The Research On The Biological Toxicity Induced By Organophosphate Pesticides And Protective Effects Of Hydrogen

Nowadays, organophosphate pesticides (OPs) are the most widely used syntheticchemical compounds, and the toxic effect induced by OPs has become a global issue.Acute OPs exposure causes obvious symptoms, which is easy to rescue. Long-timeexposure with very low doses is the main way to contract OPs for most people, whichcaused various damages, such as neural development delayed, decline in learning andmemory. Moreover, chronic OPs exposure was reported to be associated withtumorigenesis. In the past, hydrogen was considered as the physiological inert gas.With developing of research, hydrogen was determined as a new antioxidant whichselectively scavenger hydroxyl radicals (·OH). Until now, the protective effect andmechanism of hydrogen on OPs toxicity have not been reported. This study wasaimed to explore mechanism and protection of OPs toxicity. Our results showed thatOPs induced reactive oxygen species (ROS) accumulation, reactivated Epstein-Barr(EB) virus, damage brain and liver. Hydrogen inhibited EB reactivation, alleviatedbrain and hepatic damage via scavenger ROS production. Hydrogen can be used as asimple protective method for person who was exposed to OPs for long-time. At thesame time, this study has scientific significance on the mechanism of OPs toxicity andhydrogen effects.The main works of this research is as follow:1. Chlorpyrifos (CPF) reactivated EB virus and the inhibition of hydrogen: EBvirus infected more than90%of the world’s population, and its reactivation isassociated with various tumorgenesis. In this study, In this study, Raji cell line wasexposed to chlorpyrifos (CPF) which is one of OPs with low toxicity. Oxidative stressof Raji cells and EB virus immediately-early gene BZLF-1was detected. CPFexposure caused significantly ROS production and non-enzymatic antioxidant GSHlevel decrease. SOD and CAT activities were increased with low concentration of CPF,while decreased with high CPF concentration. These results showed that CPF inducedoxidative stress of Raji cells. Moreover, MDA level, a biomarker of lipid peroxidation,and DNA breakage were obviously increased after CPF exposure. BZLF-1wasup-regulation, suggesting that EB virus lytic cycle was reactivated. Hydrogenattenuated oxidative stress and EB virus reactivation. The damage of biologicalmolecule induced by OPs was ameliorated. All these results suggested that OPs andEB virus may have synergistic carcinogensis. Hydrogen inhibited EB virusreactivation and biological molecular damage induced by OPs at the stage of ROSproduction. Hydrogen has significance on daily protection of OPs exposure.2. CPF caused decrease in acetyl cholinesterase (AChE) activity and protectiveeffect of hydrogen. Healthy8weeks old Wistar rats were used in this study, and1/20LD50CPF was supplied via gavage daily for8weeks, and drinking hydrogen-richwater. CPF convert into CPO with catalyzing of CYP2B6, a hypotype of P450family.Paraoxon1convert CPO into3,5,6-trichloropyridine-2-phenol (TCP). CPO canirreversibly combine with AChE, t he inhibition of AChE by OPs causesaccumulation of acetycholine at cholinergic synapses, with over-stimulation ofmuscarinic and nicotinic receptors. Our results showed that CPF exposure caused significantly decrease35.5%and62.1%in AChE activates in serum and brain.Hydrogen alleviated AChE activity decrease, suggesting that the protective effect ofhydrogen may be not limited to scavenger OH. Hydrogen may directly impact onCPO. This research expands the field of hydrogen biology.3. CPF caused brain and hepatic damage and protective effect of hydrogen:sub-toxic CPF exposure induced oxidative stress in serum, brain and liver. In serum,MDA level was increased, SOD and CAT activities decreased. In brain and liver,MDA level and SOD activity were significantly increased. CAT activity wasincreased in brain while decreased in liver. Hippocampus neurons are associated withlearning and memory function. Pukenje cell layer are the neurons associated withmotion. CPF intoxication caused nuclear shrinking, losing in cytoplasma in CA1,CA3and Pukenje cell layer. This result showed that CPF exposure caused severedamage in neuron. In liver, edema was observed without necrosis and inflammation.TUNEL staining showed that neuron cells was apoptotic in brain, while there was noobvious apoptosis in liver. All these results suggest CPF intoxication caused moresevere damage in brain compared with liver. Hydrogen ameliorated oxidative stress,and protected neuron and hepatic cell from damage. Overexpression of MnSOD couldinhibite apoptosis. MnSOD gene expression was not significantly increased, andPON1was lack in brain, which made CPF exist as high toxic CPO. In liver, increasein MnSOD expression and PON1make liver lesser damage. Hydrogen showedprotective effect of these injuries.4. CPF causes liver oxidative stress related genes change, and the function ofhydrogen molecules. Oxidative stress signaling pathways including ROS metabolismrelated genes, oxidation resistance related gene, oxygen transport protein and otheroxidative stress related genes. PCR chip results showed CPF exposure regulatedFmo2, Sod2, Cygb, Ldha, Gpx, Nox4, Gclc, Gclm, Cat, etc. hydrogen amelioratedthese regulations to normal levels.In conclusion, OPs can lead to cells and organisms to produce reactive oxygenspecies, activation of EB virus, cause the brain and hepatic tissue damage. Molecularhydrogen can be block in stage of ROS production, inhibition of EB virus activation,relieve brain and hepatic damage. Hydrogen can be as as daily protection measuresfor people exposed with low-dose CPF in long-term.