The polychlorinated biphenyl mixture aroclor 1254 induces death of rat cerebellar granule cells: the involvement of the N-methyl-D-aspartate receptor and reactive oxygen species.
Polychlorinated biphenyls (PCBs) are widespread persistent environmental contaminants that display a complex spectrum of toxicological properties, including neurotoxicity. The present study investigates the effects of the PCB mixtures Aroclor 1242 (A1242) and Aroclor 1254 (A1254), and the PCB congeners 126 (3,3',4,4',5,-PeCB) and 153 (2,2',4,4',5,5'-HxCB) on formation of reactive oxygen species (ROS) and cell death in cultured rat cerebellar granule cells. The increase of ROS and induction of cell death were assayed using the fluorescent probe 2,7-dichlorofluorescin diacetate (DCFH-DA) and the trypan blue exclusion assay, respectively. A1242 and A1254 and PCB 153 induced a concentration-dependent increase in cell death and ROS formation. A1254 was selected for mechanistic studies. When the cerebellar granule cells were exposed to 15 microM A1254 for 12 h, 95% of the cells died. Both PCB-mediated cell death and the increase of the ROS formation were inhibited by MK-801, demonstrating the importance of the N-methyl-D-aspartate receptor. Inhibitors of nitric oxide synthase and phospholipase A2 led to a significant reduction of the DCF fluorescence and cell death. The mitochondrial permeability transition pore blocker cyclosporin A and the antioxidant vitamin E also increased survival and reduced ROS formation. The results show a connection between cell death and free radical formation.
Mariussen
Espen
E
Norwegian Defence Research Establishment, Kjeller, Norway. espen.mariussen@nilu.no
Myhre
Oddvar
O
Reistad
Trine
T
Fonnum
Frode
F
D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects*; D020111:Chlorodiphenyl (54% Chlorine) / Q000633:toxicity*; D016572:Cyclosporine / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000187:drug effects; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D018696:Neuroprotective Agents / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D005231:Fatty Acids, Unsaturated; D018696:Neuroprotective Agents; D010726:Phosphodiesterase Inhibitors; D011810:Quinoxalines; D017382:Reactive Oxygen Species; D016194:Receptors, N-Methyl-D-Aspartate; D020111:Chlorodiphenyl (54% Chlorine); C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; D016291:Dizocilpine Maleate; D016572:Cyclosporine; C059778:7,7-dimethyl-5,8-eicosadienoic acid; D019331:NG-Nitroarginine Methyl Ester