Rat Analog Model of Partial Gravity (NASA)
Another important focus sought to develop a rat analog model of partial gravity to be able to study the impact of partial weight-bearing on the musculoskeletal system. Spaceflight research heavily relies on ground-based animal research to study different paradigms and assess both disuse and therapies in a longitudinal way. For the past 3 years, our team has focused on creating and validating a model able to mimic the Moon or Mars gravity, before mimicking a short space mission to Mars.
Figure 1: Drawings illustrating the rat partial weight-bearing apparatus (A) and the hindlimb suspension using a pelvic harness (B). Adapted from Mortreux M. et al., J Appl Physiol 125: 175-182, 2018, and Mortreux M. et al., J Vis Exp 146, 59327.
Animals’ weight can be partially supported by the harness, leading to a decreased weight bearing on all limbs (A), or no weight-bearing on the hindlimbs (B). These models are now routinely used to mimic disuse in laboratory settings.
Recently, our team has started to test nutraceutical therapies, hoping to preserve muscle health on Mars. Using Resveratrol, we presented the first potential non-invasive countermeasure to help sustain muscle health en route to Mars.
Our team has extended this work to better understand how the rest of the organism reacts to partial weight-bearing, and is currently investigating cardiovascular and stress response, as well as developing this model using females. Electrical impedance myography (EIM), a key technique of the Rutkove laboratory, is also used to assess muscle quality in this model.
In 2019, with the help of additional funding from NASA, we will go further and investigate concrete paradigms that will apply to astronauts in the near future. We will continue investigating the gravity as a continuum and help characterize and reduce muscle disuse.