An imaging technique lets scientists peer through the skin of a whole mouse or rat to examine its organs after death. Ali Ertürk of the Ludwig Maximilians University of Munich in Germany and his colleagues created a technique called ultimate DISCO (uDISCO), which removes pigments and lipids from the tissues of dead animals using an organic solvent. This leaves the organs and skin intact but transparent, while preserving genetically encoded fluorescent proteins. The method revealed the nervous system of a mouse in stark detail. uDISCO also shrinks bodies by up to 65%, making it possible to image whole animals using light-sheet microscopy, which excels at imaging smaller samples. Nature Methods http://dx.

Analysis of entire transparent rodent bodies after clearing could provide holistic biological information in health and disease, but reliable imaging and quantification of fluorescent protein signals deep inside the tissues remained a challenge. Here, we developed vDISCO, a pressure driven, nanobody based whole-body immunolabeling technology to enhance the signal of fluorescent proteins by up to two orders of magnitude. This allowed us to image and quantify subcellular details through bones, skin and highly autofluorescent tissues of intact transparent mice. For the first time, we visualized whole-body neuronal projections in adult mice. We assessed CNS trauma effects in the whole-body and found degeneration of peripheral nerve terminals in the torso. Furthermore, vDISCO revealed short vascular connections between skull marrow and brain meninges, which were filled with immune cells upon stroke. Thus, our new approach enables unbiased comprehensive studies of the interactions between the nervous system and the rest of the body.

Highlights d CHAPS forms smaller micelles allowing full permeabilization of aged human organs d SHANEL enables centimeters deep molecular labeling and clearing of whole human organs d SHANEL renders intact adult human brain and kidney transparent d Deep learning and light-sheet microscopy with SHANEL allows human organ mapping

Highlights d DeepMACT is a deep learning-based pipeline for comprehensive analysis of metastases d DeepMACT identifies micrometastases and single cancer cells in full-body 3D scans d DeepMACT reveals the efficacy of antibody-drug targeting in the entire body d DeepMACT indicates that the tumor microenvironment affects drug targeting efficacy