A new process for turning the bodies of lab animals transparent may one day not only decrease the number of creatures killed in the name of science, but also revolutionize how researchers study disease.
Called "ultimate 3D imaging of solvent-cleared organs" (uDISCO), the process starts with mice or rats that are genetically engineered to have proteins that glow green under a laser scanning microscope. Once deceased, the specimens are repeatedly flushed with a special solution that removes water and fats from tissues and generates a transparency of 85-95 percent with everything from bones to organs.
"The clarity is quite complete," Ali Erturk, a neurobiologist at Ludwig-Maximilians-Universität München, told Business Insider. "You see a yellowish hue, but that is coming from residual tissue."
The technique also shrinks the rodents' bodies by as much as 65 percent, making it must easier to fit entire specimens under a laser scanning microscope for study. Once engaged, the green proteins light up under the microscope, generating an unprecedented map of a rodent's neural network from head to tail.
Collated digitally, this information effectively allows researchers to "fly" through the neural pathways of a rodent. In the future, the researchers hope to utilize uDISCO to map the human brain, offering new insights into neurological diseases like Alzheimer's and Parkinson's.
"These methods may in the future offer highly detailed three dimensional analysis of human post-mortem organs or ... surgically removed tumors, with a speed that was previously unimaginable," Ertuk added.
Because the process also generates a digital atlas of specimens, it's likely that it will reduce the number of animals killed each year for study.
"Even if it's 5% or 10% or 20%, it would mean hundreds of thousands of animals worldwide every year," Ertuk said.
The research team's findings are published in the latest issue of Nature Methods. You can see a virtual fly-through of a mouse's central nervous system courtesy of the uDISCO process below.