Purpose: To determine whether
epidermal growth factor (EGF) is involved in
reproductive developmental toxicity, using the embryonic
stem cell test (EST), as well as ascertain how EGF
influences embryonic development.
Methods: To predict developmental
toxicity on the basis of reducing cell viability and
inhibition of differentiation of embryonic stem cells,
EST was used to assess changes in different blastodermic
genes and expression of proteins including ectodermal-specific
genes Pax6, NF-H and glial fibrillary acidic protein (GFAP),
mesodermal-specific genes BMP4, GATA4, and MyoD, and
endodermal-specific genes, viz, α-fetoprotein,
transthyretin (TTR), and albumin, as well as
undifferentiated genes, Nanog and Oct4.
Results: The results indicate that
EGF was weakly embryotoxic with IC50ESC (i.e., the concentration that reduced ESC viability by
50 %), IC503T3 (the concentration that
reduced 3T3 cell viability by 50 %), and ID50ESC
(the concentration that inhibited
differentiation of ESC by 50 %) of 6.773, 10.531, and 1.793 μg/mL, respectively. The expression
levels of tissue-specific genes of the three germ layers
were mainly promoted by 0.01 - 1 μg/mL EGF.
Distinctively, relatively high concentrations of EGF
caused a discordant effect on the three germ layers.
High concentrations of EGF promoted differentiation of
the ectoderm and mesoderm, and either inhibited or had
mostly no impact on the endoderm.
Conclusion: The imbalance of the three
layer-specific genes and expression of proteins, as a
result of EGF, might be responsible for its weak level
of developmental toxicity. The sensitivity of TTR means
that further investigation is required to determine
whether it can be used as an embryotoxicity biomarker
for growth factors.
Keywords: Embryonic stem cell test,
Epidermal growth factor, Developmental toxicity, Germ
layers, Blastodermic genes, Protein expression