High rate of premature chromosome condensation in human oocytes following microinjection with round-headed sperm: case report.
A young couple proceeded to three ICSI treatment cycles because of male infertility. The semen samples varied between 10 x 10(6) and 36 x 10(6)/ml, 38 and 51% progressive motility but 0% normal morphology. Different types of sperm heads, mostly round-headed with varying spherical appearance (86%) were presented beside acephalic sperm (pinheads; 12%), both one- or two-tailed and the former also without a tail. Very few sperm (2%) exhibited slightly oval-shaped heads. Electron microscopy revealed the absence of the acrosome combined with disturbance of the chromatin condensation among the round-headed sperm. In all three cycles, the fertilization rate using the round-headed sperm fraction was very low with the best result of 2/18 (11%) two-pronucleate oocytes and one one-pronucleate oocyte obtained in the second ICSI cycle. The three oocytes cleaved and were transferred in the 3-4-cell stage without achieving a pregnancy. Of the 29 unfertilized and prepared oocytes from the last two cycles, 27 were informative and revealed the maternal metaphase II chromosomes in the haploid range and a high rate (85%) of premature chromosome condensation (PCC) of the sperm nucleus with remarkable variation in the degree of condensation. Thus, it appears that nearly all round-headed sperm from this patient were incapable of oocyte activation after ICSI, which could be due to non-release (or absence) of an activating factor. As a consequence, PCC was induced in the sperm nuclei by the chromosome condensing factors which were still active in the oopasm of the arrested oocytes.
Schmiady
Hardi
H
Charite--Universitätsmedizin Berlin, Campus Mitte, Klinik für Frauenheilkunde und Geburtshilfe-Reproduktionsmedizin, Germany. hardi.schmiady@charite.de
Schulze
Wolfgang
W
Scheiber
Ingrid
I
Pfüller
Bettina
B
D002877:Chromosomes, Human / Q000235:genetics*; D005260:Female; D006801:Humans; D007248:Infertility, Male / Q000235:genetics / Q000473:pathology*; D008297:Male; D008845:Microinjections; D009865:Oocytes / Q000502:physiology*; D010375:Pedigree; D013077:Sperm Head / Q000473:pathology*; D020554:Sperm Injections, Intracytoplasmic; D013084:Sperm-Ovum Interactions / Q000235:genetics*; D017211:Treatment Failure