Transcellular signalling pathways and TNF-alpha release involved in formation of reactive oxygen species in rat alveolar macrophages exposed to tert-butylcyclohexane.
In the present work, the effects of aliphatic ( n-nonane and n-decane), alicyclic (1,2,4-trimethylcyclohexane and tert-butylcyclohexane, t-BCH) and aromatic (trimethylbenzene and tert-butylbenzene) hydrocarbon solvents on formation of reactive oxygen species (ROS) and the proinflammatory cytokine TNF-alpha in rat alveolar macrophages (AM) have been investigated. Formation of ROS was assessed by monitoring oxidation of 2',7'-dichlorofluorescin to 2',7'-dichlorofluorescein (DCF), and the proinflammatory cytokine tumour necrosis factor alpha (TNF-alpha) was detected using an enzyme-linked immunosorbent assay. DCF fluorescence was elevated in a concentration-dependent manner by the alicyclic hydrocarbons. The involvement of transcellular signalling pathways in the production of ROS by t-BCH, the most active compound, was elucidated by use of specific inhibitors. Preincubation of the AM with the mitogen-activated protein kinase (ERK 1/2) inhibitor U0126, the protein kinase C inhibitor bisindolylmaleimide, the superoxide dismutase inhibitor diethyldithiocarbamate, and the iron ion chelating agent deferoxamine reduced the DCF fluorescence significantly. t-BCH gave an increase in TNF-alpha release. Further, nitric oxide production measured by a modified Griess method, and intracellular calcium concentration measured by fura-2, were increased in the rat AM after exposure to t-BCH.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D003510:Cyclohexanes / Q000737:chemistry / Q000633:toxicity*; D006801:Humans; D006840:Hydrocarbons, Alicyclic / Q000737:chemistry / Q000633:toxicity; D006841:Hydrocarbons, Aromatic / Q000737:chemistry / Q000633:toxicity; D066298:In Vitro Techniques; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D016676:Macrophages, Alveolar / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D051381:Rats; D011921:Rats, Inbred WKY; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D012997:Solvents / Q000737:chemistry / Q000633:toxicity*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases
D003510:Cyclohexanes; D006840:Hydrocarbons, Alicyclic; D006841:Hydrocarbons, Aromatic; D017382:Reactive Oxygen Species; D012997:Solvents; D014409:Tumor Necrosis Factor-alpha; C054362:tert-butylcyclohexane; D009569:Nitric Oxide; C482128:MAP2K2 protein, human; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases; D002118:Calcium