Zebrafish research is a successful alternative model to rodents, which have been commonly used in medical research for years.
This tiny tropical fish, also known as Danio Rerio, is commonly seen in aquariums and is a remarkable vertebrate that has made a significant difference to medical research over the last 20 years.
What is Danio Rerio (Zebrafish)?
The Zebrafish originates in South Asia and has become a popular alternative model in medical research due to its similarity to the human genome.
Danio rerio is named the Zebrafish due to its prominent 5 stripes along the length of its body. However, Zebrafish embryos are transparent, making them ideal for experimental viewing and monitoring.
How is Danio Rerio Similar to Humans?
The Zebrafish shares 70% of its genes with the human body. It has two eyes, a brain, pancreas, spinal cord, intestines, liver, kidneys and a heart.
It is a suitable model for medical research as it has more than 84% of the genes that cause genetic disease in humans. This means it can be used to study how a disease affects humans and how various compounds can be used to fight those diseases.
Of particular note is the similarity of Danio Rerio’s heart to the human heart, making it highly suitable for the study of heart disease. The Zebrafish heart can regenerate, making it a useful model to study how a human heart repairs with medication after being damaged.
The Benefits of Danio Rerio in Medical Research
In addition to being extremely similar to the human genetic composition, Zebrafish have several other advantages for use in medical research.
- Fast reproduction: Zebrafish can breed approximately every 2-3 days and each time can produce up to 300 embryos (compared to mice which on average product between 5 and 10 litters per year)
- External fertilization: making it easy to work on the embryos
- Fast maturity: most of the main organs have formed in 24 hours and the Zebrafish is considered an adult at 3 months
- Transparent: for visualization of embryo development
- Cost-effective: both in terms of care and husbandry
- Regeneration: of the heart, eyes, tail and cells
- Highly sequenced: approximately 14,000 mutations created
Cost is a major factor in the choice of Zebrafish for research as drug development is an increasingly expensive field. The pressure on pharmaceutical companies to discover and safely market new medications to treat and prevent human disease is immense. Yet the cost can run into billions, so any cost savings are a benefit.
Another major benefit is time. On average it takes between 10-15 years from initial development to regulatory approval to bring a new drug to market. Any reduction in this time is a clear advantage towards the fight against human disease.
Danio Rerio also complies with the 3Rs principle (Reduce, Refine, Replace), which sets out the framework for the ethical use of animals in research.
How Is Danio Rerio Used for Research?
As mentioned above, because they are transparent, Zebrafish embryos are ideal for studying gene function and vertebrate development. Scientists use fluorescent proteins to view the behavior of cells and tissues in the model. The development of the vital organs can be monitored and studied to observe how they react to various strains of a disease.
As an in vivo model Zebrafish are used to study:
- Genetics
- Cell biology
- Toxicology
- Embryology
Zebrafish are not only used to study human disease research but are also used in other forms of research, such as cosmetics, agrochemicals or ecotoxicity, making them a versatile organism in the research sphere.
What Human Diseases Have Been Modeled in Zebrafish?
Heart disease is the leading cause of death in the world, with 55.4 million deaths in 2019 (World Health Organization). The Zebrafish plays a crucial role in the attempt to reduce heart disease due to its heart being similar to a human heart.
Other diseases studied in Zebrafish include:
These are only some of the diseases modeled in the Zebrafish. There is much more scope for other diseases to be studied using this species.
Danio Rerio is a major contributor to medical science and as research methods develop is likely to become even more significant in the quest to find cures and treatments for human diseases.
