Shorter2 project protocol

Heart size in a Diversity Outbred (DO) mouse population   (2018)

Shorter JR, Jensen BC




Project protocol - Contents

Workflow and sampling

Step
Procedure
Equipment
Data collected
1
Administer diets -
-
2 Weigh and euthanize mice
Scales Body weight
3 Harvest heart and weigh Scales Heart weight
4 Harvest femur and measure Digital calipers Femur length

Equipment and supplies

  • Balance
  • Digital calipers

Reagents and solutions

  • 10% formalin

Procedure: Diet administration

  1. Two cohorts of DO mice were used: Generation 10 (G10) and G11. G10 mice were administered the control diet upon arrival at the test facility at 4 wks of age and maintained on that diet until 12-15 wks of age when they were euthanized. G11 mice were split into two groups and administered the control diet at 4 wks of age for 2 wks and then maintained on their respective experimental diets until 24-25 wks of age (18-19 wks on the experimental diet) when they were euthanized.
  2. The high-fat, cholic acid (HFC) diet contained 20% fat, 1.25% cholesterol, and 0.5% cholic acid to induce atherosclerotic lesions.
  3. The low-fat, high-protein (LFHP) diet contained 5% fat and 20.3% protein. This diet is not atherogenic.

Procedure: Heart weight and femur length

  1. Mice are weighed then euthanized by CO2 asphyxiation followed by cervical dislocation.
  2. The heart is dissected from the chest cavity; atria and all adherent tissue are carefully excised prior to weighing the ventricles.
  3. Right hind legs are removed and fixed in 10% formalin; afterward, the femur is dissected and measured two independent times to 0.01 mm using digital calipers.

Data collected by investigator

  • Body weight
  • Heart weight
  • Heart weight adjusted to body weight
  • Femur length
  • Heart weight adjusted to femur length