Apoptosis in human unfertilized oocytes after intracytoplasmic sperm injection.
OBJECTIVE
To investigate the presence of programmed cell death in unfertilized oocytes after intracytoplasmic sperm injection (ICSI), assuming that previous apoptotic events could be correlated with the fertilization failure.


METHODS
Comparison of the rate of DNA fragmentation in human oocytes at different stages of maturation soon after pick-up (control) and in unfertilized oocytes after ICSI treatment.


METHODS
In vitro fertilization (IVF) laboratory with extensive ICSI experience.


METHODS
Sixty-three patients undergoing assisted fertilization by ICSI.


METHODS
Terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling (TUNEL) assay and anticaspase-3 cleaved immunoassay to detect apoptosis in control and ICSI-treated oocytes.


METHODS
Differences in the percentage of oocytes demonstrating DNA fragmentation between control oocytes and unfertilized ICSI treated oocytes at different stages of maturation.


RESULTS
The DNA fragmentation, by TUNEL assay, appeared in all the immature control oocytes, but only 37% of mature oocytes showed DNA fragmentation. This DNA fragmentation was observed in 88.8% of the oocytes unfertilized after ICSI; furthermore, DNA fragmentation appeared as well in the sperm injected into the cytoplasm.


CONCLUSIONS
The study has shown DNA fragmentation in human oocytes unfertilized after ICSI. The evidence is confirmed as well in control oocytes, free from in vitro culture or manipulation stress. Caspase-3 immunoassay suggests the presence of apoptosis. The high percentage of oocytes demonstrating DNA fragmentation in the unfertilized oocytes could be correlated with fertilization failure.
Bosco
Liana
L
Dipartimento Materno-Infantile, University of Palermo, Palermo, Italy.
Ruvolo
Giovanni
G
Morici
Giovanni
G
Manno
Maurizio
M
Cittadini
Ettore
E
Roccheri
Maria C
MC
D017209:Apoptosis / Q000502:physiology*; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D053938:DNA Fragmentation / Q000502:physiology*; D005260:Female; D006801:Humans; D009865:Oocytes / Q000166:cytology* / Q000502:physiology*; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*