Fluoride exposure during pregnancy and lactation triggers oxidative stress and molecular changes in hippocampus of offspring rats

Ecotoxicol Environ Saf. 2021 Jan 15:208:111437. doi: 10.1016/j.ecoenv.2020.111437. Epub 2020 Oct 20.

Abstract

Long-term exposure to high concentrations of fluoride (F) can damage mineralized and soft tissues such as bones, liver, kidney, intestine, and nervous system of adult rats. The high permeability of the blood-brain barrier and placenta to F during pregnancy and lactation may be critical to neurological development. Therefore, this study aimed to investigate the effects of F exposure during pregnancy and lactation on molecular processes and oxidative biochemistry of offspring rats' hippocampus. Pregnant Wistar rats were randomly assigned into 3 groups in accordance with the drinking water received: G1 - deionized water (control); G2 - 10 mg/L of F and G3 - 50 mg/L of F. The exposure to fluoridated water began on the first day of pregnancy and lasted until the 21st day of breastfeeding (when the offspring rats were weaned). Blood plasma samples of the offspring rats were collected to determine F levels. Hippocampi samples were collected for oxidative biochemistry analyses through antioxidant capacity against peroxyl (ACAP), lipid peroxidation (LPO), and nitrite (NO2-) levels. Also, brain-derived neurotrophic factor (BDNF) gene expression (RT-qPCR) and proteomic profile analyses were performed. The results showed that exposure to both F concentrations during pregnancy and lactation increased the F bioavailability, triggered redox imbalance featured by a decrease of ACAP, increase of LPO and NO2- levels, BDNF overexpression and changes in the hippocampus proteome. These findings raise novel questions regarding potential repercussions on the hippocampus structure and functioning in the different cognitive domains.

Keywords: BDNF; Fluoride; Neurotoxicity; Offspring; Oxidative stress; Proteomic.

MeSH terms

  • Animals
  • Antioxidants / metabolism
  • Brain-Derived Neurotrophic Factor
  • Environmental Pollutants / toxicity*
  • Female
  • Fluorides / metabolism
  • Fluorides / toxicity*
  • Hippocampus / drug effects*
  • Hippocampus / growth & development
  • Lactation
  • Lipid Peroxidation / drug effects
  • Male
  • Oxidative Stress / drug effects
  • Oxidative Stress / physiology*
  • Pregnancy
  • Prenatal Exposure Delayed Effects / metabolism
  • Proteome / metabolism
  • Proteomics
  • Rats
  • Rats, Wistar

Substances

  • Antioxidants
  • Brain-Derived Neurotrophic Factor
  • Environmental Pollutants
  • Proteome
  • BDNF protein, human
  • Fluorides