Magnetic resonance microscopy of mouse embryos.

Abstract

The increased use of the mouse as a model for various aspects of ammalian biology has caused a renewed interest in developing strategies for examining and comparing normal and abnormal mouse embryonic development and anatomy. In this study, we have explored the use of magnetic resonance microscopy as a tool for these purposes. Techniques for the fixation, embedding, perfusion, and image acquisition of mouse embryos are described. The perfusion of bovine serum albumin-diethylenetriaminepentaacetic anhydridegadolinium as a contrast agent enhances images of the developing embryonic vasculature during critical stages of organogenesis and allows for comparisons when embryos have been treated with teratogens such as retinoic acid. The acquired three-dimensional data sets are available for archiving, distributing, and postacqulsition manipulations such as computer segmentation of anatomical structuresThe mouse has become the animal model of choice for studying mammalian embryonic development because of the experimental techniques that have developed around it and because of its long and detailed history as a genetic model. However, technologies for analysis of developmental anatomy and mutant structures have not kept pace with technologies involving the manipulation of the mouse germ line to produce these developmental phenotypes. The storage, interpretation, and dissemination of the large amounts of data on these abnormal phenotypes presents an important challenge. The wide acceptance of the mouse as a preferred animal model is complemented by the extensive collection and documentation of >1000 mutant loci of mice (1). Transgenic technology has become commonplace, allowing the transfer offoreign genes into the mouse germ line and has led to the growth of service laboratories producing many lines of transgenic mice for investigators. Additionally, the germ line of mice can be manipulated by targeting mutations into specific genes in embryonic stem cells, making it possible to study the immediate and ultimate functions of the specific genes (2). A vast body of in situ hybridization information concerning the three-dimensional expression patterns of genes in the mouse embryo is quickly developing as more genes are isolated and examined. Current formats for describing morphological abnormalities of embryonic gene expression are inadequate because they are two dimensional, whereas the information being generated is three and four dimensional. In addition, investigators creating abnormal mice do not always have adequate training to evaluate the morphological changes being studied. For these reasons, there is a growing need for a means by which multidimensional anatomy can be recorded and easily transmitted to many investigators.In this report, we describe how magnetic resonance (MR) microscopy can be used to acquire three-dimensional data sets of embryonic anatomy for study on personal computers, how the embryonic vasculature can be enhanced and examined, and how anatomical structures can be computersegmented from a...

Vascular phenotyping of brain tumors using magnetic resonance microscopy (μMRI)

“…As mMRI is nondestructive and preserves 3D tissue and blood vessel architecture, it has been used to characterize the mouse embryonic vasculature (Berrios-Otero et al, 2009;Smith et al, 1994). When combined with different kinds of MR contrasts such as diffusion-weighted (DW) MRI, mMRI can provide unique information on the brain tumor microenvironment.…”

The free fatty acid metabolome in cerebral ischemia following human mesenchymal stem cell transplantation in rats

“…Few studies have attempted to establish a system with which to monitor the therapeutic effects of stem cells in ischemic rats. For example, magnetic resonance imaging (MRI) has recently been used to monitor the therapeutic effects of stem cell transplantation in chronic ischemia in rats [9,10], and MRI provides high-resolution images, showing the fate and migration of transplanted stem cells. Transplantation of MSCs in stroke might elicit a multifaceted cascade of biochemical events both in brain and circulating plasma.…”

Embryonic Liver Morphology and Morphometry by Magnetic Resonance Microscopic Imaging

“…It is a noninvasive and nondestructive imaging method, and has been applied to analyze embryonic development in different animal models (Bone et al, 1986;Smith et al, 1992Smith et al, , 1994Smith et al, , 1996. MR imaging of embryos is highly advantageous (Effmann et al, 1988;Smith et al, 1992;Haishi et al, 2001), providing a resolution of 40 lm/pixel or better with long scan times.…”