title: Scalable and DiI-compatible optical clearance of the mammalian brain.
abstract: Efficient optical clearance is fundamental for whole brain imaging. In particular, clearance of the brain without membrane damage is required for the imaging of lipophilic tracer-labeled neural tracts. Relying on an ascending gradient of fructose solutions, SeeDB can achieve sufficient transparency of the mouse brain while ensuring that the plasma membrane remains intact. However, it is challenging to extend this method to larger mammalian brains due to the extremely high viscosity of the saturated fructose solution. Here we report a SeeDB-derived optical clearing method, termed FRUIT, which utilizes a cocktail of fructose and urea. As demonstrated in the adult mouse brain, combination of these two highly water-soluble clearing agents exerts a synergistic effect on clearance. More importantly, the final FRUIT solution has low viscosity so as to produce transparency of the whole adult rabbit brain via arterial perfusion, which is impossible to achieve with a saturated fructose solution. In addition to good compatibility with enhanced yellow fluorescent protein, the cocktail also preserves the fluorescence of the lipophilic tracer DiI. This work provides a volume-independent optical clearing method which retains the advantages of SeeDB, particularly compatibility with lipophilic tracers.
authors.affiliation: Brainnetome Center, Institute of Automation, Chinese Academy of Sciences Beijing, China ; National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences Beijing, China ; Beijing Institute of Radiation Medicine Beijing, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Hou
authors.affiliation: Brainnetome Center, Institute of Automation, Chinese Academy of Sciences Beijing, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Brainnetome Center, Institute of Automation, Chinese Academy of Sciences Beijing, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, and PKU-IDG/McGovern Institute for Brain Research, School of Life Sciences, Peking University Beijing, China.
authors.forename: Mengping
authors.initials: M
authors.lastname: Wei
authors.affiliation: Beijing Institute of Radiation Medicine Beijing, China.
authors.forename: Zaifu
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Beijing Institute of Radiation Medicine Beijing, China.
authors.forename: Shaoxia
authors.initials: S
authors.lastname: Wang
authors.affiliation: Beijing Institute of Radiation Medicine Beijing, China.
authors.forename: Jiarui
authors.initials: J
authors.lastname: Wang
authors.affiliation: Brainnetome Center, Institute of Automation, Chinese Academy of Sciences Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Brainnetome Center, Institute of Automation, Chinese Academy of Sciences Beijing, China ; National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences Beijing, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.affiliation: Brainnetome Center, Institute of Automation, Chinese Academy of Sciences Beijing, China.
authors.forename: Lingzhong
authors.initials: L
authors.lastname: Fan
authors.affiliation: Beijing Institute of Radiation Medicine Beijing, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Neuroscience, Shanghai Institutes for Biological Sciences Shanghai, China.
authors.forename: Zilong
authors.initials: Z
authors.lastname: Qiu
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, and PKU-IDG/McGovern Institute for Brain Research, School of Life Sciences, Peking University Beijing, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Brainnetome Center, Institute of Automation, Chinese Academy of Sciences Beijing, China ; National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences Beijing, China ; Queensland Brain Institute, The University of Queensland Brisbane, QLD, Australia ; Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China ; CAS Center for Excellence in Brain Science, Institute of Automation, Chinese Academy of Sciences Beijing, China.
authors.forename: Tianzi
authors.initials: T
authors.lastname: Jiang
keywords: 3DISCO; CLARITY; CUBIC; SeeDB; Urea; optical tissue clearing; tract tracing; whole brain imaging