Use Of Paraquat Research Articles

Paraquat, Parkinson's Disease, and Agnotology.

Paraquat, Parkinson's Disease, and Agnotology.

Paraquat poisoning, what we should know

Paraquat (PQ) a brown syrupy liquid also known as methyl viologen is a commonly used herbicide in India. A highly toxic compound to humans, although, a large majority of fatalities from PQ poisoning are suicides. Accidental exposure is causing immense harm to farmers and agriculture workers, which is not documented. Accidental or deliberate ingestion has an extremely high case-fatality rate, and clinical features are due to generating reactive oxygen species which cause cellular damage ultimately leading to multiorgan failure. At present there is no antidote to PQ poisoning, various treatment modalities from immunosuppressants to antioxidants are used with no clear clinical efficacy. Elimination methods such as haemodialysis and haemoperfusion when done early have shown to be useful in few studies. Recently drug-like Edaravone and Perfenidone are being used but with no survival benefit. Neither proper information nor training on the use of PQ and personal protective equipment are provided by agriculture offices to farmers leading to accidental exposure. Hence paraquat use has been restricted in many parts of the world and an appeal for a ban in India is underway as a need for preventive measures.

Immunotoxicity Induced by Acute Subtoxic Doses of Paraquat Herbicide: Implication of Shifting Cytokine Gene Expression toward T-Helper (TH)-17 Phenotype

Paraquat (PQ) is a free radical-inducing agent commonly used as an herbicide. This study assesses the acute immunotoxicity of PQ in BALB/c mice and examines its effect on cytokine gene expression profile. It was found that single subtoxic oral doses of 2, 4, and 20 mg/kg significantly inhibited the in vitro mitogen-induced proliferation in both T and B cells. Also, such acute doses have resulted in significant reduction of the IgM plaque-forming cells counts. The impact of PQ on the cytokine gene expression of in vitro PHA-activated splenocytes was assessed at 2.0 and 0.006 μg/mL. The concentrations used in vitro represent the lowest in vivo dose given in this study and FAO-WHO set PQ acceptable daily intake (ADI) dose, respectively. Interestingly, the RT²-PCR array for common cytokines' expression demonstrated that PQ had markedly elevated the mRNA expression of several proinflammatory cytokines at both concentrations. More importantly, at concentrations equivalent to ADI, PQ had caused a marked up-regulation of IL-17 cytokine family including IL-17B, C, E, and F. Also, PQ has up-regulated mRNA expression of the T(H)-17-promoting cytokines IL-9 and -21. Together, these results show that PQ at higher concentrations can deplete immune functions, but at lower concentrations, it has potential to alter immune responses toward the proinflammatory profiles as that of T(H)-17. Such a T cell helper profile has been implicated in the development and the pathophysiology of several autoimmune and allergic diseases. Thus, considering that maximum residue levels (MRLs) of PQ set by FAO and WHO for certain food and animal feed crops range between 0.005 and 10.0 mg/kg, our findings stress the importance of applying strict regulation on the use of PQ as an herbicide.