Glyphosate-based herbicide induces hyperplastic ducts in the mammary gland of aging Wistar rats

Abstract

Adverse effects of glyphosate-based herbicide (GBH) exposure on endocrine-related tissues have been reported. Our aim was to determine whether early postnatal exposure to a GBH produces long-term effects on the mammary gland. Female Wistar pups were injected with saline solution (Control) or GBH (2 mg glyphosate/kg/day) on postnatal days (PND) 1, 3, 5 and 7. At 20 months old, mammary gland and serum samples were collected. 17β-estradiol and progesterone serum levels were assessed. In the mammary gland, histomorphological features, proliferation index and steroid hormone receptors expression, by immunohistochemistry, were determined. GBH exposure produced morphological changes evidenced by a higher percentage of hyperplastic ducts and a fibroblastic-like stroma in the mammary gland. A high expression of steroid hormone receptors were detected on hyperplastic ducts in GBH treated rats. The results indicate that an early postnatal exposure to GBH produced long-term consequences disrupting the mammary gland morphology of aging female rats.