Optimization of the optical transparency of bones by PACT-based passive tissue clearing

Exp Mol Med. 2023 Oct;55(10):2190-2204. doi: 10.1038/s12276-023-01089-8. Epub 2023 Oct 2.

Abstract

Recent developments in tissue clearing methods such as the passive clearing technique (PACT) have allowed three-dimensional analysis of biological structures in whole, intact tissues, thereby providing a greater understanding of spatial relationships and biological circuits. Nonetheless, the issues that remain in maintaining structural integrity and preventing tissue expansion/shrinkage with rapid clearing still inhibit the wide application of these techniques in hard bone tissues, such as femurs and tibias. Here, we present an optimized PACT-based bone-clearing method, Bone-mPACT+, that protects biological structures. Bone-mPACT+ and four different decalcifying procedures were tested for their ability to improve bone tissue clearing efficiency without sacrificing optical transparency; they rendered nearly all types of bone tissues transparent. Both mouse and rat bones were nearly transparent after the clearing process. We also present a further modification, the Bone-mPACT+ Advance protocol, which is specifically optimized for processing the largest and hardest rat bones for easy clearing and imaging using established tissue clearing methods.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone and Bones* / diagnostic imaging
  • Imaging, Three-Dimensional* / methods
  • Mice
  • Rats