Demir Pinar, Akkas Sara B, Severcan Mete, Zorlu Faruk, Severcan Feride
Department of Biological Sciences, Middle East Technical University, Dumlupınar Bulvarı No. 1, 06800, Ankara, Turkey.
Appl Spectrosc. 2015 Jan;69(1):154-64. doi: 10.1366/13-07154.
Humans can be exposed to ionizing radiation, due to various reasons, whose structural effects on biological membranes are not well defined. The current study aims to understand the ionizing radiation-induced structural and functional alterations in biomolecules of brain membranes using Fourier transform infrared (FT-IR) spectroscopy using rat animal models. For this purpose, 1000 cGy of ionizing radiation was specifically directed to the head of Sprague Dawley rats. The rats were decapitated after 24 h. The results revealed that the lipid-to-protein ratio decreased and that irradiation caused lipid peroxidation and increases in the amounts of olefinic =CH, carbonyl, and methylene groups of lipids. In addition, ionizing radiation induced a decrease in membrane fluidity, disordering of membrane lipids, strengthening of the hydrogen bonding of the phosphate groups of lipid head-groups, and weakening in the hydrogen bonding of the interfacial carbonyl groups of lipids. Radiation further caused significant decrements in the α-helix and turns, and significant increments in the β-sheet and random coil contents in the protein structure. Hierarchical cluster analyses, performed in the whole region (3030-1000 cm(-1)), lipid (3030-2800 cm(-1)), and protein (1700-1600 cm(-1)) regions separately, successfully differentiated the control and irradiated groups of rat brain membranes and showed that proteins in the membranes are affected more than lipids from the damages induced with ionizing radiation. As a result, the current study showed that FT-IR spectroscopy can be used successfully as a novel method to monitor radiation-induced alterations on biological membranes.
由于各种原因，人类可能会暴露于电离辐射中，而电离辐射对生物膜的结构影响尚未明确界定。本研究旨在利用大鼠动物模型，通过傅里叶变换红外（FT-IR）光谱法了解电离辐射引起的脑膜生物分子结构和功能变化。为此，将1000 cGy的电离辐射专门照射到斯普拉格-道利大鼠的头部。24小时后将大鼠断头。结果显示，脂质与蛋白质的比例降低，辐射导致脂质过氧化，脂质的烯烃 =CH、羰基和亚甲基含量增加。此外，电离辐射导致膜流动性降低、膜脂质紊乱、脂质头部基团磷酸基团的氢键增强以及脂质界面羰基的氢键减弱。辐射还导致蛋白质结构中的α-螺旋和转角显著减少，β-折叠和无规卷曲含量显著增加。分别在整个区域（3030 - 1000 cm(-1)）、脂质区域（3030 - 2800 cm(-1)）和蛋白质区域（1700 - 1600 cm(-1)）进行的层次聚类分析成功区分了大鼠脑膜的对照组和辐照组，并表明膜中的蛋白质比脂质受电离辐射损伤的影响更大。因此，本研究表明FT-IR光谱法可成功用作监测辐射引起的生物膜变化的新方法。
