Salgia R, Becker J H, Sayeed M M
Dept. of Medicine, Johns Hopkins Univ. School of Medicine, Baltimore, MD 21205.
Mol Cell Biochem. 1993 Apr 21;121(2):143-8. doi: 10.1007/BF00925973.
Steady-state fluorescence anisotropy measurements of the fluorescent hydrocarbon probe 1,6-diphenyl-1,3,4-hexatriene (DPH) were carried out in isolated hepatocytes of saline control and Salmonella enteritidis endotoxin (20 mg/kg) injected rats. Statistically significant differences were observed in the fluorescent anisotropy (rs) and membrane microviscosity (eta) values of control (rs = 0.107 +/- 0.004 (SEM), eta = 0.98 +/- 0.08, n +/- 6) versus endotoxin injected rat hepatocytes (rs = 0.134 +/- 0.005, eta = 1.43 +/- 0.08, n = 6, p < 0.001) at 37 degrees C. Fluidity was similarly lower in the isolated plasma membrane preparations from endotoxin-injected rat livers relative to control livers. When endotoxin-injected rats were treated with the calcium channel-blocker diltiazem, the anisotropy and microviscosity values were comparable to those obtained from control rats (rs = 0.152 +/- 0.003, eta = 1.00 +/- 0.003, n = 6). These measurements were made in animals five hours after endotoxin had been injected, and thus represent the in vivo effects of bacterial endotoxins. Temperature scan studies of DPH from 5-40 degrees C revealed that the membrane fluidity of endotoxin-injected rat hepatocytes was significantly lower than control hepatocytes at all temperatures investigated. The data suggest that endotoxin alters the membrane fluidity of hepatocytes, and that calcium-channel blockers can prevent the alteration. Our previous studies have shown that calcium channel blocker prevented endotoxin induced alterations in hepatic cellular regulation of Ca2+. Thus, cellular calcium homeostasis may be important in the maintenance of membrane fluidity and other membrane-associated transport functions.
使用荧光烃探针1,6 - 二苯基 - 1,3,4 - 己三烯（DPH）对生理盐水对照大鼠和注射肠炎沙门氏菌内毒素（20 mg/kg）的大鼠的离体肝细胞进行稳态荧光各向异性测量。在37℃时，观察到对照大鼠（rs = 0.107±0.004（SEM），η = 0.98±0.08，n = 6）与注射内毒素的大鼠肝细胞（rs = 0.134±0.005，η = 1.43±0.08，n = 6，p < 0.001）的荧光各向异性（rs）和膜微粘度（η）值存在统计学显著差异。相对于对照肝脏，注射内毒素的大鼠肝脏分离的质膜制剂中的流动性同样较低。当给注射内毒素的大鼠用钙通道阻滞剂地尔硫卓治疗时，各向异性和微粘度值与对照大鼠相当（rs = 0.152±0.003，η = 1.00±0.003，n = 6）。这些测量是在内毒素注射后5小时对动物进行的，因此代表了细菌内毒素的体内效应。对DPH在5 - 40℃进行温度扫描研究表明，在所有研究温度下，注射内毒素的大鼠肝细胞的膜流动性均显著低于对照肝细胞。数据表明内毒素改变了肝细胞的膜流动性，并且钙通道阻滞剂可以防止这种改变。我们之前的研究表明钙通道阻滞剂可防止内毒素诱导的肝细胞Ca2 +调节改变。因此，细胞钙稳态可能在维持膜流动性和其他与膜相关的转运功能中起重要作用。
