Assessment of high fat diet-induced fatty liver in medaka.

Fatty liver, which has been continuously growing in the number of patients, is the most common liver disease. For detailed analysis, a useful model of fatty liver is desired and fish is considered as a candidate of the models. We assessed direct observation of the liver, which is the most conventional method for the non-invasive analysis of the progression in fatty liver. By using transparent medaka, changes in fat deposition in the liver were able to be observed. An analysis of the assessment of the progression in fatty liver using Ultrasound showed a significant increase in echo intensity, which indicates that this is a useful examination method. In addition, we clarified a metabolite profile of the liver in medaka fed a high fat diet (HFD), which had not been shown in detail. This medaka model allowing non-invasive and repetitive assessment is a useful model for the analysis of diseases causing fatty liver in which changes in detailed metabolites are identified.