A detailed cytogenetic analysis of large numbers of fresh and frozen-thawed human sperm after ICSI into mouse oocytes.
BACKGROUND
Since information about chromosome aberrations in micro-manipulated sperm is still inadequate, cytogenetic analysis was performed on large numbers of fresh and frozen-thawed (FT) human sperm after injection into mouse oocytes. The effects of the ICSI procedure on oocytes are also discussed based on analysis of the mouse chromosome complements.


METHODS
After the injection of fresh and FT human sperm into mouse oocytes, chromosomes of the hybrid oocytes were analysed at first cleavage metaphase.


RESULTS
Incidences of the hybrid oocytes at the first cleavage metaphase were significantly different between fresh (71.5%) and FT sperm groups (80.1%) (P < 0.05). The chromosome analysis of 477 fresh and 141 FT sperm showed no difference in the incidences of aneuploidy (1.6/0.7%), structural aberrations (8.8/7.8%) or diploidy (0.0/0.0%) between these categories. The cytogenetic result did not differ from our previous result using IVF between human sperm and hamster oocytes. In an additional cytogenetic study on 615 mouse chromosome complements, the incidence of diploidy (5.4%) was significantly higher than those (0.3-2.8%) in the previous mouse cytogenetic studies, and the hybrid oocytes with no mouse chromosomes (2.0%) existed.


CONCLUSIONS
This result suggests that the ICSI procedure induces no sperm chromosome aberrations but increases numerical aberrations in oocyte chromosome complements.
Watanabe
Seiji
S
Department of Anatomy, Hirosaki University School of Medicine, 5 Zaifucho, Japan. sage@cc.hirosaki-u.ac.jp
D000782:Aneuploidy; D000818:Animals; D002869:Chromosome Aberrations; D006224:Cricetinae; D015925:Cryopreservation; D020732:Cytogenetic Analysis; D004171:Diploidy; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007621:Karyotyping; D008297:Male; D051379:Mice; D009865:Oocytes / Q000502:physiology / Q000648:ultrastructure; D012662:Semen Preservation; D020554:Sperm Injections, Intracytoplasmic; D013094:Spermatozoa / Q000648:ultrastructure*