GMC18 project protocol

Bone mineral density, body composition, and X-ray analysis of 8 inbred founder strains of the Collaborative Cross   (2020)

German Mouse Clinic and Department of Infection Genetics, HZI
With: Hrabě de Angelis M, Fuchs H, Gailus-Durner V, Mayer-Kuckuk P, Hans W, Lengger C, Kollmus H, Schughart K

See also: GMC18 animal documentation


German Mouse Clinic: Phenotyping Pipeline

Dual Energy X-Ray Absorptiometry (DXA) and X-Ray: 17-18 wks of age

 

  • Project protocol - Contents

    Workflow and sampling

    Step
    Procedure
    Equipment
    Data collected
    1 Body size Balance, ruler Body weight and length
    2 Mice anesthetized - -
    3 Dual-energy X-ray Absorptiometry (DXA) DXA analyzer Body composition and bone mineral density
    4 X-Ray X-Ray machine Skeletal parameters

    Equipment and supplies

    • Balance: Ohaus (AV213C)
    • DXA analyzer: Norland Stratec (pDEXA Sabre)
    • X-Ray machine: Faxitron (MX20-DC-12 X-Ray scanner)
    • Software: iX-Pect (for Faxitron)

    Reagents and solutions

    • Ketamine
    • Xylazine
    • Cleaning solution

    Procedure: Dual Energy X-Ray Absorptiometry (DXA) and X-Ray

      1. DXA:
        1. Mice are anesthetized with ketamine-xylazine (i.p.) and monitored until they become unconscious.
        2. Mice are weighed and the length of the mouse is measured with a disinfected ruler (measure length starting from the nose at 0 cm to the beginning of the tail (accuracy within 0.1 cm)).
        3. The mouse is placed in the DXA analyzer (calibrated daily using phantoms from the manufacturer) and a snout scan is performed.
        4. The area of interest is optimized and a measure-scan performed (exposure dose is 300 µSv).
        5. Regions of interest are defined for data analysis (whole body excluding the head).
        6. The mouse may go directly to the X-Ray machine (below). If not, the mouse is removed (once the image has been captured) and is placed on a heated mat (37°C) in a clean cage and monitored closely until consciousness is regained.
        7. Raw data are transformed by accompanying software into bone and non-bone components, and fat and lean mass are determined.
      2. X-Ray:
        1. An anesthetized (ketamine-xylazine) mouse is mounted onto an X-Ray permeable plate; the tail is curved along the left side of the body (used to enable identification of the X-Ray as dorsal or ventral).
        2. The plate is inserted into the X-Ray machine.
        3. The machine is set to a voltage of 25 kV with an integration time of 40 ms.
        4. An image is taken using the iX-Pect software.
        5. The mouse is removed and placed on a heated mat (37°C), in a clean cage and monitored closely until consciousness is fully gained.

    Data collected by investigator

    • DXA
      • Body weight
      • Body length
      • Total tissue mass
      • Fat tissue mass
      • Lean tissue mass
      • Bone mineral density
      • Bone area
      • Bone mass
    • X-Ray *
      • Number of lumbar vertebrae

    * Many other X-Ray parameters are available in the Supplemental data file (see GMC18 Downloads)