Protective effects of molecular hydrogen on hepatotoxicity induced by sub-chronic exposure to chlorpyrifos in rats

Chlorpyrifos (CPF) is a organophosphate insecticide widely used in agriculture with attendant adverse health outcomes. Chronic exposure to CPF induces oxidative stress and elicits harmful effects, including hepatic dysfunction. Molecular hydrogen has been identified as a novel antioxidant which could selectively scavenge hydroxyl radicals.

The aim of this study was to determine whether the intake of hydrogen-rich water (HRW) could protect rats from hepatotoxicity caused by sub-chronic exposure to CPF.

Rats were treated with hydrogen-rich water by oral intake for 8 weeks. Biochemical indicators of liver function, SOD and CAT activity, GSH and MDA levels were determined by the spectrophotometric method. Liver cell damage induced by CPF was evaluated by histopathological and electron microscopy analysis. PCR array analysis was performed to investigated the effects of molecular hydrogen on the regulation of oxidative stress related genes.

Both the hepatic function tests and histopathological analysis showed that the liver damage induced by CPF could be ameliorated by HRW intake. HRW intake also attenuated CPF induced oxidative stress, as evidenced by restored SOD activities and MDA levels. The results of PCR Array identified 12 oxidative stress-related genes differentially expressed after CPF exposure, 8 of chich, including the mitochondrial Sod2 gene, were significantly attenuated by HRW intake. The electron microscopy results indicated that the mitochondrial damage caused by CPF was alleviated after HRW treatment.

The results obtained suggest that HRW intake can protect rats from CPF induced hepatotoxicity, and the oxidative stress signaling and the mitochondrial pathway may be involved in the protection of molecular hydrogen.