Multimodal imaging for tumour characterization from micro‐ to macroscopic level using a newly developed dorsal chamber designed for long‐term follow‐up

Abstract

Optical imaging of living animals is a unique method of studying the dynamics of physiological and pathological processes at a subcellular level. One‐shot acquisitions at high resolution can be achieved on exteriorized organs before animal euthanasia. For longitudinal follow‐up, intravital imaging can be used and involves imaging windows implanted in cranial, thoracic or dorsal regions. Several imaging window models exist, but none have proven to be applicable for long‐term monitoring and most biological processes take place over several weeks. Moreover, none are compatible with multiple imaging modalities, meaning that different biological parameters cannot be assessed in an individual animal. We developed a new dorsal chamber that was well tolerated by mice (over several months) and allowed individual and collective cell tracking and behaviour analysis by optical imaging, ultrasound and magnetic resonance tomography. This new model broadens potential applications to areas requiring study of long‐term biological processes, as in cancer research.

Cord blood-endothelial colony forming cells are immunotolerated and participate at post-ischemic angiogenesis in an original dorsal chamber immunocompetent mouse model

“…Then, we used an original model of ischemia in mouse using a dorsal chamber to demonstrate that beyond their tolerance by the immune system of the recipient mouse, CB-ECFCs are able to form new vessels 26 days after transplantation. This new model was recently described in the literature to study the tumoral angiogenesis [33]. We adjusted this model to directly visualize angiogenesis after ischemia in a living mouse.…”

“…Nine-week-old male C57BL/6JRj mice were weighed before anesthesia by gas inhalation (1.5% isoflurane in 1.5-2 L/min air flow). The surgical procedure was previously described in details [33]. Briefly, each mouse received a subcutaneous injection of 100 μL of Lidocaïne® (21.33 mg/ mL) in the scapular region before skin incision.…”

Live‐imaging of revertant and therapeutically restored dystrophin in the DmdEGFP‐mdx mouse model for Duchenne muscular dystrophy

“…Our future goal is to develop live pharmacodynamics for dystrophin restoration therapies. For this, we are currently developing a transcutaneous window allowing repetitive live‐imaging of skeletal muscle for up to several weeks, similarly as co‐authors of this work recently developed for tumour imaging [20]. Such longitudinal observations are essential to determine dosages and dosage intervals for long‐term treatment protocols.…”

Fluorescence Microscopy—An Outline of Hardware, Biological Handling, and Fluorophore Considerations

“…Methods for imaging heart, kidneys, pancreas, and spleen are less developed and are at greater risk of artefacts that may result from inflammatory reactions. Long-term imaging of cellular processes requires installation of the optical windows adjacent to the organ of interest in a live anesthetised animal (reviewed in [ 131 , 132 , 133 ]), which permit unlimited microscope access to various abdominal organs [ 97 , 134 ], lungs [ 135 , 136 ], tumour-associated vasculature [ 137 ] and lymphatic vessels [ 138 ], spinal cord [ 139 ], and brain [ 140 ]. Although this technique allows visualisation of tissues/organs in their orthotopic location, implantation of the windows can lead to infections and motion artefacts.…”