Sadzuka Yasuyuki, Nakagawa Kouhei, Yoshioka Hisashi, Sonobe Takashi
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
Int J Pharm. 2008 May 22;356(1-2):300-5. doi: 10.1016/j.ijpharm.2008.01.019. Epub 2008 Jan 19.
It is known that reactive oxygen species (ROS) are connected with various diseases, and many studies have examined redox conditions in the body. However, there is a problem with stability of ROS and selectivity of detection probe. In this study, we aimed to stabilize the detection probe, and have tried to encapsulate the probe in polyethyleneglycol (PEG)-modified liposomes. Dichlorodihydrofluorescein (DCDHF) is oxidized to dichlorofluorescein (DCF), a highly fluorescent product, by ROS. We tried liposomalization of DCDHF probes by the Bangham method. However, it was found that DCDHF was oxidized during preparation and converted to DCF. In contrast, when we performed to encapsulate DCDHF in the liposome after the preparation of empty liposome, the stabilized DCDHF encapsulated liposome was successfully proposed by the addition of DCDHF solution by freeze-drying and re-hydration. Furthermore, the encapsulated efficacy of PEG-modified liposomes was higher than unmodified liposomes. This DCDHF liposome was examined for reactivity with hydroxyl radical and peroxynitrite as highly ROS. It was confirmed that DCDHF liposome had a protective effect on the hydroxyl radical, though an effect of the liposomalization of DCDHF was not shown on reactivity of the peroxynitrite. Therefore, it is likely that the liposomalization of DCDHF has selectivity for certain radical species. It is hoped that these results can be applied to novel and simple diagnostics for redox detection of conditions in the body.
众所周知，活性氧（ROS）与多种疾病相关，许多研究已对体内的氧化还原状态进行了检测。然而，ROS的稳定性和检测探针的选择性存在问题。在本研究中，我们旨在稳定检测探针，并尝试将探针封装在聚乙二醇（PEG）修饰的脂质体中。二氯二氢荧光素（DCDHF）被ROS氧化为高荧光产物二氯荧光素（DCF）。我们尝试通过Bangham方法将DCDHF探针脂质体化。然而，发现DCDHF在制备过程中被氧化并转化为DCF。相比之下，当我们在制备空脂质体后将DCDHF封装在脂质体中时，通过冷冻干燥和再水化加入DCDHF溶液成功制备了稳定的DCDHF封装脂质体。此外，PEG修饰脂质体的封装效率高于未修饰的脂质体。对这种DCDHF脂质体与作为高ROS的羟基自由基和过氧亚硝酸盐的反应性进行了检测。证实DCDHF脂质体对羟基自由基有保护作用，尽管DCDHF脂质体化对过氧亚硝酸盐的反应性未显示出影响。因此，DCDHF脂质体化可能对某些自由基具有选择性。希望这些结果能够应用于体内氧化还原状态检测的新型简单诊断方法。
