Benzoapyrene disrupts mouse preimplantation embryo development

Capsule:
Benzo(a)pyrene disrupts mouse preimplantation embryo development by increasing reactive oxygen species level, inducing genomic and telomeric DNA damage and cell apoptosis, and reducing inner cell mass ratio.

Authors:
Shaoquan Zhan, M.Sc., Xiya Zhang, Ph.D., Shanbo Cao, Ph.D., Junjiu Huang, Ph.D.

Volume 103, Issue 3, Pages 815-825

Abstract:

Objective:
To determine the effects of Benzo(a)pyrene (BaP) on the development of early preimplantation embryo by exposure to physiologic concentrations of BaP based on a previous report in human ovarian follicular fluid and serum.

Design:
Zygotes were cultured in 5 nM or 50 nM BaP and then examined for development efficiency, embryo quality, and DNA damage. In addition, embryonic stem cells (ESCs) were used as a model to test the toxic effects of BaP on inner cell mass (ICM) of blastocysts.

Setting:
Laboratory.

Animal(s):
CD1 mice.

Intervention(s):
Mouse zygotes and ESCs were cultured in medium with 5 nM or 50 nM BaP.

Main Outcome Measure(s):
The percentage (rate) of blastocyst development, reactive oxygen species level, and quality of embryos assessed by total cell number, cell apoptosis, Oct4- and Nanog-positive cell ratio, and DNA damage on genomic and telomeric DNA were compared between dimethyl sulfoxide control and BaP treatments.

Result(s):
The BaP-treated zygotes exhibited significantly higher reactive oxygen species activity, which might lead to more cell apoptosis, low ratio of Nanog- or Oct4-positive ICM cells, and increasing DNA damage in both genomic and telomeric DNA in blastocysts. By using mouse ESCs derived from ICM cells as a model, we showed that pluripotent cells might also show serious DNA damage after a brief exposure to BaP.

Conclusion(s):
Our data show that BaP could seriously disrupt cell growth and genomic DNA stability and increase cell apoptosis in mouse preimplantation embryo development.

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