title: Improved application of the electrophoretic tissue clearing technology, CLARITY, to intact solid organs including brain, pancreas, liver, kidney, lung, and intestine.
abstract: BACKGROUND
  Mapping of tissue structure at the cellular, circuit, and organ-wide scale is important for understanding physiological and biological functions. A bio-electrochemical technique known as CLARITY used for three-dimensional anatomical and phenotypical mapping within transparent intact tissues has been recently developed. This method provided a major advance in understanding the structure-function relationships in circuits of the nervous system and organs by using whole-body clearing. Thus, in the present study, we aimed to improve the original CLARITY procedure and developed specific CLARITY protocols for various intact organs.
  
  
  RESULTS
  We determined the optimal conditions for reducing bubble formation, discoloration, and depositing of black particles on the surface of tissue, which allowed production of clearer organ images. We also determined the appropriate replacement cycles of clearing solution for each type of organ, and convincingly demonstrated that 250-280 mA is the ideal range of electrical current for tissue clearing. We then acquired each type of cleared organs including brain, pancreas, liver, lung, kidney, and intestine. Additionally, we determined the images of axon fibers of hippocampal region, the Purkinje layer of cerebellum, and vessels and cellular nuclei of pancreas.
  
  
  CONCLUSIONS
  CLARITY is an innovative biochemical technology for the structural and molecular analysis of various types of tissue. We developed improved CLARITY methods for clearing of the brain, pancreas, lung, intestine, liver, and kidney, and identified the appropriate experimental conditions for clearing of each specific tissue type. These optimized methods will be useful for the application of CLARITY to various types of organs.
authors.affiliation: Department of Anatomy, Keimyung University School of Medicine, 1095 Dalgubeoldae-Ro, Dalseo-Gu, Daegu, 704-701, South Korea. neuroana@dsmc.or.kr.
authors.forename: Hyunsu
authors.initials: H
authors.lastname: Lee
authors.affiliation: Department of Physiology, Keimyung University School of Medicine, 1095 Dalgubeoldae-Ro, Dalseo-Gu, Daegu, 704-701, South Korea. pjh1015@gmail.com.
authors.forename: Jae-Hyung
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Microbiology, Keimyung University School of Medicine, 1095 Dalgubeoldae-Ro, Dalseo-Gu, Daegu, 704-701, South Korea. micro@dsmc.or.kr.
authors.forename: Incheol
authors.initials: I
authors.lastname: Seo
authors.affiliation: Department of Physiology, Keimyung University School of Medicine, 1095 Dalgubeoldae-Ro, Dalseo-Gu, Daegu, 704-701, South Korea. sunhyun_park@hms.harvard.edu.|Department of Microbiology and Immunobiology, Harvard Medical School, Division of Neuroscience New England Primate Research Center, 1 Pine Hill Drive, Southborough, MA, 01772, USA. sunhyun_park@hms.harvard.edu.
authors.forename: Sun-Hyun
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Immunology, Keimyung University School of Medicine, 1095 Dalgubeoldae-Ro, Dalseo-Gu, Daegu, 704-701, South Korea. god98005@dsmc.or.kr.
authors.forename: Shin
authors.initials: S
authors.lastname: Kim
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology; D004586:Electrophoresis; D007422:Intestines / Q000166:cytology; D007668:Kidney / Q000166:cytology; D008099:Liver / Q000166:cytology; D008168:Lung / Q000166:cytology; D051379:Mice; D061848:Optical Imaging / Q000379:methods*; D009928:Organ Specificity; D010179:Pancreas / Q000098:blood supply / Q000166:cytology