Nature takes a closer look the way different physical systems connection – the way the brain, the muscles, the blood vessels relate to one another – by gazing into the hardened, transparent bodies of invisible mice:
The approach, called vDISCO, has already revealed surprising structural connections between organs, including hints about the extent to which brain injuries affect the immune system and nerves in other parts of the body. That could lead to better treatments for traumatic brain injury or stroke.
By making the dead mice rigid and see-through, it can preserve their bodies for years, down to the structure of individual cells, says Ali Ertürk, a neuroscientist at Ludwig Maximilian University of Munich in Germany, who led the team that developed vDISCO.
The process begins by soaking a mouse’s body in organic solvents to strip it of fats and pigments. This preserves the structure of the mouse’s cells, even as the animal shrinks by up to 60%1.
To explore the transparent mice, Ertürk’s team developed a way to home in on specific cell types, such as neurons or cancer cells. The scientists turned to ‘nanobodies’: antibodies that are found only in llamas, camels and alpacas, and are one-tenth the size of antibody molecules in other species.
Similar to their larger cousins, nanobodies can be engineered to stick to specific proteins that are found only in one type of cell — while carrying fluorescent green markers that labels the chosen cells. And because nanobodies are so small, they can easily pass through tiny blood vessels and into organs.
When the researchers pumped these nanobodies into the circulatory systems of dead mice, which carried the molecules throughout the body, they could see individual cells glowing bright green under a microscope.
Labelling neurons showed that nerves in a mouse’s torso degraded after the animal suffered a traumatic brain injury, even though the nerve cells were far from the injury site. In another case, the scientists spotted immune cells that had rushed to the site of a spinal-cord injury days before a mouse died — and, unexpectedly, into surrounding muscle and lymphatic vessels.
Some really fascinating visuals at the link.