64 Glyphosate and its formulation, Roundup, impair in vitro maturation of bovine cumulus-oocyte complexes and subsequent early embryonic development
A.-S. Fries A , N. Blad-Stahl A B , J. Beranek B , S. Mazurek B and C. Wrenzycki AA Chair for Molecular Reproductive Medicine, Clinic for Veterinary Obstetrics, Gynecology and Andrology, Justus-Liebig-University Giessen, Giessen, Germany
B Institute for Veterinary Physiology and Biochemistry, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany
Reproduction, Fertility and Development 35(2) 158-158 https://doi.org/10.1071/RDv35n2Ab64
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Glyphosate (Gly) is a nonselective systemic herbicide widely used worldwide. Gly is commonly applied as part of glyphosate-based herbicides (GBHs) including the best-known formulation, Roundup (R-Gly) (Bayer AG). There is some evidence that GBHs can act as an endocrine disruptor. Therefore, the purpose of this study was to evaluate the effect of different Gly and R-Gly concentrations supplemented during in vitro maturation (IVM) on maturation rates and subsequent embryo development. Furthermore, the steroidogenic activity of cumulus cells was determined measuring the concentrations of steroids (progesterone-P4, oestradiol-E2) in maturation medium (MM). Cumulus-oocyte complexes were isolated from abattoir-derived ovaries. Embryos were generated using a standard in vitro production (IVP) protocol. MM was supplemented with 0 (control), 30 or 300 µg/mL of pure Gly or R-Gly at the same glyphosate-equivalent concentrations. After 24 h of maturation, maturation rates were determined via Hoechst staining and maturation medium was used for steroid analyses via RIA. Cleavage/developmental rates were recorded at Day 7 (Day 0 = IVF) via morphological microscopic evaluation. Maturation rates did not differ significantly between oocytes of the different treatment groups (75.5–81.1%). Cleavage rates were significantly decreased for embryos stemming from oocytes that were matured with 300 µg/mL R-Gly (36.2% ± 16.6) compared with those of all other groups (67.1–78.5%). The same holds true for the developmental rates at Day 7 (5.6 ± 2.4 vs 22.5–30.0%) and Day 8 (5.6 ± 2.4 vs 22.9–32.9%). Furthermore, a significant P4 and E2 increase was detected in MM from the 300 µg/mL R-Gly group compared with those of the other maturation groups. These data indicate that although exposure to pure glyphosate and Roundup during in vitro maturation does not affect nuclear maturation, R-Gly does impair oocyte developmental competence in terms of cleavage and development up to Day 8. Moreover, R-Gly at the same glyphosate-equivalent concentrations was shown to be more toxic than pure glyphosate, reducing embryo development and altering steroidogenesis.
