Brain Matter Alterations during Simulated Anorexia Nervosa and Following Weight Recovery in Rats

Anorexia Nervosa (AN) is a psychiatric eating disorder that causes serious health consequences due to nutrient deprivation. Because of this, it has been associated with changes to brain morphology. Rat models can be useful to understand the physiological consequences of AN during both the disease and after weight recovery. PURPOSE: Use MRI analysis to determine the effect of simulated AN on brain matter volume during low weight status and following weight recovery. HYPOTHESIS: If food intake is restricted to simulate AN, brain matter volume will decrease and not fully recover following weight gain. METHODS: Female Sprague Dawley rats, 8 weeks of age, underwent simulated AN for 30 days with 50-60% food restriction. One cohort with simulated AN was euthanized, and their brains were imaged immediately after (AN, n=8). Another cohort was allowed ad libitum food consumption for an additional 30 days following AN, to allow for weight recovery (AN-R, n=6). AN and AN-R rats were compared to age matched control rats (CON and CON-R respectively, n=6-8/group). After the images were processed, ImageJ was used to quantify total brain volume and gray matter volume. The data were compared by a T-test with the significance denoted at p<0.05. RESULTS: The AN rats had lower total brain volume compared to the CON rats (79354 + 873 v. 84674 + 942 mm3, p=0.002). Gray matter volume was also lower in AN rats compared to the CON (68088 + 591 v. 74201 + 700 mm3, p<0.001). The total brain volume and gray matter volume was lower in AN-R compared to CON-R but did not reach statistical significance (81158 +1867 v. 86065 + 2017 mm3, p=0.10) and (70894 + 1675 v. 74184 + 1810 mm3, p=0.21). CONCLUSION: Brain volume and corresponding gray matter volume were altered following simulated AN, suggesting our rat model sufficiently recapitulates the brain matter alterations associated with AN. It is possible these alterations do not resolve with weight restoration; however larger sample sizes may be needed to support this hypothesis. This study was supported by NIH grant K12HD051959 and the Beth Israel Translational Spark Hubs Grant. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.