Transparisation

Several chemical tissue clearing techniques have recently emerged that make animal or human tissues optically transparent. These techniques are applied to whole organs or thick tissues by homogenizing the refractive indices within the tissue. Cleared organs and tissues can thus be observed in 3D up to 8 mm deep at high resolution, without the long and tedious steps required for serial sectioning. Tissue clearing techniques are therefore highly valuable for analyzing biological processes in normal or pathological organs, both in basic biology and medical sciences.

Technology

With support from the Occitanie region, the European Union (FEDER), and the University of Montpellier, RHEM has acquired an X-Clarity tissue clearing system (Logos BioSystems), which enables highly efficient and reproducible tissue delipidation without using highly toxic solvents or reagents. For example, this system can clear a brain in 5 hours instead of 5 to 7 days manually.

The system’s Active Clarity Technique (ACT) preserves fluorescent tags from genetic modifications (e.g., YGF, GFP, Tomato, etc.), is compatible with fluorescent transfection markers (e.g., Vybrant+) and intercalating agents (e.g., DAPI, To-Pro-3), and maintains tissue antigenicity (e.g., Olig1, GFAP, NF200KD, myosin 7A, etc.). Furthermore, tissue clearing enables the use of second- and third-harmonic generation techniques (SHG, THG) for visualizing structures such as collagen and elastin fibers. It also allows the use of autofluorescence to observe the complete tissue architecture (e.g., meninges, muscle fibers, blood vessels, etc.).

According to Lee et al. (2016) Scientific Reports 6, Article number: 18631 (2016)

RHEM offers support for 3D study projects using the X-Clarity automated system. This includes tissue clearing, optional decalcification, and—depending on user requests—immunofluorescence processing, microscopic observation, and 3D reconstruction (e.g. with Imaris) in partnership with the MRI imaging platform.

Contacts

Please contact Chantal Ripoll, who oversees this technology within RHEM-AdV, via our RHEM-AdV contact form.