There are several methods. The most common approach is to obtain the wet muscle mass. The disadvantage of this method is that it is cross-sectional (postmortem) and can give variable results depending of the dissection of the specific muscle. Care must also be taken for cross-sectional measures where male and female mice are used in the study, as male mice typically have greater muscle mass than females. The inclusion of cross-sectional muscle weights from age-matched male and female mice in a study can have a high biological variability that can obscure a significant drug effect.
We use computed tomography (CT) imaging coupled with robust automated image segmentation methods. This non-invasive approach allows for longitudinal measures in the same animal and accurate, reproducible measures of different muscles, thereby reducing variability and maximizing the potential to identify a potential therapeutic effect on muscle atrophy.