Assessment of neurohepatic DNA damage in male Sprague–Dawley rats
exposed to organophosphates and pyrethroid insecticides
Marwa F. Ali
Received: 28 January 2018 / Accepted: 13 March 2018 /Published online: 23 March 2018
Springer-Verlag GmbH Germany, part of Springer Nature 2018
The current work was undertaken to test the genotoxic potential of chlorpyrifos (CPF), dimethoate, and lambda cyhalothrin
(LCT) insecticides in rat brain and liver using the single cell gel electrophoresis (comet assay). Three groups of adult male
Sprague–Dawley rats were exposed orally to one third LD
of CPF, dimethoate, or LCT for 24 and 48 h while the control group
received corn oil. Serum samples were collected for estimation of malondialdehyde (MDA) and glutathione peroxidase (GPx);
the brain and liver samples were used for comet assay and for histopathological examination. Results showed that signs of
neurotoxicity appeared clinically as backward stretching of hind limb and splayed gait in dimethoate and LCT groups, respec-
tively. CPF, LCT, and dimethoate induced oxidative stress indicated by increased MDA and decreased GPx levels. CPF and LCT
caused severe DNA damage in the brain and liver at 24 and 48 h indicated by increased percentage of DNA in tail, tail length, tail
moment, and olive tail moment. Dimethoate induced mild DNA damage in the brain and liver at 48 h. Histopathological changes
were observed in the cerebrum, cerebellum, and liver of exposed rats. The results concluded that CPF, LCT, and dimethoate
insecticides induced oxidative stress and DNA damage associated with histological changes in the brain and liver of exposed rats.
Insecticides are widely produced all over the world and used
for control of agricultural and household pests, which put
human and animals under the risk of exposure.
Manufacturing workers, field applicators, and the public are
exposed to insecticides by the use of synthetic insecticides
such as organophosphates (OP) and pyrethroids (Wang et al.
2011). Commonly used OP insecticides in Egypt include
chlorpyrifos (CPF) and dimethoate. Organophosphate pesti-
cides produce their effect on the nervous system by inhibition
of acetylcholinesterase (AChE) in cholinergic synapses and in
neuromuscular junctions (Wang 2002; Ballesteros et al. 2009).
Accumulation of AChE in the synapses results in death due to
asphyxia and loss of respiratory control, which attributed to
hyperactivity in cholinergic pathways (Sparling and Fellers
Dimethoate is a widely used insecticide and acaricide; it is
frequently used as systemic and contact pesticide. It is used on
agricultural crops and ornamental plants to control insects and
mites. Previous reports indicated that dimethoate caused cel-
lular injury, lipid peroxidation, free radicals release, and oxi-
dative stress in rats (Sharma et al. 2005; Singh et al. 2006).
Toxic effects of OP include genotoxicity, hepatic dysfunc-
tion, embryotoxicity, teratogenicity, neurochemical, and neu-
robehavioral changes (Goel et al. 2000). It was reported that
both acute and chronic exposures to CPF resulted in liver
damage in rats (Mansour and Mossa 2010; Elsharkawy et al.
2013;Ezzietal.2016). Furthermore, acute and subchronic
exposures to dimethoate caused pathological changes in the
brain and liver of rats (Astiz et al. 2009; Saafi et al. 2011).
Pyrethroid insecticides have a limited persistence in soil
and low toxicity to mammals and birds, which encouraged
their widespread application all over the world in agriculture
as a potent against pests (Glickman and Lech 1982;Kiddand
James 1991). Moreover, pyrethroid is used for the control of a
Responsible editor: Philippe Garrigues
* Doha Yahia
Department of Forensic Medicine and Toxicology, Faculty of
Veterinary Medicine, Assiut University, Assiut, Egypt
Department of Veterinary Pathology and Clinical Pathology, Faculty
of Veterinary Medicine, Assiut University, Assiut, Egypt
Environmental Science and Pollution Research (2018) 25:15616–15629