Effect of Aroclor 1248 and Two Pure PCB Congeners upon the Membrane Fluidity of Rat Renal Tubular Cell Cultures

Abstract

The influence of different polychlorinated biphenyls (PCBs) upon dynamic properties of membranes from rat renal tubular cell cultures has been investigated. Studies have been realized with Aroclor 1248 (a commercial PCB mixture with 48% chlorine by weight), and two pure PCB congeners: 3,3′,4,4′-tetrachlorobyphenyl (a coplanar compound) and 2,2′,4,4′,5,5′-hexachlorobiphenyl (anortho-substituted nonplanar congener). Changes in the membrane fluidity were measured by the fluorescence polarization technique using the probe diphenylhexatriene. The treatment of cells with Aroclor 1248 increased membrane fluidity in a dose-dependent manner. Even though rat renal tubular cell cultures accumulated only a low amount of PCBs when cells were incubated in presence of the toxicant, that small quantity was enough to modify the membrane fluidity. Interestingly, a significant increase of membrane fluidity was found in presence of 2,2′,4,4′,5,5′-hexachlorobiphenyl, but no significant differences were detected in the presence of 3,3′,4,4′-tetrachlorobiphenyl. This means that changes in the membrane fluidity induced by the different PCB congeners are related to the coplanarity or lack of coplanarity of the toxic compounds.