Morpho-anatomical analysis of zebrafish scale melanocytes

The zebrafish ( Danio rerio ) is an excellent research model in biomedical sciences and other upcoming research areas. Despite the huge importance of an effective and high-throughput zebrafish aquaculture, little is known about morpho-anatomy of its scales and their embedded melanocytes. Here we have analysed the morpho-anatomical structure of the zebra fish scales and their melanocytes, along with their distribution, position and the variations in number and their physiological responsive states. It was found that the maximum number of melanocytes ~150-200 was present in the scales from the dorsal region of the zebrafish minimum being in the ventral region. These melanocytes had an average diameter, of 3.65±0.927 microns; corresponding to the intermediate state (neither aggregated nor dispersed) of the melanophore index. Other regions of the zebrafish, such as head, tail and ventral regions, had ~120-150, ~50-80, ~0-10 number of melanocytes in their scales respectively. Among the four regions of the zebrafish, the most uniform and intermediate state melanocytes were found in the scales of the dorsal region. Our analysis of zebrafish scales and physiological responsiveness of different region melanocytes opens new vistas for future use of these disguised type of smooth muscle cells.