Developmental stress and lead (Pb): Effects of maternal separation and/or Pb on corticosterone, monoamines, and blood Pb in rats

Abstract

The level of lead (Pb) exposure in children has decreased dramatically since restrictions on its use were implemented. However, even with restrictions, children are exposed to Pb and still present with cognitive and behavioral deficits. One prominent aspect of the exposome of these children is that many come from low social economic status (SES) conditions, and low SES is associated with stress. In order to compare the combined effects of early stress and Pb, Sprague-Dawley rats were exposed to vehicle or Pb either alone or in combination with maternal separation stress during brain development (i.e., postnatal day (P)4 to P11, 19, or P28). Maternally separated/isolated pups had lower body and thymus weights during exposure and had increased levels of blood Pb compared with vehicle controls. Isolation, but not Pb, affected the response to an acute stressor (standing in shallow water) when assessed on P19 and P29, but not earlier on P11. Interactions of Pb and isolation were found on monoamines in the neostriatum, hippocampus, and hypothalamus on turnover but not on levels, and most changes were on dopamine turnover. Isolation had greater short-term effects than Pb. Interactions were dependent on age, sex, and acute stress.

Multiple regulatory aspects of histone methyltransferase EZH2 in Pb-induced neurotoxicity

“…Pb is a pervasive environmental threat that continues to compromise human health on a global scale [ 1 , 2 ]. Despite its ubiquitous presence, Pb is a chemically xenobiotic element with no known essential function in cellular growth, proliferation or physiological function [ 3 , 4 ].…”

Health Risk Assessment of Heavy Metals Accumulated on PM2.5 Fractioned Road Dust from Two Cities of Pakistan

“…Pb exposure can affect human health in various ways such as neurological disorders in children, malfunction of kidneys, cardiovascular problems, genotoxicity, and disruption of stress mechanisms which can cause neurotoxicity [ 56 , 57 ]. Incidental ingestion and inhalation of soil/dust particles are considered major sources of Pb exposure in human beings [ 57 ].…”

A Hypothesis of the Interaction of the Nitrergic and Serotonergic Systems in Aggressive Behavior Induced by Exposure to Lead

“…The exposure to environmental pollutants as a predisposition factor of violent behavior has received little attention since violent and antisocial behaviors are usually attributed to socioeconomic factors, including poverty, deficient education and family instability. There is evidence that violent behavior is more frequent among individuals with low intellectual quotient (Amos-Kroohs et al, 2016 ), a neurobehavioral pattern that has been described in children exposed to Pb at an early stage. Recently, Sampson and Winter ( 2018 ) published an article about the social consequences of exposure to lead, highlighting criminal behavior in young people exposed to lead, and suggesting that some factors can be explained through the hypothesis of displacement of Ca ++ by Pb ++ (Sampson and Winter, 2018 ).…”

“…In pregnant women, it has been reported that Pb can cross the placental barrier and is equally distributed in the mother and fetus (Fontana et al, 2013 ). Children are the most susceptible population to Pb exposure: they have been reported to show alterations in cardiac function, encephalopathy, genotoxicity, cognitive deficits, language alterations, antisocial behavior and juvenile delinquency after exposure to the metal (Amos-Kroohs et al, 2016 ; Sampson and Winter, 2018 ). Evidence suggests that the rate of violent crimes in several countries is related to the levels of Pb in blood among the population, even in individuals at school age.…”

“…The Mexican government has passed bills related to the production and evaluation of ceramic (Norma Oficial Mexicana, 2007 ) as well as a program encouraging ceramic producers to use alternative unleaded glaze in pottery (National Program to Adopt Lead-Free Glazed Pottery, FONART, Mexico). Despite these actions, the levels of Pb in blood among the population are a concern mainly because of the levels of Pb in the environment, (Fontana et al, 2013 ; Amos-Kroohs et al, 2016 ), the easy access of the metal to the body and the manufacturers’ non-compliance with official standards (Norma Oficial Mexicana, 2007 ; Diaz-Ruiz et al, 2017 ). Therefore, Pb remains an environmental risk in countries like Mexico regardless of the restrictions in its use.…”