Much to the enjoyment of mice everywhere, scientific researchers are increasingly using the zebrafish for research. They are a fresh water fish, often referred to as danios. They are pretty common in just about every major pet store around. They also serve a very important role in science and may someday help save your life.
The late Dr. George Streisinger is attributed with much of the pioneering work of using zebrafish in research. The University of Oregon has a wonder website dedicated to the zebrafish and its use in the classroom. There are some real advantages to using these fish in research. As opposed to mice, whose embryonic development takes 21 days, zebrafish are actually recognizable as tiny fish in 24 hours. The eggs and fry are transparent during development. This allows scientists an unobstructed view of cell development and other parts of the fish’s body. Pictured below, you can see how transparent they are when they are young.
Zebrafish were the subject of a study recently published by researchers at the Carnegie Institution for Science. Carnegie’s Steven Farber, James Walters and Jennifer Anderson uncovered some mysteries of how lipids, like cholesterol and fatty acids, are absorbed and converted to fat in the body. Several proteins act as transports for a lipid called cholesterol, which has been linked to many human diseases. One of these proteins is called NPC1L1. The process by which cholesterol binds to this protein has presented a mystery. However, using fluorescent lipids, Farber’s team was able to watch these lipids travel through the intestines of the juvenile zebrafish. Because of this research they were able to ascertain the following:
- The physiological processes regulating fatty acid absorption and cholesterol absorption are linked, as was first suggested by studies involving rats in the 1960s.
- A fatty acid called oleic acid can greatly increase the uptake of dietary cholesterol.
- The subcellular location of the human protein NPC1L1, suspected to regulate cholesterol absorption, is modulated by the presence of oleic acid. (Farber’s team inserted the human NPC1L1 protein, fused to a red fluorescent protein, into the zebrafish.)
- In the presence of an abundance of dietary triacyglycerides, absorbed fatty acids were rapidly stored as lipid droplets. In contrast, cholesterol was stored in special structures, called endosomes,which are distinct from lipid droplets in zebrafish intestines.
Learning how this process works may someday prove to be helpful in developing better medicines to treat cholesterol and possibly help people lose weight. This also helps researchers understand the process of how fat works in the body. As many are beginning to discover, obesity is an epidemic however, scientists are finding that the causes for obesity aren’t as easily explained as once thought. Hopefully with the help of these little fish we’ll soon better understand how to cure many of our ills, not to mention those of our animal friends.