In vivo Magnetic Resonance Microscopy and Hypothermic Anaesthesia of a Disease Model in Medaka

• Published in: Scientific reports 2016-06, Vol.6 (1), p.27188-27188, Article 27188
• Main Authors: Ueno, Tomohiro, Suzuki, Hirokazu, Hiraishi, Masahiro, Amano, Hideaki, Fukuyama, Hidenao, Sugimoto, Naozo
• Format: Article
• Language: English
• Subjects: 59; 59/57; 631/1647/245/1628; 64; 692/308/1426; Animals; Body Size; Cryoanesthesia - methods; Diet, High-Fat; Disease Models, Animal; Disease Progression; Humanities and Social Sciences; Humans; Liver - diagnostic imaging; Liver - metabolism; Magnetic Resonance Imaging - instrumentation; Magnetic Resonance Imaging - methods; multidisciplinary; Non-alcoholic Fatty Liver Disease - chemically induced; Non-alcoholic Fatty Liver Disease - diagnostic imaging; Oryzias; Science; Triglycerides - metabolism
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep27188

In medical and pharmacological research, various human disease models in small fish, such as medaka ( Oryzias latipes ), have been created. To investigate these disease models noninvasively, magnetic resonance imaging (MRI) is suitable because these small fish are no longer transparent as adults. However, their small body size requires a high spatial resolution and a water pool should be avoided to maximize the strength of MRI. We developed in vivo magnetic resonance microscopy (MR microscopy) without a water pool by combining hypothermic anaesthesia and a 14.1 T MR microscope. Using in vivo MR microscopy, we noninvasively evaluated the hepatic steatosis level of a non-alcoholic fatty liver disease model in medaka and followed the individual disease progression. The steatosis level was quantified by the MRI-estimated proton density fat-fraction (MRI-PDFF), which estimates the triglyceride fat concentration in liver tissue and is recognized as an imaging biomarker. The MRI-PDFF results agreed with a histological analysis. Moreover, we optimized the hypothermic anaesthesia procedure to obtain a recovery proportion of 1 in the experiment involving MR microscopy. Recovered medaka could not be distinguished from naïve medaka after the experiment. Therefore, the in vivo MR microscopy will expand the possibilities of a human disease model in fish.