Germ cell proliferation and apoptosis in the developing human ovary.
BACKGROUND
The regulation of germ cell proliferation and loss during human ovarian development is poorly understood. This is of particular interest at the time leading up to the formation of primordial follicles, at 18 wk gestation onward.


OBJECTIVE
The objective of the study was to identify and quantify germ cell proliferation and apoptosis and expression of caspases in the human fetal ovary.


METHODS
This study was a laboratory investigation.


METHODS
The study was conducted at a research institute.


METHODS
Cell proliferation and apoptosis were detected using immunohistochemical localization of phosphorylated histone H3 and cleaved caspase-3, respectively. Caspases were also detected by immunoblotting.


RESULTS
The overall proportion of germ cells in mitosis remained constant between 14 and 19 wk but showed increasing clustering. Caspase-2, -3, -7, -8, and -9 were detected by immunoblotting. There was a significant increase in germ cell apoptosis. A specimen of 20 wk gestation showed similar phosphorylated histone H3 but markedly lower cleaved caspase-3 expression than earlier gestations. Cleaved caspase-3 was not expressed in oocytes that had formed primordial follicles.


CONCLUSIONS
These results indicate that as primordial follicle formation is initiated and progresses, there is an increase in both mitotic activity and apoptosis of those germ cells that have not reached the apparently protective environment of the primordial follicle.
Fulton
N
N
Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, University of Edinburgh, Chancellors' Building, 49 Little France Crescent, Edinburgh EH16 4SB, United Kingdom.
Martins da Silva
S J
SJ
Bayne
R A L
RA
Anderson
R A
RA
D017209:Apoptosis / Q000502:physiology*; D020169:Caspases / Q000378:metabolism; D002452:Cell Count; D002455:Cell Division / Q000502:physiology; D005260:Female; D006657:Histones / Q000378:metabolism; D006801:Humans; D008938:Mitosis / Q000502:physiology; D010053:Ovary / Q000166:cytology* / Q000196:embryology*; D010063:Ovum / Q000166:cytology* / Q000201:enzymology; D010766:Phosphorylation; D011247:Pregnancy
D006657:Histones; D020169:Caspases