[Analysis of sperm chromosomes in infertile males with teratozoospermia].

Objectives: The aim of the study was to examine sperm chromosomes from infertile males with teratozoospermia.

Design: Basic research study

Materials And Methods: Spermatozoa were obtained from infertile males with teratozoospermia. Intracytoplasmic sperm injection was used to inject human spermatozoa into mouse oocytes in order to examine sperm chromosomes.

Expression of foreign DNA is associated with paternal chromosome degradation in intracytoplasmic sperm injection-mediated transgenesis in the mouse.

The efficiency of intracytoplasmic sperm injection (ICSI)-mediated transgenesis is often limited by poor embryo development. Because our previous work indicated that impairment of embryo development is frequently related to chromosomal abnormalities, we hypothesized that foreign DNA and/or conditions used to enhance integration of the DNA might induce chromosome damage. Therefore, we examined the chromosomes of mouse embryos produced by transgenesis with the EGFP gene.

Combination of dithiothreitol and detergent treatment of spermatozoa causes paternal chromosomal damage.

Treatment of spermatozoa with either the nonionic detergent Triton X-100 (TX) or dithiothreitol (DTT) has been suggested to confer enhanced success on intracytoplasmic sperm injection (ICSI) in mice and humans. Here, we attempted to use both reagents together, to our knowledge for the first time, and found that this caused severe chromosomal breaks in paternal pronuclei. We documented this effect further by treating mouse spermatozoa with several combinations of DTT with and without detergent.

Intracytoplasmic sperm injection is more efficient than in vitro fertilization for generating mouse embryos from cryopreserved spermatozoa.

Efficient and dependable mouse cryopreservation methods are urgently needed because the production of mice with transgenes and disrupted and mutant genes is now commonplace. Preservation of these unique genomes provides an essential safeguard for future research. Unfortunately, mouse spermatozoa appear more vulnerable to freezing than other species, e.

Sperm nuclear halos can transform into normal chromosomes after injection into oocytes.

Mouse sperm nuclei extracted with an ionic detergent and 2 M NaCl retain their overall morphology, but upon subsequent reduction of the protamine disulfides they lose all elements of chromatin structure except the organization of DNA into loop that are anchored to the nuclear matrix. These DNA loops appear as a halo surrounding the nuclear matrix, and nuclei extracted in this manner are, therefore, called nuclear halos. Here, we report that sperm nuclear halos injected into oocytes can form pronuclei, then transform into chromosomes with normal morphology.

Separation of motile populations of spermatozoa prior to freezing is beneficial for subsequent fertilization in vitro: a study with various mouse strains.

Success with in vitro fertilization (IVF) using inbred strains of mice varies considerably and appears to be related to the proportion of motile spermatozoa present in epididymal sperm samples of different strains. In this study, motile spermatozoa were separated from the original samples using a column of Sephadex G25. IVF rates were compared between separated and nonseparated samples of epididymal spermatozoa before and after cryopreservation.