An alternative method to the traditional NASA hindlimb suspension model in mice

Abstract

Animal models are used to induce atrophy and to evaluate interventions. The Morey‐Holton hindlimb unloading (HU) method is widely accepted.PURPOSEEvaluate an alternative to the Morey‐Holton HU technique in mice.METHODSForty adult female mice were HU for 14 days with (n=24) or without (n=16) recovery. Ambulatory controls (n=49) were used for comparison. A thin stainless steel wire was passed through the intervertebral disc spaces between the 5th and 7th sacral vertebrae and shaped into a ring from which the mice were suspended. The vertebral location was selected to appropriately balance the animal's body weight but not interfere with defecation. Success of this novel hindlimb unloading technique was assessed by percent body weight lost during suspension, soleus atrophy and adrenal mass.RESULTSBody mass of the mice prior to HU (24.8 ± 3.8g) was not significantly different immediately after HU (23.8 ± 2.8g), or after 3 days recovery (24.7 ± 2.5g. Soleus mass declined (−35.6%) with HU (p<0.001. Adrenal gland weights did not significantlyCONCLUSIONThe new method allows for ease of tail examination during suspension; decreases the likelihood of cyanotic, inflamed, and/or necrotic tails frequently observed with tail‐taping; and of mice chewing the traction tape (and becoming unsuspended). This tail‐ring method also ensures rapid recovery following HU. Support HD058834, MU Life Sciences Fellowship.