Chromosomal analysis of human oocytes fertilized by microinjection of spermatozoa into the perivitelline space

Abstract

In-vitro fertilization by sperm microinjection techniques have been shown to be effective (the birth of one child has resulted), but concerns about the chromosomal normality of embryos derived from this process have been raised. The British Interim Licensing Authority has set, as a pre-condition to the clinical application of sperm microinjection, the chromosomal evaluation of pre-embryos derived by this technique. In this study, we demonstrate that four of 18 (22%) eggs fertilized by sperm microinjection into the perivitelline space are chromosomally abnormal as compared with nine of 30 (30%) fertilized by conventional IVF procedures. These results are not significantly different. In addition, we demonstrate that nine out of 20 couples who did not previously have fertilization in multiple cycles of IVF had between one and three oocytes fertilized by sperm microinjection. These findings demonstrate that sperm microinjection does not increase the incidence of chromosomally abnormal eggs and provide reassurance and support for the clinical implementation of a technique that appears to be effective for the treatment of certain forms of male infertility.

Cytogenetic analysis of human oocytes after subzonal insemination

“…Martinet al (1988) have reported a dramatic increase in structural chromosomal abnormalities after microinjection of sonicated human spermatozoa into the cytoplasm of hamster eggs. Kola et al, (1990) have demonstrated that 4 out of 18 (22 per cent) eggs were chromosomally abnormal after subzonal insemination compared with 9 out of 30 conventionally in vitro fertilized eggs (30 per cent). There was no increase of chromosomal abnormalities in their series of microinjected eggs.…”

Comparison of Blastulation and Pregnancy Rates of Fertilized Human Oocytes Obtained after Conventional In Vitro Fertilization and Intracytoplasmic Sperm Injection.

“…Although an earlier report demonstrated that sperm microinjection does not increase the incidence of chromosomally abnormal embryos [16], it is well known that the frequency of chromosomal abnormalities is high in preimplantation embryos and that most abnormal embryos are lost before pregnancy is recognized clinically [13]. Furthermore, these oocytes are exposed to hyaluronidase, intense light, and fluctuations in temperature and are subjected to the creation of an artificial breach in the zona pellucida and oolemma.…”

Cytogénétique des ovocytes humains : 40 ans de progrès

“…Ainsi, dans la plupart de ces études, les auteurs se sont limités à une simple classification par taille des chromosomes, après coloration au Giemsa. Seules quelques études ont eu recours à une technique de marquage spécifique des chromosomes (bandes Q ou bandes R), afin d'améliorer leur identification [15][16][17]. Le caractère approximatif de ces études a été confirmé par les travaux de R. Angell qui démontra que la séparation pré-maturée des chromatides homologues au cours de l'anaphase I constituait un type fréquent d'erreurs de ségrégation méiotique, jusqu'ici passé inaperçu dans les ovocytes humains [18][19][20].…”