Lagerberg J W, VanSteveninck J, Dubbelman T M
Department of Molecular Cell Biology, Leiden University, The Netherlands.
Photochem Photobiol. 1998 Jun;67(6):729-33.
Illumination of erythrocytes in the presence of merocyanine 540 (MC540) resulted in changed binding characteristics of MC540, i.e. a red shift in the emission maximum of bound dye with an increase in the relative fluorescence quantum yield. Aluminum phthalocyanine tetrasulfonate-mediated photodynamic treatment, before addition of MC540, resulted in a comparable change in the MC540-binding characteristics with, in addition, an increase in the concentration of MC540 in the membrane. Both photodynamic treatments induce depolarization of the red cell membrane, with a dose dependency comparable to that of changed MC540 binding. Also depolarization, induced by incubation of the cells with A23187 in the presence of Ca2+ in high [K+] buffer, resulted in similar changes in the MC540 binding characteristics. These results indicate a relation between photodynamically induced membrane depolarization and changed MC540-binding characteristics. Hyperpolarization induced by incubation with A23187 in low [K+] buffer resulted in decreased binding of MC540. In accordance, the MC540-mediated photodamage to red cells decreased upon hyperpolarization of the cells. The results indicate that the binding of MC540 to erythrocytes is strongly dependent on the membrane potential and that hyperpolarization of the membrane could be a possible protection mechanism for erythrocytes against MC540-mediated photodynamic damage.
在部花青540（MC540）存在的情况下对红细胞进行光照，会导致MC540的结合特性发生变化，即结合染料发射最大值出现红移，同时相对荧光量子产率增加。在添加MC540之前，用四磺基铝酞菁介导的光动力处理会导致MC540结合特性发生类似变化，此外，膜中MC540的浓度也会增加。两种光动力处理均会导致红细胞膜去极化，其剂量依赖性与MC540结合变化的剂量依赖性相当。同样，在高[K⁺]缓冲液中Ca²⁺存在的情况下，用A23187孵育细胞诱导的去极化也会导致MC540结合特性发生类似变化。这些结果表明光动力诱导的膜去极化与MC540结合特性变化之间存在关联。在低[K⁺]缓冲液中用A23187孵育诱导的超极化会导致MC540结合减少。相应地，细胞超极化后，MC540介导的对红细胞的光损伤会降低。结果表明，MC540与红细胞的结合强烈依赖于膜电位，并且膜的超极化可能是红细胞对抗MC540介导的光动力损伤的一种可能保护机制。
