US researchers develop method the make mice transparent
Breakthrough opens way to map nervous system, and show how cancers spread
Associated Press in New York
Researchers have found a way to make see-through mice, but you will not find them scampering around your kitchen.
The transparent rodents are not alive and are for research only, to help scientists study fine details of anatomy.
Before they are treated with chemicals, the animals are killed and their skin removed. Researchers made their inner organs transparent, but not their bones.
The results look like a rodent-shaped block of gelatin with the organs held in place by connective tissue and a gel used in the procedure.
Mice are mainstays of biomedical research because much of their basic biology is similar to ours and they can be altered in ways that simulate human diseases.
Scientists have been able to make tissues transparent to some degree for a century, and in recent years several fresh methods have been developed.
Last year, for example, a technique that produced see-through mouse brains made headlines.
Such treatments reveal far more detail than X-rays or MRI examinations could deliver.
The latest work was the first to make an entire mouse transparent, experts said.
It should be useful for projects such as mapping the details of the nervous system or the spread of cancer within laboratory animals, said Viviana Gradinaru, of the California Institute of Technology, who was the senior author of a detailed paper describing the work. It was released on Thursday by the journal Cell.
It might also help doctors analyse biopsy samples from people, she said.
The see-through technique involves pumping chemicals through blood vessels, as well as other passages in the brain and spinal cord.
Some chemicals form a mesh to hold tissue in place, while others wash out the fats that make tissue block light.
It took about a week to create a transparent mouse, Gradinaru said.
The researchers also have made transparent rats, which took about two weeks, she said.
Scientists can use stains to highlight anatomical details such as the locations of active genes.