Effects of dioxin, an environmental pollutant, on mouse blastocyst development and apoptosis.
OBJECTIVE
To evaluate the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin) on mouse embryo development and apoptosis.


METHODS
Controlled animal study.


METHODS
Academic research environment.


METHODS
Female mice (CB6F1) at 3 to 6 weeks of age and proven breeders (C578B46).


METHODS
Mouse embryos were obtained at the morula stage and cultured to the blastocyst stage in a pharmacologic dose of TCDD (3.1 microM) or a control medium. The morphology was assessed, and staining for apoptosis was performed. Immunohistochemistry for the presence of aromatic hydrocarbon receptor (AhR) was performed in another set of morula-stage embryos.


METHODS
The number of embryos developing from the morula to the blastocyst stage and number of apoptotic blastomeres in control vs. TCDD culture conditions.


RESULTS
No statistically significant differences were observed in the percentage of embryos reaching the blastocyst stage: 80.9% (115 of 142) in the TCDD-treated group, vs. 82.9% (121 of 146) in the control group. There was also no difference in the degree of apoptosis: 22.6 +/- 7.3% apoptotic cells (TCDD) vs. 25.3 +/- 9.7% (controls). Staining indicated the slight presence of aromatic hydrocarbon receptor in the morula-stage mouse embryos.


CONCLUSIONS
TCDD at 3.1 microM did not alter the development of early mouse morula to blastocysts and did not significantly induce apoptosis in vitro.
Matthews
M
M
Division of Reproductive Endocrinology, Rush Presbyterian St. Luke's Medical Center, Chicago, Illinois, USA. mmatthews@carolinas.org
Heimler
I
I
Fahy
M
M
Radwanska
E
E
Hutz
R
R
Trewin
A
A
Rawlins
R
R
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001755:Blastocyst / Q000187:drug effects* / Q000502:physiology*; D001757:Blastomeres / Q000187:drug effects / Q000502:physiology; D046508:Culture Techniques; D047108:Embryonic Development; D005314:Embryonic and Fetal Development / Q000187:drug effects; D004785:Environmental Pollutants / Q000494:pharmacology*; D005260:Female; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009028:Morula / Q000187:drug effects / Q000502:physiology; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology*; D011247:Pregnancy; D012016:Reference Values
D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins