Japan scientists make see-through mice

Researchers at the RIKEN Quantitative Biology Center in Japan, together with collaborators from the University of Tokyo, have developed a method that combines tissue decolorization 

and light-sheet fluorescent microscopy to take extremely detailed images of the interior of individual organs and even entire organisms.

The work, published in Cell, opens new possibilities for understanding the way life works—the ultimate dream of systems biology—by allowing scientists to make tissues and whole organisms transparent and then image them at extremely precise, single-cell resolution.

To achieve this feat, the researchers, led by Hiroki Ueda, began with a method called CUBIC (Clear, Unobstructed Brain Imaging Cocktails and Computational Analysis), which they had previously used to image whole brains.

Though brain tissue is lipid-rich, and thus susceptible to many clearance methods, other parts of the body contain many molecular subunits known as chromophores, which absorb light.

One chromophore, heme, which forms part of hemoglobin, is present in most tissues of the body and blocks light. The group decided to focus on this issue and discovered, in a surprise finding, that the aminoalcohols included in the CUBIC reagent could elute the heme from the hemoglobin and by doing so make other organs dramatically more transparent.