Joshi K, Joshi P G, Joshi N B
Department of Biophysics, National Institute of Mental Health and Neuro Science, Bangalore, India.
Indian J Biochem Biophys. 1995 Aug;32(4):200-6.
Photodynamic action of hematoporphyrin derivative (HpD) on the plasma membrane of human glioblastoma U-87MG cells was investigated using lipid and protein specific fluorescent probes trimethylammonium-1,6-diphenyl 1,3,5-hexatriene (TMA-DPH) and N-(1-pyrene)-maleimide (PM) respectively. Steady state anisotropy, decay time and time dependent anisotropy of these probes in U-87MG cells were measured. Light irradiation caused an increase in the steady state anisotropy of TMA-DPH in cells treated with HpD; however, no change in decay time was observed. Time dependent anisotropy measurements were performed and the data were analyzed using wobbling in cone model. A decrease in the rotational relaxation time (phi) as well as the cone angle (theta(c)) and an increase in the order parameter (S) of TMA-DPH were observed on photosensitization of cells. A decrease in the order parameter (S) of TMA-DPH were observed on photosensitization of cells. A decrease in the steady rate anisotropy and the rotational relaxation time (phi) of PM and enhancement in the lipid peroxidation were also observed. Our results show that the photodynamic action of HpD increases the order in the lipid bilayer and the mobility of the proteins in the plasma membrane of cells.
分别使用脂质和蛋白质特异性荧光探针三甲基铵-1,6-二苯基-1,3,5-己三烯（TMA-DPH）和N-（1-芘基）-马来酰亚胺（PM），研究了血卟啉衍生物（HpD）对人胶质母细胞瘤U-87MG细胞的质膜的光动力作用。测量了这些探针在U-87MG细胞中的稳态各向异性、衰减时间和时间依赖性各向异性。光照导致用HpD处理的细胞中TMA-DPH的稳态各向异性增加；然而，未观察到衰减时间的变化。进行了时间依赖性各向异性测量，并使用锥体内摆动模型分析了数据。在细胞光致敏后，观察到TMA-DPH的旋转弛豫时间（φ）以及锥角（θc）减小，有序参数（S）增加。在细胞光致敏后，观察到TMA-DPH的有序参数（S）减小。还观察到PM的稳态速率各向异性和旋转弛豫时间（φ）减小，以及脂质过氧化增强。我们的结果表明，HpD的光动力作用增加了脂质双层的有序性和细胞膜中蛋白质的流动性。
