Neonatal Phytoestrogen Exposure Alters Oviduct Mocosal Immune Response to Pregnancy and Affects Preimplantation Embryo Development in the Mouse Brooke Salehzadeh And Shakara Maggitt
What are Phytoestrogens? Phytoestrogens are a class of plant-derived estrogenic compounds Phytoestrogens are not naturally produced by the endocrine system but enter the body through consumption Phytoestrogens are similar in structure to estradiol which is the form of estrogen present in mammals Phytoestrogens bind to cell-surface estrogen receptors alpha and beta Classified as an endocrine disrupting chemicals.
Phytoestrogens Continued Where are phytoestrogens found? In soy-based products like peanuts and cereal grains Soy-based foods contain a class of phytoestrogens called isoflavones The major isoflavones in soy-based foods are genistein and daidzein Genistein and daidzein are linked to disruptions in reproduction
Genistein, Daidzein and Estradiol Structural Similarities Genistein Daidzen 17-Beta Estradiol
Effects of Phytoestrogen were first noticed In 1946 when sheep grazing on red clover pastures became infertile Rams became feminized and unable to breed Ewes were unable to support a pregnancy to full-term Ewes also had cervical thickening that prevented copulation and cervical mucus that thicken enough to prevent sperm mobility Similar observations were made in cows that were fed silage made primarily of red clover and captive cheetahs who were fed a soy-based diet.
Previous Findings and Hypothesis A previous study demonstrated that oviducts of genistein-treated mice are posteriorized as compared to control mice oviducts What does posteriorized mean? They express numerous genes normally restricted to posterior regions of the female reproductive tract (FRT), the cervix and vagina. Altered inflammatory responses in the oviduct environment during early pregnancy explained the poor survival of pre-implantation embryos in this region of mammalian female reproductive tract
Sub-Hypotheses What genes are posteriorized after genistein treatment? When is their expression changed? Can estrogen-receptor antagonist reverse genistein effects?
Materials and Methods: Animals and Treatment Female pups were injected subcutaneously on postnatal days 1-5 with corn oil (control) or genistein, 50 mg/kg/day, ICI, 1.0 mg/kg/day, or ICI 1mg/kg/day and genistein 50 mg/kg/day The dosing treatment of genistein was chosen for this experiment because it results in a serum genistein concentration in a similar range as measured in infants fed soy-based infant formula. Females around 6-8 weeks underwent Superovulation alone Superovulation and mating Mated with vasectomized males What is superovulation? A term used to describe the drug-induced production of multiple eggs at one time
Results
Results Figure.1
Results Figure 2 Control Genistein treated Control Genistein treated
Results Continued Figure 3 A B
Results Continued Figure 4
Results Continued Figure 5
Figure 6 Figure 6
Conclusion Exposure to low levels of estrogenic environmental chemicals or to phytoestrogens during sensitive developmental windows can alter the balance between FRT mucosal immunity and FRT support of fertilization and preimplantation embryo development.
Conclusion Continued Postnatal exposure to genistein results in an overall upregulation of inflammatory and inflammatory regulating genes. Increase in immune response due to increase IgA concentrations and immune response genes Phytoestrogen exposure to the female fetus, infant, child and adolescent human has the potential to impact female mucosal immunity and fertility.
Limitations Pregnancies were terminated after day 4... Why is this an issue? Blastocysts were only transferred to control Picked genes they knew would be effected What about other genes? In females treated with ICI, how will it effect normal estrogen activities? No effects in future offspring can be observed What other limitations do you think there are?
Implications for Humans With an increase number of clinically infertile couples and the cause of infertility remaining undermined, exposure to phytoestrogenic compounds like genistein and daizden could be a probable cause. In humans, the late first trimester and full second trimester is the time window of female reproductive tract development when regional and cellular differentiation occurs More human studies need to be conducted to determine the long-term effects phytoestrogens could have on both males and females. These studies should most likely be conducted in neonate and infants since the phytoestrogens appears to have a greater effect during the critical developmental window of the neonate. Can the use of pluripotent stem cells in possible future human studies be valuable?
Are there any questions?