$$\rightleftharpoonup{xx}$$
$$\longleftharp{xx}$$,
$$\longrightharp{xx}$$,
In recent years, zebrafish (Danio rerio) have emerged as a valuable model organism in various scientific fields, including genetics, developmental biology, and toxicology1,2,3. Zebrafish are small tropical freshwater fish native to the rivers of Southeast Asia4. They have become a popular model organism in biology due to their easy maintenance, small size, rapid reproductive cycle, and translucent embryos1. This allows for easy observation of their internal development, making them ideal for studying various biological processes in developmental biology. Zebrafish share genetic similarities with humans; approximately 70% of human genes have at least one zebrafish counterpart, making them an excellent model for studying genetic disorders and diseases in humans5,6. By manipulating specific genes in zebrafish, researchers can gain valuable insights into the function and behavior of genes, which can then be applied to human health research6, gene editing, and the creation of transgenic lines7,8.
Zebrafish scales regenerate after removal9,10 and can be cultured for one to three days with a basic (non-CO2) incubator while they are used for experiments11. The use of zebrafish scales is advantageous in basic laboratories as they can be removed from anesthetized fish without the need for euthanasia. Zebrafish scales are a component of the dermal skeleton, consisting primarily of two layers: the internal layer, which is thick and made of partially mineralized tissue formed by layers of collagen fibrils, and the external layer, which is highly mineralized and contains a network of interwoven collagen fibrils12,13 (Figure 1A-C). These morphological and cellular features of the scale are easily observed under a standard compound microscope. These characteristics make zebrafish scales a good model for studying cellular and molecular. For example, zebrafish scales have been used to study bone homeostasis, including bone cell activity11,12. They have also been used to understand tissue regeneration9,14,15, gene pathways and signaling14,16, metabolism17, microbiota studies18, etc. Zebrafish, similar to other teleosts, are also highly sensitive to environmental factors such as pollutants and toxins19,20,21,22. As such, fish scales are used to study exposures to toxins in fish populations. These characteristics make scales an excellent model for teaching students about the impacts of environmental factors on living organisms. Additionally, scales from transgenic zebrafish lines, such as Tg(osterix:mCherry) and Tg(runx2a:GFP), could add another level of complexity to student experiments.
In summary, by using zebrafish scales, researchers can design and conduct experiments to study various aspects of biology, from cellular mechanisms to environmental changes. Zebrafish are also a valuable resource in higher education since they can provide hands-on experiences in experimental design, data collection, and analysis. Zebrafish can also be utilized in advanced courses and research-focused programs to explore specific areas of interest. This article describes a protocol for using zebrafish scales in research and classroom learning environments.