A New Technique for the Cytogenetic Study of Human Oocytes

Abstract

A technique for making good quality chromosome preparations from human oocytes is described. Analyzable good Quality chromosomes were present in human oocytes that were hypotonically treated and fixed. Ninety-eight oocytes were processed. Chromosome analysis could be performed on 80 (82%) oocytes. Seven oocytes showed an absence of chromosomes, mainly due to degeneration. Chromosome analysis could not be performed on 11 oocytes because the chromosome number could not be determined. Of 80 analyzable preparations, a 63% (50) incidence of aneuploidy with/without premature chromosome condensation was observed in the human oocytes that failed to fertilize in vitro with 3:4 ratios of hypo and hyperhaploidy. Our method presented in this study gives an excellent scattering of nuclei and metaphase plates in one layer as well as a good spreading of chromosomes. It may be applied to all stages of human oocytes in IVF-ET programs. This method can also be useful in pre-embryo biopsy and in secondhand quality control for an IVF-ET program. This may help resolve the present limitations of oocyte chromosome preparation and analysis, and therefore lead to further improvements in germ cell cytogenetics.