Oxidative stress resulting from exposure of a human salivary gland cells to paraoxon: an in vitro model for organophosphate oral exposure.
Organophosphate (OP) compounds are used as insecticides, acaricides, and chemical agents and share a common neurotoxic mechanism of action. The biochemical alterations leading to many of the deleterious effects have been studied in neuronal cell lines, however, non-neuronal toxic effects of OPs are far less well characterized in vitro, and specifically in cell lines representing oral routes of exposure. To address this void, the human salivary gland (HSG) cell line, representing likely interactions in the oral cavity, was exposed to the representative OP paraoxon (PX; O,O-diethyl-p-nitrophenoxy phosphate) over a range of concentrations (0.01-100 μM) and analyzed for cytotoxicity. PX induced cytotoxicity in HSG cells at most of the exposure concentrations as revealed by MTT assay, however, the release of LDH only occurred at the highest concentration of PX tested (100 μM) at 48 h. Slight increases in cellular ATP levels were measured in PX-exposed (10 μM) HSG cells at 24 h. Exposing HSG cells to 10 μM PX also led to an increase in DNA fragmentation prior to loss of cellular membrane integrity implicating reactive oxygen species (ROS) as a trigger of toxicity. The ROS genes gss, gstm2, gstt2 and sod2 were upregulated, and the presence of superoxide following 10 μM PX exposure was determined via dihydroethidium fluorescence studies further implicating PX-induced oxidative stress in HSG cells.
Department of Biomedical and Pharmaceutical Sciences, College of Health Professions and Biomedical Sciences, The University of Montana, Missoula, MT 59812, United States.
John M
JM
Prins
Department of Biomedical and Pharmaceutical Sciences, College of Health Professions and Biomedical Sciences, The University of Montana, Missoula, MT 59812, United States.
Chih-Kai
CK
Chao
Department of Biomedical and Pharmaceutical Sciences, College of Health Professions and Biomedical Sciences, The University of Montana, Missoula, MT 59812, United States.
Saskia M
SM
Jacobson
Department of Biomedical and Pharmaceutical Sciences, College of Health Professions and Biomedical Sciences, The University of Montana, Missoula, MT 59812, United States. Electronic address: chuck.thompson@mso.umt.edu.
Charles M
CM
Thompson
Department of Biomedical and Pharmaceutical Sciences, College of Health Professions and Biomedical Sciences, The University of Montana, Missoula, MT 59812, United States. Electronic address: katie.george@mso.umt.edu.
Kathleen M
KM
George
D000110:Acetylcholinesterase / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002800:Cholinesterase Inhibitors / Q000633:toxicity*; D053938:DNA Fragmentation; D004435:Eating; D005981:Glutathione Synthase / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D007306:Insecticides / Q000633:toxicity*; D018384:Oxidative Stress; D010261:Paraoxon / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012469:Salivary Glands / Q000166:cytology*; D013482:Superoxide Dismutase / Q000235:genetics; D000099156:Superoxide Dismutase 2
D000110:Acetylcholinesterase; D000255:Adenosine Triphosphate; D002800:Cholinesterase Inhibitors; D005981:Glutathione Synthase; D005982:Glutathione Transferase; D007306:Insecticides; D010261:Paraoxon; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2; C491107:GSTT2 protein, human; C412602:glutathione S-transferase Mu 2
DNA fragmentation; HSG cells; MTT; Organophosphate; Oxidative stress; Paraoxon