Exposure to Paraquat (PQ) has been linked to Parkinsonism in both experimental animals and humans. PQ is widely used among other herbicides in developing countries, where its safe use has been proven to be impossible. This action has resulted in farmers' fatal poisonings with PQ and threatens public health. The present study was designed to investigate the role of PQ induced neurotoxicity in the sustantia Nigra, striatal and cerebellar neurons in addition to the neuroprotective potentials of Selenium (Se) and Magnesium (Mg) in abrogating PQ-induced neurotoxicity in mice. We used rotarod test to access PQinduced motor coordination deficit in mice. We also determined: PQ-induced mild cognitive impairment using Morris water maze to check for spatial memory in mice, PQ-induced oxidative stress by investigating lipid peroxidation level of malonyl dialdehyde (MDA) and glutathione peroxidase (GSH) and measuring the activities of superoxide dismutase (SOD), and catalase (CAT) in the brain of PQ-induced mice. The histomorphological outcome of the nigrostriatal neurons and cerebellum were also accessed in PQinduced experimental mice. Immunoreactivity of nigrostriatal dopaminergic neurons to thyroxine hydroxylase (TH) was accessed to determine dopamine loss in the nigrostriatal neurons. In addition, we determine selenium and magnesium's antioxidative effect on paraquat-induced Parkinsonism in mice by checking their effects on motor coordination, cognition, MDA, SOD, CAT, and GSH levels and assessing their ameliorating effect on dopaminergic neurons of the nigrostriatal system and in cerebellar neurons using both the neurons' histomorphological outline and their affinity to TH. Generally, our results showed that PQ induces Parkinsonism in mice by inducing oxidative stress, degenerative cell death in the SNpc, striatum, and cerebellum and by inducing dopamine depletion in SNpc and striatum which resulted in motor and cognitive deficits. Se and Mg also proved to be good antioxidants ameliorating PQ-induced neurodegenerative effects but combine dose of Se and Mg caused further neuronal degeneration on PQinduced mice. Se and Mg may be promising therapeutic targets for PD management in addition to L-dopa treatment since patients from developing countries may not afford deep brain stimulation (DBS) and optogenetics used in the management of PD.Keywords: Paraquat, Parkinsonism, Selenium, Magnesium, Oxidative stress, sustantia Nigra, striatum, cerebellum, motor coordination, cognition.
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