Long-term exposures to ethion and endotoxin cause lung inflammation and induce genotoxicity in mice

Geetika Verma, Chandra Sekhar Mukhopadhyay, Ramneek Verma, Baljit Singh, R. S. Sethi

Ethion, an organophosphorus pesticide, is used worldwide and has potential for toxicity and inflammation. There are very limited data on the pulmonary and genotoxic effects of ethion especially when the exposure is combined with lipopolysaccharide. Therefore, we used a mouse model to test the hypothesis that prolonged exposure to ethion alone or in conjunction with lipopolysaccharide (LPS) will cause lung inflammation and genotoxicity in a mouse model. Swiss albino (n = 30) were divided into a control (n = 10) and two treatment groups (n = 10; each group). The treatment groups were orally administered ethion (4 or 2 mg/kg/animal/day; n = 10 each) dissolved in corn oil for 90 days. After 90 days of exposure, five animals from each of the groups were challenged with 80 μg Escherichia coli lipopolysaccharide (LPS) intranasally and the remaining five animals with normal saline solution via the same route. Ethion at both dosages induced lung inflammation as indicated by increased (p < 0.05) perivascular and peribronchial accumulation of inflammatory cells along with thickening of the alveolar septal wall. Ethion at 4 mg/kg altered (p < 0.05) the mRNA and protein expression of TLR-9 and IL-1β in the lungs and induced genotoxicity in blood cells as determined by single cell gel electrophoresis (Comet assay). Further, both dosages of ethion in combination with E. coli LPS caused genotoxicity and increased (p < 0.05) pulmonary expression of TLR-4, TLR-9 and IL-1β. The data taken together suggest ethion induces lung inflammation and interaction between ethion and LPS increases genotoxicity in blood cells.