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Updated: May 11, 2026
In vivo Imaging of Optic Nerve Fiber Integrity by Contrast-Enhanced MRI in Mice
Published on: July 22, 2014
Novel ascorbic acid-resistive nitroxide in a lipid emulsion: an efficient brain imaging contrast agent for MRI of
Miho C Emoto1, Ken-Ichi Yamada, Mayumi Yamato
1Center for Medical Education, Sapporo Medical University, Sapporo, Hokkaido 060-8556, Japan.
Abstract:
Nitroxides have recently been used as redox-sensitive contrast agents for both MRI and EPR imaging. However, the rapid in vivo reduction in paramagnetism of nitroxides due to reductants such as ascorbic acid (AsA) has limited their use as contrast agents. This study developed a formulation of a newly synthesized AsA-resistive nitroxide (2,2,6,6-tetraethylpiperidine-4-one-1-oxyl (TEEPONE)) with a lipid emulsion system and examined the in vivo stability of TEEPONE by magnetic resonance imaging (MRI). MRI of mouse heads after administration of TEEPONE clearly indicated that TEEPONE has a remarkable in vivo stability and is a blood-brain barrier (BBB) permeable nitroxide. MRI also showed that TEEPONE is preferentially localized in the mouse brain. The distribution of TEEPONE in the mouse head can be controlled by the lipid content in the emulsion system used to solubilize TEEPONE.
