Purpose: Our aim in this study was to apply three-dimensional MRI methods to analyze early postnatal morphological phenotypes in a Gbx2 conditional knockout (Gbx2-CKO) mouse that has variable midline deletions in the central cerebellum, reminiscent of many human cerebellar hypoplasia syndromes.
Methods: In vivo three-dimensional manganese-enhanced MRI at 100-µm isotropic resolution was used to visualize mouse brains between postnatal days 3 and 11, when cerebellum morphology undergoes dramatic changes. Deformation-based morphometry and volumetric analysis of manganese-enhanced MRI images were used to, respectively, detect and quantify morphological phenotypes in Gbx2-CKO mice. Ex vivo micro-MRI was performed after perfusion-fixation with supplemented gadolinium for higher resolution (50-µm) analysis.
Results: In vivo manganese-enhanced MRI and deformation-based morphometry correctly identified known cerebellar defects in Gbx2-CKO mice, and novel phenotypes were discovered in the deep cerebellar nuclei and the vestibulo-cerebellum, both validated using histology. Ex vivo micro-MRI revealed subtle phenotypes in both the vestibulo-cerebellum and the vestibulo-cochlear organ, providing an interesting example of complementary phenotypes in a sensory organ and its associated brain region.
Conclusion: These results show the potential of three-dimensional MRI for detecting and analyzing developmental defects in mouse models of neurodevelopmental diseases.
Keywords: brain development; cerebellum; gastrulation brain homeobox 2 gene (Gbx2); manganese-enhanced MRI (MEMRI); mid-hindbrain; vestibulo-cochlear organ.
Copyright © 2013 Wiley Periodicals, Inc.