STUDY ON THE INTERACTION OF Se AND ERYTHROCYTE MEMBRANE——EFFECT OF Se ON THE Na, K-ATPase ACTIVITY AND FLUIDITY OF ERYTHROCYTE MEMBRANES

The content of binding-Se in erythrocyte membrane may affect its structure and function. Decrease in So content will lead to a lower activity of Na, K-ATPase and lipid fluidity in ghosts, and a marked increase in Na, K-ATPase activity as well as lipid fluidity of erythrocyte membrane was observed by supplementation of low concentration of Na_2SeO_3 (0.03—0.3 ppm Se), in vitro. This effect was obvious only when the ghosts wore incubated with Se at 0—4°C for at least half an hour prior to assay.     

硒与红细胞膜的研究——Ⅰ.硒对红细胞膜Na,K-ATP酶活性和流动性的影响

人红细胞膜结合硒含量能够影响膜的结构与功能。结合硒含量减少会导致Na,K-ATP酶活性和膜脂流动性的降低。加入微量Na_2SeO_3(0.03—0.3ppm Se)能使Na,K-ATP酶活性和流动性显著增加。人红细胞膜必须与硒经半小时以上预处理才能显示出明显的效应。     

STUDY ON THE INTERACTION OF Se AND ERYTHROCYTE MEMBRANE——PROTECTIVE EFFECT OF Se ON THE ERYTHROCYTE MEMBRANES

During the ageing of erythrocyte membrane, the spectrin content, Na, K-ATPase activity as well as the lipid fluidity are obviously decreased. However, supplementation of a trace amount of Na_2SeO_3 in the medium could prevent the dissociation of spectrin from membrane and delay the changes of Na, K-ATPase activity and lipid fluidity. The effectiveness is proportional to Se concentration within the range of 0.1—1.0 ppm.Similar effect of supplementation of Se on the intact erythrocytes during ageing has been also observed.The protective action of Se on biomembranes is generally interpreted in terms of the activity of Se-containing glutathione peroxidase (GSHPx). However, GSHPx mainly distributes in the cytoplasma of erythrocytes, therefore it seems that the protective action of supplemented Se on the isolated erythrocyte membrane might not be related to the activity of GSHPx.     

硒与红细胞膜的研究——Ⅱ.硒对红细胞膜的保护作用

人红细胞膜老化(4℃,1—3周)过程中,收缩蛋白(spectrin)合量减少,Na,K-ATP酶活性和流动性都有明显降低。如果在老化介质中加入微量Na_2SeO_3(0.1—1.0ppm Se)可防止收缩蛋白从膜上脱落并延缓Na,K-ATP酶活性和膜流动性的变化。在0.1—1.0ppm Se范围内,加入硒量愈多,效应也愈明显。当完整红细胞老化时,外加硒对膜也有相似的保护作用。硒对膜的保护作用一般用含硒的谷胱甘肽过氧化物酶(GSHPx)的活性来解释,但该酶主要分布在红细胞细胞质内,因此人红细胞膜结合硒对膜具有明显保护作用似乎很难归结于GSHPx的作用。     

大骨节病患儿红细胞膜骨架的变化

本文对大骨节病患儿红细胞膜骨架稳定性及红细胞ATP含量进行测定,结果:1.膜骨架蛋白主要组分血影收缩蛋白(Spectrin)与膜的结合程度下降,2.Spectrin本身的聚合状态有变化,3.~(31)P-NMR测试结果表明,大骨节病患者红细胞膜化学位移各向异性增加,提示膜骨架蛋白与膜脂静电作用增加,磷脂‘头部’运动自由度减少,4.大骨节病患儿红细胞膜内含能源物质ATP明显减少,5.大骨节病患儿红细胞硒含量明显低于对照。本文还对硒与红细胞膜骨架,低硒与大骨节病发病机理进行了讨论。