Muscle Alterations Persist Beyond Weight Restoration In A Rodent Model Of Anorexia Nervosa

Anorexia Nervosa (AN) results in weight loss that contributes to excessive morbidity and mortality. We recently demonstrated AN also results in significant muscle loss; however, there is little data on how AN negatively impacts muscle health after weight restoration. PURPOSE: Investigate muscle health in a rodent model of AN following long-term weight restoration. METHODS: Female Sprague-Dawley rats (n = 11, 8 weeks old) underwent restricted feeding for 30 days to simulate the restrictive eating state of AN. During restricted feeding, rats were given ~50% of their ad libitum food consumption. After restricted feeding, AN rats were allowed ad libitum access to food for an additional 30 days. A separate group of female Sprague-Dawley rats (n = 11, 8 weeks old) had access to food ad libitum throughout the entire protocol (CON). RESULTS: Immediately after the food restriction period, AN animals had ~30% lower bodyweight compared to CON animals. After reintroduction of food, AN rats attained bodyweights comparable to CON within ~12 days. Despite this, even after 30 days of refeeding, AN animals still had ~11% lower front paw grip strength and ~ 15% lower rear paw grip strength compared to CON. Moreover, AN animals had lower muscle mass compared to CON: ~9% less for gastrocnemius, ~13% less for soleus, ~9% less for tibialis anterior, and ~ 11% less for plantaris muscles. CONCLUSIONS: Deleterious muscle alterations due to restricted feeding persist even after bodyweight restoration. These findings suggest that individuals with AN may also develop previously unrecognized functional limitations resulting in reduced quality of life. NIH Grant K12HD051959