Sicchieri Letícia Bonfante, de Andrade Natal Rodrigo, Courrol Lilia Coronato
Center of Lasers and Applications, Institute of Energy and Nuclear Research, São Paulo University, São Paulo, Brazil.
Departments of Pathology, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
Int J Cardiovasc Imaging. 2016 Oct;32(10):1595-604. doi: 10.1007/s10554-016-0936-7. Epub 2016 Jul 13.
The objective of this study is to characterize arterial tissue with and without atherosclerosis by fluorescence lifetime imaging microscopy (FLIM) using Europium Chlortetracycline complex (EuCTc) as fluorescent marker. For this study, twelve rabbits were randomly divided into a control group (CG) and an experimental group (EG), where they were fed a normal and hypercholesterolemic diet, respectively, and were treated for 60 days. Cryosections of the aortic arch specimens were cut in a vertical plane, mounted on glass slides, and stained with Europium (Eu), Chlortetracycline (CTc), Europium Chlortetracycline (EuCTc), and Europium Chlortetracycline Magnesium (EuCTcMg) solutions. FLIM images were obtained with excitation at 405 nm. The average autofluorescence lifetime within plaque depositions was ~1.36 ns. Reduced plaque autofluorescence lifetimes of 0.23 and 0.31 ns were observed on incubation with EuCTc and EuCTcMg respectively. It was observed a quenching of collagen, cholesterol and TG emission spectra increasing EuCTc concentration. The drastic reduction in fluorescence lifetimes is due to a resonant energy transfer between collagen, triglycerides, cholesterol and europium complexes, quenching fluorescence.
本研究的目的是通过使用氯四环素铕络合物（EuCTc）作为荧光标记物的荧光寿命成像显微镜（FLIM）来表征有和没有动脉粥样硬化的动脉组织。在本研究中，将12只兔子随机分为对照组（CG）和实验组（EG），分别给予正常饮食和高胆固醇饮食，并治疗60天。将主动脉弓标本的冰冻切片在垂直平面上切割，安装在载玻片上，并用铕（Eu）、氯四环素（CTc）、氯四环素铕（EuCTc）和氯四环素铕镁（EuCTcMg）溶液染色。在405nm激发下获得FLIM图像。斑块沉积物内的平均自发荧光寿命约为1.36ns。分别用EuCTc和EuCTcMg孵育后，观察到斑块自发荧光寿命分别降低了0.23和0.31ns。随着EuCTc浓度增加，观察到胶原蛋白、胆固醇和TG发射光谱的猝灭。荧光寿命的急剧降低是由于胶原蛋白、甘油三酯、胆固醇和铕络合物之间的共振能量转移，从而猝灭荧光。
