JaxCC1 project protocol for procedure: grip strength

Multisystem phenotyping of 18 Collaborative Cross strains   (2018)

The Jackson Laboratory

See also: JaxCC1 animal documentation         All protocol docs for JaxCC1


See JAX Pipeline on the IMPC website for order of tasks for all mice tested

Project protocol: Grip strength test



Introduction

The grip strength test is used to measure the neuromuscular function as maximal muscle strength of forelimbs and combined forelimbs and hindlimbs. These are assessed by the grasping applied by the mouse on a grid that is connected to a sensor. Three trials are carried out in succession measuring forelimb strength only, followed by three successive trials measuring the combined forelimb/hindlimb grip strength. Values are normalized against mouse body weight.



Study design

  • Paradigm: Baseline study
  • Panel: Collaborative Cross
  • Number of strains: 18
  • Sex: Both
  • Age: 7-9 wks
  • Sample size: Seven mice per sex from at least two litters
  • Number of cohorts: 1



    Workflow

    Step Description Equipment Data collected
    1 Grip strength: forelimb measures (3 trials) Grip strength meter apparatus Forelimb strength

    2

    Grip strength: forelimb and hindlimb measures (3 trials) Grip strength meter apparatus Combined forelimb and hindlimb strength
    3 Weigh mice Balance Body weight


    Equipment, software and supplies

    • Grip strength meter: Columbus Instruments, Chatillon-Ametek Digital Force Gauge, DFE II
      • Grid size: 3 x 3" (HMGU plate)
    • Balance


    Reagents and solutions

    • 70% Ethanol

     

    Procedure

    1. Set up and use of grip strength meter:
      • Check that the connection of the sensor to the grid is firmly in place to prevent the grid from turning around.
      • Turn the sensor on and select T peak mode, which will enable a measurement of the maximal strength exerted by the mouse. Do not apply loads greater than the nominal capacity of the force sensor at the risk of permanently damaging the strength gauge.
      • Reset the display sensor to zero.
    2. Measuring grip strength force:
      • Remove a mouse from its home cage, gripping the base of the tail between the thumb and forefinger.
      • Forelimb measurement: Lower the mouse over the grid keeping the torso horizontal and allowing only its forepaws to attach to the grid before and measurements are taken. Gently pull the mouse back by its tail ensuring the mouse grips the top portion of the grid and the torso remains horizontal and record the maximal grip strength value of the mouse that is displayed on the screen. Repeat this procedure twice more to obtain 3 forelimb grip strength measurements.
      • Forelimb and hindlimb measurement: Lower the mouse over the grip keeping the torso parallel with the grid and allow both its forepaws and hindpaws to attach to the grid before any measurements are taken. Gently pull the mouse back by its tail ensuring the torso remains parallel with the grid and record the maximal grip strength value of the mouse that is displayed on the screen. Repeat this procedure twice more to obtain 3 forelimb-hindlimb grip strength measurements.
    3. Place the mouse on the balance and record the weight.
    4. Place mouse back in its home cage
    5. Clean the grid with ethanol and allow time to dry before next test.

       

      Data QC: Calibrate the grip strength meter annually in accordance with the equipment guidelines. Force meter calibration 4-8 months with use of hanging weight.

      Formulas and derivations: Mean of 3 trials = sum of increments divided by the number of increments; strength normalized against body weight = mean divided by body weight

       


      Measurements

      LIMS field name MPD variable name Description Units Series Primary measurement Series order MPD computed Calculation Method Data type
      Forelimb strength t1 front_paws_1 forelimb grip strength, trial 1 g Yes frontpaws_1 1     grip strength test Float

      Forelimb strength t2

      front_paws_2 forelimb grip strength, trial 2 g Yes frontpaws_1 2     grip strength test Float
      Forelimb strength t3 front_paws_3 forelimb grip strength, trial 3 g Yes frontpaws_1 3     grip strength test Float
      Forelimb grip strength measurement mean front_paws_mean forelimb grip strength, average g Yes front_paws_mean 1   sum of increments/number of increments grip strength test Float
      Forelimb grip strength normalized against body weight front_paws_adj forelimb grip strength, average normalized to bw g Yes front_paws_mean 2   sum of increments/number of increments/body weight grip strength test Float
      Fore/hindlimb strength t1 all_paws1 forelimb and hindlimb grip strength, trial 1 g Yes all_paws1 1     grip strength test Float
      Fore/hindlimb strength t2 all_paws2 forelimb and hindlimb grip strength, trial 2 g Yes all_paws1 2     grip strength test Float
      Fore/hindlimb strength t3 all paws3 forelimb and hindlimb grip strength, trial 3 g Yes all_paws1 3     grip strength test Float
      Forelimb and hindlimb grip strength measurement mean all_paws_mean forelimb and hindlimb grip strength average g Yes all_paws_mean 1   sum of increments/number of increments grip strength test Float
      Forelimb and hindlimb grip strength normalized against body weight all_paws_adj forelimb and hindlimb grip strength, average normalized to bw g Yes all_paws_mean 2   sum of increments/number of increments/body weight grip strength test Float
      Body weight bw body weight g           body weight Float