Oral and Craniofacial Sciences

Imaging and Loading



















Skeletal Imaging and In vitro-In vivo Mechanical Loading Core
Mark L. Johnson, Ph.D.
Carrie Zhao (colony management, genotyping, Piximus and Faxitron)
Dina Black (microCT)
Mark Dallas (in vivo loading)
Dr. Johnson (in vitro loading

This core operation supports a number of functions relating to the maintenance of transgenic and knockout mouse lines and the characterization of bone phenotypes of these mice.

Animal Breeding and Skeletal Phenotyping

  1. This core is responsible for the management of our animal breeding colony. Transgenic and knockout mouse lines deposited in the core by a team of collaborators are bred as needed to meet the demands of a large range of experimental studies. The core also provides outside investigators breeding pairs of mice for their studies upon completion of required MTAs.
  2. This core also performs genotyping of all lines of mice being bred in the facility.
  3. Skeletal Phenotyping is supported by this core at three levels; a) bone densitometry (Piximus), b) X-ray analysis (Faxitron) and c) microCT imaging (Scanco vivaCT40) of excised bones or live animal for high resolution 3D analysis of bone properties.

Genotyping analysis of mouse lines.


X-ray image of the mouse.


MicroCT analysis of mouse skull
(live animal imaging).


In vivo Mechanical Loading

Application of surface mesh to microCT image of loaded mouse forearm for Finite Element Analysis model construction.


This core operation was the ability to perform both forearm and tibia compression loading on mice and rats (Bose Enduratec 3200).

  1. 3-and 4-point bending testing of bone biomechanical properties.
  2. If requested by investigators (recommended) the core will perform load: strain analysis using strain gages applied under controlled load conditions (ex vivo) so that subsequent in vivo loading levels are used that generate equivalent strains across lines of mice (e.g. transgenic or knockout versus control lines).
  3. Digital image capture analysis methods are currently being integrated into the core operation as means of validating Finite Element Analysis (FEA) models to predict strain fields produced by in vivo loading.
  4. MicroCT based static load imaging is performed for FEA model validation.

In vitro Mechanical Loading

  1. This core operation includes both fluid flow shear stress (FlexCell Streamer Gold Unit) and stretch (FlexCell FX-4000 Strain Unit) and a 2-chamber transwell shear stress system for co-culture studies.

Full training and technical support is provided for all investigators and limited analysis capability is provided as a service function of these cores.