Focus: GS-III Science and Technology
Science and research have always relied on using animals to understand various human diseases, and the primary reasons have been the genetic similarity between animals and humans (mice share 98% of DNA with us), and that we have developed tools to edit genes in various animals.
Animal model for a disease
An animal model for a particular disease should fulfil two criteria:
- It should be able to “catch” that infection (in case of infectious diseases).
- It should show the clinical outcomes and altered physiology that accompanies the disease.
- Mice, the most widely used “models” to understand human diseases, cannot be infected with SARS-CoV-2.
- Even the genetically altered mice that can be infected with SARS-CoV-2 develop only mild lung infection and do not show fever, while – apart from fever, sore throat, cough, pneumonia, COVID-19 infection in humans is also known to affect the heart, kidneys, intestine, and brain.
- Scientists are now creating miniature 3D organ-like-structures, called “organoids” that aim to replicate a human organ.
- These mini organs, created using stem cells, which have similar three-dimensional structure and cellular composition as human organs, and thus, are better reflective of human biology compared to animal models.
- Infection of mini-lungs with SARS-CoV-2 showed that virus triggers a massive immune response, similar to what has been observed clinically in humans.
- Despite their potential, many of these mini-organs currently do not have blood supply, resident microbes or immune cells.
- Also, it is difficult to understand the holistic response based on individual organs.
-Source: The Hindu