Genistein, the main isoflavone present in soy, affects the reproductive processes due to a potent steroidogenic action.
Intrauterine exposure to genistein is able to affect the reproductive system of offspring, stimulate uterine cancer and cause
changes in testicular epithelium. To understand the effects of genistein on in vitro embryo production, we aimed to evaluate
the effects of genistein during COCs maturation on the production and quality of bovine in vitro-produced embryos. Therefore,
ovaries from a local slaughterhouse were obtained and COCs were recovered and divided into three groups: control group
(no genistein addition); GEN 100 (100 μM of genistein); and GEN 500 (500 μM of genistein). Concentrations were based on
previous studies and tested by a pilot study. All the experimental groups contained the same base medium with 0.1 mM
dimethyl sulfoxide (DMSO). The COCs were in vitro matured for 24 hours. After maturation, we submitted COCs to in vitro
fertilization for 18 hours. Further, presumptive zygotes remained to in vitro culture for seven days. To evaluate the effects
of genistein on IVEP we analyze the blastocyst yield and expression of genes related to embryo quality. The genes related
to embryo quality observed were OCT4 (Octamer-binding transcription factor 4), PLAC8 (Placenta associated 8), and CDX2
(Caudal type homeobox 2); normalized with PPIA (Peptidylprolyl isomerase A - housekeeping gene). We analyzed the effect
of oocyte exposure to genistein using ANOVA. Means were compared by orthogonal contrast and we considered different
when P<0.05. For in vitro embryo production, we figure out (P<0.0001) that 500μM of genistein decreases blastocyst yield
(13.05%) compared to GEN 100 group (46.11%) and control group (46.87%). Furthermore, GEN 500 group demonstrated lower
OCT4 mRNA abundance compared to control group (P<0.05). On the other hand, genistein did not affect CDX2 expression
(P=0.21). Taken together, we concluded that addition of 500 μM of genistein during COCs maturation impairs in vitro embryo
development and down-regulates a key gene related to inner cell s mass differentiation and embryo implantation.