Detection of X- and Y-bearing human spermatozoa after motile sperm isolation by swim-up.
OBJECTIVE
To assess the ratio of X- to Y-bearing human spermatozoa in motile fractions isolated by the swim-up technique.


METHODS
The proportions of X- and Y-bearing sperm were determined in neat semen samples (control) and in motile fractions isolated from the same samples by swim-up. X- and Y-bearing sperm were simultaneously identified using chromosome-specific DNA probes and double fluorescence in situ hybridization.


METHODS
Hospital-based university department.


METHODS
Ten healthy donors with normal semen characteristics.


METHODS
The distribution of haploid cells (X or Y), normal size cells with two sex chromosome (XX, YY, or XY), and large cells containing two (XX, YY, or XY) or four (XXYY) sex chromosomes were measured in neat semen samples and in motile fractions prepared by swim-up.


RESULTS
Overall, 95% of sperm in the neat semen and swim-up fractions were labeled with the probes. The ratios of X- to Y-bearing sperm were 47.3:46.9 (neat semen) and 48.4:47.1 (swim-up fractions), which were not significantly different from a 1:1 ratio. The frequencies of sperm with normal size nuclei and two sex chromosomes (XX, YY, or XY) in the swim-up fractions were not significantly different from the controls, but there was a significant reduction in the proportion of cells with large nuclei and two (XX, YY, or XY) or four (XXYY) sex chromosomes in the swim-up fractions.


CONCLUSIONS
The swim-up technique does not selectively enrich either X- or Y-bearing sperm. Because the isolation of motile spermatozoa is an important procedure for routine IUI, IVF-ET, and GIFT, the results of this study are important reassurance that the sex ratio is not altered by this method of sperm preparation.
Han
T L
TL
Department of Obstetrics and Gynaecology, University of Adelaide, Queen Elizabeth Hospital, Woodville, South Australia.
Flaherty
S P
SP
Ford
J H
JH
Matthews
C D
CD
D002467:Cell Nucleus / Q000648:ultrastructure; D015342:DNA Probes; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D011003:Ploidies; D013081:Sperm Motility; D013094:Spermatozoa / Q000648:ultrastructure*; D014960:X Chromosome; D014998:Y Chromosome
D015342:DNA Probes