High Resolution Episcopic Microscopy for Qualitative and Quantitative Data in Phenotyping Altered Embryos and Adult Mice Using the New “Histo3D” System

Olivia Wendling (1, 2) , Didier Hentsch (2) , Hugues Jacobs (1) , Nicolas Lemercier , Serge Taubert (2) , Fabien Pertuy (1) , Jean-Luc Vonesch (2) , Tania Sorg (1) , Michela Di Michele (3, 4) , Laurent Le Cam (3, 4) , Thomas Rosahl (5) , Ester Carballo-Jane (5) , Mindy Liu (5) , James Mu (5) , Manuel Mark (1, 2, 6) , Yann Herault (2, 1)

1 ICS - Institut Clinique de la Souris
2 IGBMC - Institut de Génétique et de Biologie Moléculaire et Cellulaire
3 IRCM - U1194 Inserm - UM - Institut de Recherche en Cancérologie de Montpellier
4 ICM - Institut régional de Cancérologie de Montpellier
5 Merck & Co. Inc - Merck Sharp and Dohme
6 HUS - Les Hôpitaux Universitaires de Strasbourg

3D imaging in animal models, during development or in adults, facilitates the identification of structural morphological changes that cannot be achieved with traditional 2D histological staining. Through the reconstruction of whole embryos or a region-of-interest, specific changes are better delimited and can be easily quantified. We focused here on high-resolution episcopic microscopy (HREM), and its potential for visualizing and quantifying the organ systems of normal and genetically altered embryos and adult organisms. Although the technique is based on episcopic images, these are of high resolution and are close to histological quality. The images reflect the tissue structure and densities revealed by histology, albeit in a grayscale color map. HREM technology permits researchers to take advantage of serial 2D aligned stacks of images to perform 3D reconstructions. Three-dimensional visualization allows for an appreciation of topology and morphology that is difficult to achieve with classical histological studies. The nature of the data lends itself to novel forms of computational analysis that permit the accurate quantitation and comparison of individual embryos in a manner that is impossible with histology. Here, we have developed a new HREM prototype consisting of the assembly of a Leica Biosystems Nanocut rotary microtome with optics and a camera. We describe some examples of applications in the prenatal and adult lifestage of the mouse to show the added value of HREM for phenotyping experimental cohorts to compare and quantify structure volumes. At prenatal stages, segmentations and 3D reconstructions allowed the quantification of neural tissue and ventricular system volumes of normal brains at E14.5 and E16.5 stages. 3D representations of normal cranial and peripheric nerves at E15.5 and of the normal urogenital system from stages E11.5 to E14.5 were also performed. We also present a methodology to quantify the volume of the atherosclerotic plaques of ApoEtm1Unc/tm1Unc mutant mice and illustrate a 3D reconstruction of knee ligaments in adult mice.

Mots clés: 3D imaging; quantification; high-resolution episcopic microscopy; microanatomy; phenotyping

Domaines: Biologie du développement; Zoologie des vertébrés; Imagerie

Olivia Wendling, Didier Hentsch, Hugues Jacobs, Nicolas Lemercier, Serge Taubert, et al.. High Resolution Episcopic Microscopy for Qualitative and Quantitative Data in Phenotyping Altered Embryos and Adult Mice Using the New “Histo3D” System. Biomedicines, 2021, 9 (7), pp.767. ⟨10.3390/biomedicines9070767⟩. ⟨hal-03433478⟩