These data show that ICSI with testicular spermatozoa provides the first efficient assisted reproduction treatment option for men with high levels of sperm DNA damage.

No abstract

BACKGROUND:The recent development of a computer-assisted polarization microscopy system (Polscope) with which the meiotic spindle can be visualized in living oocytes on the basis of its birefringence permits analysis of the meiotic spindles of oocytes subjected to ICSI. Previous studies have shown that the meiotic spindle is not always aligned with the ®rst polar body (PB) in metaphase II human oocytes prepared for ICSI. In the present study, the relationship between the degree of meiotic spindle deviation from the ®rst PB location and ICSI outcome was analysed. METHODS: Oocytes were divided into four groups according to the angle of meiotic spindle deviation from the PB position. The angle of deviation was 0±5°, 6±45°, 46±90°and >90°for groups I to IV respectively. RESULTS: The rates of normal [2 pronuclei (PN)] and abnormal (1PN or >2PN) fertilization did not differ between groups I, II and III. However, the rate of normal fertilization was lower among oocytes in which the meiotic spindle deviation angle was >90°; this led to an increased proportion of tripronucleated zygotes that failed to extrude the second PB. When embryos developed from normally fertilized oocytes were evaluated on day 3 after ICSI, no relationship was found between the angle of meiotic spindle deviation and embryo quality. The meiotic spindle was not detected in only 9% of oocytes, and these showed a higher incidence of fertilization and cleavage abnormalities than did oocytes in which the spindle was detected. When oocytes at metaphase I after cumulus oophorus and corona radiata removal were matured in vitro, the meiotic spindle was detected in 53.8% of those that reached metaphase II. In these in-vitro-matured oocytes the meiotic spindle was always aligned with the ®rst PB, suggesting that misalignment seen in those oocytes matured in vivo resulted from PB displacement during manipulations for cumulus and corona removal. CONCLUSION: High degrees of misalignment between the meiotic spindle and the ®rst PB predict an increased risk of fertilization abnormalities. However, when normal fertilization had occurred, the cleavage potential of embryos developing from such oocytes was not impaired. These ®ndings facilitate the selection of oocytes for ICSI in situations when the creation of supernumerary embryos is to be avoided.Key words: ICSI/meiotic spindle/oocyte quality/polar body/Polscope Introduction The orientation of the injection channel and the sperm deposition site during ICSI are usually chosen with regard to the position of the ®rst polar body, assuming that the meiotic spindle with metaphase chromosomes is located in a nearby region of the oocyte cytoplasm. However, recent observations made with the use of a novel orientation-independent polarized microscopy system (Polscope), coupled with image processing software enabling the visualization of meiotic spindles in living oocytes, have shown that the ®rst polar body position does not predict accurately the location of the meiotic spindle in

The current techniques of oocyte freezing and thawing inevitably cause meiotic spindle destruction. All spindles observed in thawed oocytes result from post-thaw reconstruction.

Oral antioxidant treatment appears to improve ICSI outcomes in those patiens with sperm DNA damage, in whom this treatment reduces the percentage of damaged spermatozoa.