Morphological changes in the mammary gland of aged Wistar rats postnatally exposed to a glyphosate-based herbicide

GASTIAZORO MP; VARAYOUD J; ZANARDI MV; GUERRERO SCHIMPF M; MILESI MM; MUÑOZ-DE-TORO M; DURANDO M

Dresden

Simposio; International Research Alumni Symposium. Efficacy and safety of the use of natural compounds ? progress through ?omics? technologies and CRISPR/Cas.; 2019

Introduction:Glyphosate-based herbicides (GBHs) have been one of the most intensive herbicide used over the last three decades. Although commercial formulations of glyphosate include other chemical compounds, which are classified as inert compounds, the formulations of glyphosate have been proved to be more toxic than the compound in its technical grade.Objective:The aim of this study was to determine whether exposure to a low-dose of a GBH during early postnatal development impacts negatively on the mammary gland (MG) structure of aged female rats.Methodology:All animal handling and experimental protocols were approved by the Ethical Committee of the FBCB (UNL). Female Wistar pups were injected subcutaneously with saline solution (Control, C; n=8) or GBH using the reference dose (2 mg/kg/day; n=10) on postnatal days 1, 3, 5, and 7. Along the experiment, animals were weighed each treatment day including 24 h after the end (ie: PND1, 3, 5, 7 and 8) and then body weight was recorded weekly or monthly. Animals were sacrificed at 20 months of age, MG and blood samples were collected. 17β-Estradiol (E2) and progesterone (P4) serum levels were measured. In the MG we evaluated the histomorphology of the epithelial and stromal compartment, the proliferation index and the expression of estrogen receptor alpha (ESR1)and progesterone receptor (PR) in epithelial cells.Results:Along the experiment, GBH-exposed rats showed a tendency to a lower body weight, but no significant differences in body weight gain were found between C and GBH-treated females from birth to adulthood.In GBH rats, the relative ratio of duct/alveoli (C: 3.80 ± 1.28% vs GBH: 13.82 ± 3.99%; p