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Animal research

07 - 11 - 2016

Why is the zebrafish such a good research model ?

Since the late 1990s, this small fish has attracted researchers and invaded their laboratories. And for a reason. This animal model, that doesn’t look anything special, has actually many assets. 

Why is the zebrafish such a good research model ?

 

November 4, new research on zebrafish made headlines and sparked new hopes. Scientists from Duke University, USA, discovered how the zebrafish ( or Danio rerio) are able to a certain extent “fix” their spinal cords. They managed to isolate a growth factor (called ctgfa) which acts as a bridge between neurons in order to repair injured areas of the spinal cord. In humans, this growth factor also exists, yet we are unable to repair any damage to our spinal cord. The study of this mechanism in zebrafish could help understand what is different in humans, and perhaps ultimately develop a drug. 

 

 

A fish that has a lot to teach us

 

If the zebrafish and humans can seem very different at first sight, this hasn’t stopped the fish from becoming a star in laboratories in just a few years. According to the statistics of the National Institute of Health, published last August, the number of fellowships allocated to the research on zebrafish has increased by almost 60% from 2008 to 2015. And this enthusiasm is still on the rise. There are of course ‘obvious’ advantages to using this little fish in research: it takes little space, it is cheap, easy and fast to breed, becomes mature in less than three months… but not only ! 

Produced in large numbers, zebrafish embryos develop outside of the female. Moreover, this fish is transparent in the early staged of its development, and can be made transparent at later stages via genetic manipulation. No need for surgery or intrusive procedures to see what goes on inside it. It is therefore possible to monitor and analyse the trajectory and fate of stem cells, viruses or even toxins, whereas it is unthinkable to do so in humans or mice. A whole bunch of fundamental of behavioural mechanisms are studied in zebrafish, and at the scale of the organism, the cell and even the molecular scale. 

To date, zebrafish are also well studied in fundamental research, especially in developmental biology, and in applied research. Neurosciences, immunology, oncology, toxicology and even genetics, these are only a few of the research areas that can use this model. Between 70 and 85% of human genes have an equivalent in zebrafish. Manny human diseases can therefore be studied in zebrafish. 

 

 

Finally, it should be noted that the regulation is also more flexible for this model. The larvae of zebrafish are considered as animals only from the moment they feed, that is to say, after 6 days of existence. This leaves an interesting window for scientists to study them without restriction. 

It should however be noted, that if this model is more and more used, it does not replace the research in rodents downstream. Indeed, zebrafish are not close enough to us to enable a transposition of the results obtained from fish directly to mammals and humans. 

 

Hélène Bour

 

For more information :

https://irp.nih.gov/blog/post/2016/08/why-use-zebrafish-to-study-human-diseases

https://efor.fr/pages/organisms/?id=36

https://www.sciencedaily.com/releases/2016/11/161103142321.htm

http://www.ipubli.inserm.fr/bitstream/handle/10608/4405/MS_1991_6_553.pdf?sequence=1