Inducible and endothelial nitric oxide synthase: genetic background affects ovulation in mice.
OBJECTIVE
Inducible nitric oxide synthase (NOS) and endothelial NOS are involved in female reproductive physiology. We sought to investigate the influence of the inducible (Nos2) and endothelial (Nos3) NOS genes as a function of genetic background on ovulatory capacity and early embryonic development in a mouse model.


METHODS
Observational study of genetically altered mice and their response to a superovulation protocol.


METHODS
Academic research institution.


METHODS
Wild-type mice and mice deficient for Nos2 or Nos3 were bred to C57BL/6J and 129/Sv genetic backgrounds.


METHODS
Superovulation protocol, oocyte culture.


METHODS
Number of oocytes harvested, early embryonic development of zygotes, evaluation of ovarian histology.


RESULTS
The mean number of oocytes was significantly reduced in Nos3 deficient mice on a C57BL/6J background compared with controls. Oocytes deficient for Nos3 on a C57BL/6J background also showed reduced progression to two-cell stage embryos after 24 hours, two-cell stage embryos to blastocyst stage embryos, and survival to 48 hours. Those effects were distinctly absent in mice deficient for Nos3 on a 129/Sv background and in mice deficient for Nos2 on either genetic background.


CONCLUSIONS
Our data show that disruption of Nos2 had no effect on ovulation in our mice. The negative effect of Nos3 deficiency on ovulatory capacity and early embryonic development is modulated by genetic background. This suggests a role for strain-specific modifier genes in these processes.
Hefler
Lukas A
LA
Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas 77030, USA.
Gregg
Anthony R
AR
D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods; D005314:Embryonic and Fetal Development; D005260:Female; D005838:Genotype; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D019001:Nitric Oxide Synthase / Q000172:deficiency / Q000235:genetics*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009865:Oocytes / Q000166:cytology; D006080:Ovarian Follicle / Q000166:cytology; D010053:Ovary / Q000166:cytology; D010060:Ovulation / Q000235:genetics / Q000502:physiology*; D011247:Pregnancy; D013045:Species Specificity; D013480:Superovulation
D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse