In vivo imaging and quantification of regional adiposity in zebrafish

Adipose tissues (ATs) are lipid-rich structures that supply and sequester energy-dense lipid in response to the energy status of an organism. As such, ATs provide an organism energetic insurance during periods of adverse physiological burden. ATs are deposited in diverse anatomical locations, and excessive accumulation of particular regional ATs modulates disease risk. Therefore, a model system that facilitates the visualization and quantification of regional adiposity holds significant biomedical promise. The zebrafish (Danio rerio) has emerged as a new model system for AT research in which the entire complement of regional ATs can be imaged and quantified in live individuals. Here we present detailed methods for labeling adipocytes in live zebrafish using fluorescent lipophilic dyes, and for identifying and quantifying regional zebrafish ATs.