Neonatal exposure to a glyphosate based herbicide alters the development of the rat uterus.

GUERRERO SCHIMPF M; MILESI MM; INGARAMO P; MUÑOZ DE TORO M; LUQUE EH; VARAYOUD J

Congreso; 9th Congress of Toxicology in Developing Countries and XIX Congress of Toxicology; 2015

Introduction: Glyphosate-based herbicides (GBH) are non-selective and broad-spectrum herbicides widely used in agriculture to control weeds. In vitro and in vivo studies have reported endocrine disrupting effects and male reproductive toxicity at puberty and adulthood caused by GBH exposure. However no reports are available regarding its effects on the development and performance of the female reproductive tract.Objective: To evaluate the effects of neonatal exposure to a GBH on uterine morphology, proliferation and expression of proteins that regulate uterine organogenetic differentiation in rats.Material and Methods: Female Wistar pups received saline solution (control, C) or an environmental relevant dose of commercial formulation of glyphosate (GBH, 2 mg/kg) by sc injection in the nape of the neck every 48 h from postnatal day (PND) 1 to PND7. Pups were sacrificed on PND8 (neonatal period) and PND21 (prepubertal period) to evaluate acute and short-term effects, respectively. The uterine histomorphology was evaluated using hematoxylin and eosin staining. The epithelial and stromal immunophenotypes were determined by immunohistochemistry (IHC) against luminal epithelial protein (cytokeratin 8; K8), stratified epithelial proteins (p63 and pan cytokeratin -K1, -K5, -K10 and -K14); and vimentin (a cytoskeletal protein expressed in fibroblastic cells). In addition we determined the uterine cell proliferation by detecting the immunohistochemical expression of Ki-67 protein. Further we evaluated the expression of estrogen receptor alpha (ERa), progesterone receptor (PR) and Hoxa10 by IHC in all uterine compartments (LE: luminal epithelium, GE: glandular epithelium, SS: subepithelial stroma, M: myometrium), to investigate possible changes in key proteins that regulate uterine organogenetic differentiation.Results and Discussion: The GBH-exposed uteri showed different gross morphological changes.The most relevant change was the luminal epithelial hyperplasia (75% of animals on PND8 and 37.5% on PND21). The epithelial cells showed a positive immunostaining for K8 and the stromal cells for vimentin. GBH-treated group showed an increase cellular proliferation in the LE and SS on PND8, without changes on PND21. In addition, the uterine organogenetic differentiation was affected at both ages. An induction of PR and Hoxa10 was detected in all cellular compartments from GBH-treated rats on PND8 and ERa was also up regulated in the SS. The deregulation of PR and Hoxa10 persisted on PND21.Conclusions: Neonatal exposure to GBH disrupts the postnatal uterine development and alters the expression of proteins involved in uterine organogenetic differentiation at the prepubertal period. All these alterations may impact the functional differentiation of the uterus, affecting the female fertility and/or promoting the development of neoplasias.Acknowledgements: Financial support from the Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT, PICT 2011-1491), CONICET (PIP 2011, 11220110100494) and the Universidad Nacional del Litoral (CAI + D 2011, 501 20110100423 LI)