Impact of chronic exposure to the pesticide chlorpyrifos on respiratory parameters and sleep apnea in juvenile and adult rats

Abstract

The widely used organophosphorus pesticide chlorpyrifos (CPF) is often detected in food. CPF inhibits acetylcholinesterase and can modify muscle contractility and respiratory patterns. We studied the effects of chronic exposure to CPF on respiratory parameters and diaphragm contractility in 21- and 60-days old rats. Pregnant rats were exposed to oral CPF (1 or 5 mg/ kg /day: CPF-1 or CPF-5 groups vs vehicle: controls) from gestation onset up to weaning of the pups that were individually gavaged (CPF or vehicle) thereafter. Two developmental time points were studied: weaning (day 21) and adulthood (day 60). Whole-body plethysmography was used to score breathing patterns and apnea index during sleep. Then, diaphragm strips were dissected for the assessment of contractility and acetylcholinesterase activity. Results showed that the sleep apnea index was higher in CPF-exposed rats than in controls. In adult rats, the expiratory time and tidal volume were higher in CPF-exposed animals than in controls. At both ages, the diaphragm’s amplitude of contraction and fatigability index were higher in the CPF-5 group, due to lower acetylcholinesterase activity. We conclude that chronic exposure to CPF is associated with higher sleep apnea index and diaphragm contractility, and modifies respiratory patterns in sleeping juvenile and adult rats.

Impacts of prolonged chlorpyrifos exposure on locomotion and slow-and fast- twitch skeletal muscles contractility in rats

“…The effect of organophosphate pesticide on skeletal contractile characteristics has been reported previously but mainly for the diaphragm [33,34] and not typically for fast and slow twitch muscles. Our study investigated the findings observed in vivo in locomotory activity to the properties observed in vitro of the two types of skeletal muscles edl , and soleus.…”

Chlorpyrifos induces genotoxic effects in human leukocytes in <i>vitro</i> at low concentrations

“…Chlorpyrifos (CPF) is one of the most commonly used pesticides that belongs to the class of organophosphates whose primary toxic mechanism has been inferred to involve acetylcholinesterase inhibition. However, there is limited information regarding the CPF-induced genotoxic effect in human cells, particularly in normal cells (Darwiche et al, 2018). Nonetheless, Želježić et al (2017) have described that CPF is safe at doses of up to 3 μg mL -1 without causing significant DNA damage or carcinogenicity in human lymphocytes.…”

“…However, the literature is imprecise regarding the concentration of CPF that is capable of inducing genotoxicity (Zhu et al, 2015). In fact, few studies have demonstrated the genotoxic effect associated with CPF in human tissues or cells as well as the concentration capable of inducing this effect (Okonko, Ikpeme, & Udensi, 2016;Darwiche et al, 2018). Therefore, the range of concentration of CPF that is capable of inducing genotoxic effects remains yet unsolved (Ali et al, 2009).…”

Sleep in honey bees is affected by the herbicide glyphosate

“…The knowledge about the impact of these substances in the animal resting behaviour is sparse. Only one previous study reported induction of sleep apnea in rats exposed to the insecticide chlorpyrifos 24 . One of the widest agrochemicals used worldwide is the herbicide glyphosate (GLY) 25 .…”