Comparative effects of technical toxaphene, 2,5-dichloro-3-biphenylol and octabromodiphenylether on cell viability, [Ca2+]i levels and membrane fluidity in mouse thymocytes.
Flow cytometric studies of mouse thymocytes show that technical toxaphene (10-20 ppm) and 2,5-dichloro-3-biphenylol (PCB 9-OH) (5-10 ppm) kill cells and cause an increase in intracellular calcium concentration, [Ca2+]i, whereas commercial octabromodiphenylether (OBDE) has no effect. The cell death is not a result of the rise of [Ca2+]i, since the divalent cation ionophore, ionomycin, causes a large elevation in [Ca2+]i without cell death. We have studied effects of these compounds on membrane fluorescence polarization, a measure of membrane fluidity, using 1,6-diphenyl-1,3,5-hexatriene (DPH). We find that toxaphene causes a decrease in membrane fluidity in the concentration range associated with cell death, whereas PCB 9-OH causes an increase in fluidity and OBDE has no effect. These observations suggest that alterations of membrane fluidity of thymocytes, whether it be an increase or decrease, can cause cytotoxicity.
Sandal
Suleyman
S
Department of Physiology, Faculty of Medicine, Firat University, 23119 Elazig, Turkey.
Yilmaz
Bayram
B
Chen
Chang-Hwei
CH
Carpenter
David O
DO
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D005411:Flame Retardants / Q000633:toxicity*; D006842:Hydrocarbons, Brominated / Q000633:toxicity*; D008560:Membrane Fluidity / Q000187:drug effects*; D051379:Mice; D008813:Mice, Inbred ICR; D010647:Phenyl Ethers / Q000633:toxicity*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D014112:Toxaphene / Q000633:toxicity*
D005411:Flame Retardants; D006842:Hydrocarbons, Brominated; D010647:Phenyl Ethers; D014112:Toxaphene; D011078:Polychlorinated Biphenyls; D002118:Calcium