to fetal growth restriction and congenital abnormalities associated with diabetes.

Maternal diabetes can lead to pregnancy complications and impaired fetal development. The goal of this study was to use a mouse model of reciprocal embryo transfer to distinguish between the preconception and gestational effects of diabetes. To induce diabetes female mice were injected with a single high dose of streptozotocin and 3 weeks thereafter used as oocyte donors for in vitro fertilization (IVF) and as recipients for embryo transfer.

Testicular abnormalities in mice with Y chromosome deficiencies.

We recently investigated mice with Y chromosome gene contribution limited to two, one, or no Y chromosome genes in respect to their ability to produce haploid round spermatids and live offspring following round spermatid injection. Here we explored the normalcy of germ cells and Sertoli cells within seminiferous tubules, and the interstitial tissue of the testis in these mice. We performed quantitative analysis of spermatogenesis and interstitial tissue on Periodic acid-Schiff and hematoxylin-stained mouse testis sections.

Two genes substitute for the mouse Y chromosome for spermatogenesis and reproduction.

The mammalian Y chromosome is considered a symbol of maleness, as it encodes a gene driving male sex determination, Sry, as well as a battery of other genes important for male reproduction. We previously demonstrated in the mouse that successful assisted reproduction can be achieved when the Y gene contribution is limited to only two genes, Sry and spermatogonial proliferation factor Eif2s3y. Here, we replaced Sry by transgenic activation of its downstream target Sox9, and Eif2s3y, by transgenic overexpression of its X chromosome-encoded homolog Eif2s3x.

Mouse Y-Encoded Transcription Factor Zfy2 Is Essential for Sperm Formation and Function in Assisted Fertilization.

Spermatogenesis is a key developmental process allowing for a formation of a mature male gamete. During its final phase, spermiogenesis, haploid round spermatids undergo cellular differentiation into spermatozoa, which involves extensive restructuring of cell morphology, DNA, and epigenome. Using mouse models with abrogated Y chromosome gene complements and Y-derived transgene we identified Y chromosome encoded Zfy2 as the gene responsible for sperm formation and function.

Two Y genes can replace the entire Y chromosome for assisted reproduction in the mouse.

The Y chromosome is thought to be important for male reproduction. We have previously shown that, with the use of assisted reproduction, live offspring can be obtained from mice lacking the entire Y chromosome long arm. Here, we demonstrate that live mouse progeny can also be generated by using germ cells from males with the Y chromosome contribution limited to only two genes, the testis determinant factor Sry and the spermatogonial proliferation factor Eif2s3y.

Deficiency of the multi-copy mouse Y gene Sly causes sperm DNA damage and abnormal chromatin packaging.

In mouse and man Y chromosome deletions are frequently associated with spermatogenic defects. Mice with extensive deletions of non-pairing Y chromosome long arm (NPYq) are infertile and produce sperm with grossly misshapen heads, abnormal chromatin packaging and DNA damage. The NPYq-encoded multi-copy gene Sly controls the expression of sex chromosome genes after meiosis and Sly deficiency results in a remarkable upregulation of sex chromosome genes.

Short-term storage of human spermatozoa in electrolyte-free medium without freezing maintains sperm chromatin integrity better than cryopreservation.

Previous attempts to maintain human spermatozoa without freezing were based on short-term storage in component-rich medium and led to fast decline in motility and increased incidence of chromosome breaks. Here we report a new method in which sperm are maintained without freezing in an electrolyte-free medium (EFM) composed of glucose and bovine serum albumin. Human sperm were stored in EFM or human tubal fluid medium (HTFM) or were cryopreserved, and their motility, viability, and DNA integrity were examined at different intervals.

Paternal DNA damage resulting from various sperm treatments persists after fertilization and is similar before and after DNA replication.

In spite of its highly condensed state, sperm DNA is vulnerable to damage that can originate from oxidative stress, the activity of sperm-specific nucleases, or both. After fertilization, in the oocyte, paternal chromatin undergoes dramatic changes, and during this extensive remodeling, it can be both repaired and degraded, and these processes can be linked to DNA synthesis. Here, we analyzed sperm response to damage-inducing treatments both before and after fertilization and before or after zygotic DNA replication.

Deficiency in the multicopy Sycp3-like X-linked genes Slx and Slxl1 causes major defects in spermatid differentiation.

The human and mouse sex chromosomes are enriched in multicopy genes required for postmeiotic differentiation of round spermatids into sperm. The gene Sly is present in multiple copies on the mouse Y chromosome and encodes a protein that is required for the epigenetic regulation of postmeiotic sex chromosome expression. The X chromosome carries two multicopy genes related to Sly: Slx and Slxl1.

Deficiency in mouse Y chromosome long arm gene complement is associated with sperm DNA damage.

Background: Mice with severe non-PAR Y chromosome long arm (NPYq) deficiencies are infertile in vivo and in vitro. We have previously shown that sperm from these males, although having grossly malformed heads, were able to fertilize oocytes via intracytoplasmic sperm injection (ICSI) and yield live offspring. However, in continuing ICSI trials we noted a reduced efficiency when cryopreserved sperm were used and with epididymal sperm as compared to testicular sperm.

Live offspring from mice lacking the Y chromosome long arm gene complement.

The mouse Y chromosome long arm (Yq) comprises approximately 70 Mb of repetitive, male-specific DNA together with a short (0.7-Mb) pseudoautosomal region (PAR). The repetitive non-PAR region (NPYq) encodes genes whose deficiency leads to subfertility and infertility, resulting from impaired spermiogenesis.

Freezing-free preservation of human spermatozoa--a pilot study.

This study tested a method for maintaining human spermatozoa without freezing for subsequent use in intracytoplasmic sperm injection (ICSI). We demonstrated that human sperm stored in electrolyte-free solution maintain their motility and viability for at least 4 and 6 weeks, respectively. We also have shown that preserved spermatozoa are fully functional in ICSI.

Ejaculated and epididymal mouse spermatozoa are different in their susceptibility to nuclease-dependent DNA damage and in their nuclease activity.

Ejaculated mouse sperm retrieved from the uteri are more susceptible to DNA damage during freeze-drying and freezing without cryoprotection than epididymal sperm. This prompted us to speculate that a factor present in the uterus after mating, either male or female derived, was responsible for increased susceptibility of ejaculated sperm to DNA damage during preservation and that the differences between epididymal and ejaculated mouse sperm in response to stress originated from varying nuclease activity. We first exposed epididymal sperm to the uterine content from females mated to vasectomized males (UCSP), to the uterine content from unmated females in estrus (UC), and to the seminal vesicle fluid (SVF) and examined sperm chromosomes after intracytoplasmic sperm injection (ICSI).