Successful metaphase chromosome analysis of human elongated spermatids using mouse oocytes

Abstract

Human elongated spermatids from azoospermic patients were inserted into mouse oocytes by intracytoplasmic sperm injection (ICSI). The injection resulted in survival rates of 46.5% (180 out of 387) and activation rates of 36.1% (65 out of 180). The rate of two pronuclear (2PN) formation was 35.4% (23 out of 65). Only 34.8% (eight out of 23) metaphase chromosome spreads from 2PN zygotes could be analysed; however, all were of normal karyotype. Cytogenetic analysis at the first metaphase revealed that human elongated spermatid chromosomes were able to undergo replication in a heterogeneous environment.

Use of mouse oocytes to evaluate the ability of human sperm to activate oocytes after failure of activation by intracytoplasmic sperm injection

“…In a previous study, injected human sperms activated mouse oocytes, which developed to the first mitotic metaphase stage through the 2PN stage (Rybouchkin et al, 1995). Using this phenomenon of mouse oocytes, several investigators have reported karyological diagnoses of human sperms or spermatids (Rybouchkin et al, 1995;Lee et al, 1996;Araki et al, 1999;Ogawa et al, 2000). In order to evaluate the usefulness of ICSI into mouse oocytes, in the present study we injected mouse oocytes with mouse or human sperms.…”

“…It was reported that most fertilization failures following ICSI resulted in non-activated oocytes (Sousa & Tesarik, 1994;Tesarik & Sousa, 1995). Using this phenomenon of mouse oocytes, several investigators have reported karyological diagnoses of human sperms or spermatids (Rybouchkin et al, 1995;Lee et al, 1996;Araki et al, 1999;Ogawa et al, 2000). On the other hand, several investigators have reported the usefulness of artificially activating oocytes to achieve fertilization after prior fertilization attempts had failed (Nakagawa et al, 2001;Zhang et al, 1999).…”

Visualization of human sperm chromosomes by using mouse oocytes cryothawed after enucleation

“…Because it was reported by Rybouchkin et al (1) that human sperm chromosomes can be analyzed by intracytoplasmic sperm injection (ICSI) into mouse oocytes, whereby a human sperm injected into a mouse oocyte forms a pronucleus and advances to the metaphase stage of the first cleavage division, mouse oocytes generally have been used for analyses of human sperm chromosomes (2)(3)(4)(5)(6)(7). However, it sometimes is difficult to identify human sperm chromosomes precisely in samples that also include mouse oocyte chromosomes.…”