In vivo PET imaging of zebrafish and its application for detecting metabolic changes in response to...

In vivo PET/CT imaging of zebrafish associates the advantages of this small vertebrate model to functional and less invasive image capture techniques. However, protocols and standardization of these techniques are still under expansion. Here we checked the fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) and fluorine-18 sodium fluoride (¹⁸F-NaF) temporal whole-body distribution in living, healthy adult zebrafish. Thereafter, ¹⁸F-FDG whole-body biodistribution was determined under inflammation induced by lipopolysaccharide injection. We show that anesthetized adult zebrafish had a whole-body distribution of ¹⁸F-FDG reached after 30 min of radiotracer delivery, while ¹⁸F-NaF took 150 min to reach clear bone uptake. Comparison of data expression as SUV_mean, SUV_max and Relative uptake, demonstrated that the Relative uptake proved to be the more suitable strategy for these conditions, since it was less variable and more aligned to the images acquired. Whole-body PET imaging with ¹⁸F-FDG was capable of detecting significant differences in tracer uptake in the encephalon area between control and LPS-injected animals, when expressed as Relative uptake. These findings suggested that ¹⁸F-FDG and ¹⁸F-NaF distribution and bioaccumulation analysis through PET/CT is feasible in a simple protocol performed in live adult zebrafish, with potential to be explored in several disease models.