Exploring, imaging and characterising models at different scales

Based in Jouy-en-Josas, the platform can be incorporated into a study conducted within the rodent or aquaculture facilities, or used independently for projects involving other species or samples compatible with its capabilities.

Approaches can be incorporated from project design onwards to link the animal model to the data generated: infection progression, host response, signal dynamics, tissue structure, behaviour or another phenotype of interest.

The platform combines multiscale imaging, sorting and analysis of complex biological objects, 3D histology, physiological and behavioural assessment, with a particular focus on longitudinal and non-invasive measurements where relevant.

In vivo imaging

In vivo imaging allows selected biological phenomena to be monitored longitudinally during a study.

IERP has an IVIS SpectrumBL (PerkinElmer), used mainly in rodent and fish models for bioluminescence approaches.

These approaches provide repeated, spatially resolved measurements without necessarily requiring sampling at every analysis time point.

The equipment is installed in an L2 laboratory and may, subject to feasibility and applicable rules, be used for animals requiring A1 or A2 containment.

Projects involving biological agents or GMOs are assessed during feasibility review before any experimental work is scheduled. The team can help the project lead identify biosafety constraints, define technical requirements and prepare information for regulatory scoping, while respecting the project’s scientific responsibilities.

→ Assess an in vivo imaging strategy

Microscopy and multiscale imaging

The platform explores biological structures at different scales, from organisms to cells.

Our capabilities include:

• fluorescence stereomicroscopy (MZ10F)
• confocal microscopy (Leica SP8 DM6000) and two-photon microscopy with a Coherent femtosecond laser and temperature-controlled chamber
• light-sheet imaging using the Benchtop mesoSPIM

→ Visit the mesoSPIM website

3D histology

Ex vivo tissue analysis can complement measurements made during the study.

The Benchtop mesoSPIM provides 3D light-sheet imaging of large cleared samples. It can map fluorescent signals at cellular resolution within complex biological volumes, at the scale of a whole organ or organism.

Expertise includes whole-mount immunohistochemistry, tissue clearing, 3D light-sheet imaging, reconstruction and image analysis.

Cytometry and analysis of complex organisms

The COPAS FP-1000 (Union Biometrica) provides high-throughput analysis and sorting of complex biological objects, particularly zebrafish larvae and organoids.

Depending on the project, the approach can combine optical density and fluorescence signal analysis to characterise biological objects. The data allow events and signal intensity to be quantified, distribution profiles to be characterised and objects of interest to be selected for subsequent steps. The system can also sort and dispense objects into multiwell plates for individual monitoring or additional analysis.

Behaviour and functional monitoring

Behavioural measurements can complement biological and imaging data.

In mice, established approaches include monitoring with EthoVision and, depending on the question, tests of activity, anxiety, memory or coordination, such as open field, object recognition, mazes, rotarod, beam walking or grip strength testing.

In zebrafish, video-tracking systems such as ZebraCube (for juveniles or adults) and ZebraBox (for larvae) can be used.

In fish, particularly trout, video monitoring and movement analysis approaches are also under development and can be incorporated into R&D projects or collaborations assessed on a case-by-case basis.

These approaches can contribute to functional characterisation and the development of refinement and welfare-monitoring methods.

Physiology and functional phenotyping

The platform also has plethysmography, FlexiVent and metabolic cage capabilities, used according to the model and scientific question. Micro-ultrasound can be provided with the CIMA platform, according to project-specific arrangements.

Imaging, behavioural monitoring and cytometry approaches can be incorporated into projects in contained environments when the equipment, model and biosafety rules permit.

Data analysis and method development

The platform also develops internal approaches for data processing and analysis, particularly for images and complex biological data.

This work can include image processing and analysis, multimodal or statistical analyses, and artificial intelligence approaches for automated detection, segmentation and quantification.

At this stage, this is an internal development area that can be used on a case-by-case basis through collaborations or R&D projects; it is not offered as a standard standalone service.

Selecting measurements to answer the scientific question

A technology is not used simply because it is available.

Measurement selection depends on:

• the scientific question
• the species and model
• the study stage
• the phenomenon to monitor
• containment constraints
• the required temporal or spatial resolution
• the expected data

The platform can be approached independently of the rodent and aquaculture facilities, including for projects involving other species or samples, or incorporated from the design stage of a study conducted at IERP.