三尖杉酯碱对大鼠心肌肌质网膜脂过氧化及膜脂分子运动的影响

Effects of harringtonine on peroxidation and dynamic microstructure of membrane lipids of myocardial sarcoplasmic reticulum in rat

目的：研究三尖杉酯碱（Ｈａｒ）对膜脂过氧化及膜脂运动的影响．方法：膜脂过氧化用硫代巴比妥酸法测定，其含量用ＭＡＡ表示；用纳秒荧光偏振技术研究膜脂过氧化对膜脂分子运动的影响．结果：Ｈａｒ１０ｍｇ·Ｌ－１可使ＭＡＡ由１７±０８增加至５４±５１μｍｏｌ／ｇ蛋白质；随过氧化脂质含量的增加，膜脂双层的微粘度增加，磷脂分子摆动角减小（ｒ＝－０８５６５，Ｐ＜００１），Ｃａ２＋转运ＡＴＰ酶活性降低（ｒ＝－０８７１４，Ｐ＜００１）；ＤＰＨ的荧光强度减弱，荧光寿命缩短．结论：Ｈａｒ引起肌浆网膜脂过氧化，因而影响膜脂双层的运动和膜蛋白的功能．

AIM: To study the effects of harringtonine (Har) on peroxidation and dynamic microstructure of membrane lipids and the relationship between them. METHODS: A nanosecond time-resolved fluorometer was used to study the effects of Har on dynamic microstructure of sarcoplasmic reticulum (SR) vesicles from rat myocardium. The amount of lipid peroxide was measured with thiobarbituric acid test and expressed as amount of malonaldehydic acid (MAA). RESULTS: Har 10 mg . L(-1) increased MAA. in SR (from 1.7 +/- 0.8 to 5.4 +/- 5.1 mu mol/g protein, P < 0.05). With the increase of MAA, the membrane viscosity also increased, while the wobbling angle of the phospholipid molecules decreased (r = -0.8565, P < 0.01), the Ca2+-ATPase activity decreased (r = -0.8714, P < 0.01), the fluorescence intensity and the fluorescence life time decreased. CONCLUSION: Har may cause the peroxidation of membrane lipids in SR, which affected the mobility of the phospholipid bilayers and the function of membrane proteins.