Motile human normozoospermic and oligozoospermic semen samples show a difference in double-strand DNA break incidence.
BACKGROUND
Among ICSI children de novo structural chromosome aberrations of male descent are increased. Misrepair of double-strand DNA breaks (DSBs) is a prerequisite for such aberrations to occur. To date, no absolute assessment of the number of DSBs in human sperm nuclei after gamete fusion has been described.


METHODS
Using man-mouse heterologous ICSI and gammaH2AX immunofluorescent staining, capable of detecting a single DSB, the number of lesions in ICSI selected sperm from normozoospermic men (n = 2) and oligozoospermic patients (n = 3) was quantified. A comparison with a subfertile male mouse model (n = 5) has been made. In addition, the fate of morphologically normal ejaculated immotile sperm after ICSI was examined.


RESULTS
A significant increase in the fraction of sperm cells bearing DSBs was found in oligozoospermic semen compared with that from normozoospermic men (P < 0.01). The majority of morphologically normal immotile human sperm showed excess gammaH2AX staining and nuclear disintegration. However, some had a non-deviant DSB pattern.


CONCLUSIONS
The increased fraction of DSB-positive sperm in both human and mouse oligozoospermic semen is adding to the surmise that semen from oligozoospermic patients has a reduced chromatin quality, causally related to reduced preimplantation embryo development. The use of ejaculated immotile sperm for in vitro reproduction is debatable due to sperm DNA degradation.
Derijck
Alwin A H A
AA
Department of Obstetrics and Gynaecology, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
van der Heijden
Godfried W
GW
Ramos
Liliana
L
Giele
Maud
M
Kremer
Jan A M
JA
de Boer
Peter
P
D000818:Animals; D002843:Chromatin / Q000737:chemistry / Q000648:ultrastructure; D042002:Chromatin Assembly and Disassembly; D004247:DNA / Q000032:analysis*; D053903:DNA Breaks, Double-Stranded; D053938:DNA Fragmentation; D047108:Embryonic Development; D006657:Histones / Q000235:genetics; D006801:Humans; D008297:Male; D051379:Mice; D009845:Oligospermia / Q000235:genetics* / Q000473:pathology; D012661:Semen / Q000737:chemistry*; D020554:Sperm Injections, Intracytoplasmic; D013081:Sperm Motility / Q000235:genetics*
D002843:Chromatin; C468783:H2AX protein, human; D006657:Histones; D004247:DNA