Sample preparation for high-resolution 3D confocal imaging of mouse skeletal tissue

• Published in: Nature protocols Vol. 10; no. 12; pp. 1904 - 1914
• Main Authors: Kusumbe, Anjali P, Ramasamy, Saravana K, Starsichova, Andrea, Adams, Ralf H
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2015; Nature Publishing Group
• Subjects: 14/63; 631/136/818; 631/1647/245/2221; 631/1647/328/1978; 631/443/63; Analytical Chemistry; Animals; Biological Techniques; Bone and Bones - cytology; Bone and Bones - ultrastructure; Computational Biology/Bioinformatics; Confocal microscopy; Diagnostic specimens; Histocytological Preparation Techniques - methods; Imaging, Three-Dimensional - methods; Life Sciences; Mice; Mice, Inbred C57BL; Microarrays; Microscopy, Confocal - methods; Organic Chemistry; Physiological aspects; protocol; Sample preparation; Skeleton; Spatial distribution; Tissues
• ISSN: 1754-2189; 1750-2799
• DOI: 10.1038/nprot.2015.125

This protocol describes how to prepare thick sections of mouse skeletal tissue for high-resolution 3D confocal imaging. Samples prepared in this way retain both fluorescence activity and antigenicity, allowing simultaneous imaging of multiple markers. High-resolution confocal imaging is a vital tool for analyzing the 3D architecture and detailed spatial distribution of cells in situ . However, imaging of skeletal tissue has remained technically challenging because of its calcified nature. Here we describe a protocol that allows high-resolution imaging of skeletal tissue with preservation of cellular morphology and tissue architecture. The procedure involves tissue fixation, decalcification and cryosectioning of the mouse skeletal tissue to generate thick sections. The thick sections generated by this procedure are not only compatible with the analysis of genetically expressed fluorescent proteins but they also preserve antigenicity, thus enabling diverse combinations of antibody labeling. Further, this procedure also permits other fluorescence techniques such as TUNEL and ethynyl deoxyuridine (EdU) incorporation assays. Images resulting from the confocal imaging can be assessed qualitatively and quantitatively to analyze various parameters such as distribution and interrelationships of cell types. The technique is straightforward and robust, highly reproducible and can be completed in ∼11 d.