Plasma membrane perturbation induced by tributyltin chloride on density-separated trout erythrocytes

Abstract

By using a discontinuous Percoll gradient in the 45–65% range it is possible to separate nucleated Salmo irideus erythrocytes in three different density fractions that are related to aging of the cell. The stability to lysis of the erythrocytes obtained from the three layers was examined in the presence and in the absence of Bu3SnCl4 (TBTC). The rate of hemolysis in the absence of the organotin was nearly the same for the three erythrocyte fractions. The addition of TBTC to the suspension increased the hemolysis but the effect depended on the density of the fraction. The change in the hemolysis rate was in the order bottom (B) > middle (M) > top (T). The effect of TBTC on 1,6-diphenyl-1,3,5-hexatriene (DPH) steady-state fluorescence anisotropy was measured in liposomes formed by the lipids extracted from the different fractions. Compared with the controls, the DPH anisotropy decrease in the presence of TBTC. Steady-state fluorescence of 2-dimethylamino-6-laurylnaphthalene (Laurdan) was measured to evaluate membrane polarity. The presence of TBTC on the same liposomes decreased the generalized polarization (GP340) in the top and middle fractions while it did not change in the bottom fraction. Copyright © 1999 John Wiley & Sons, Ltd.