Effects of circadian disturbances on physiology and behavior of a unique diurnal model animal, the fat sand rat

The comorbid relationship between depression, cardiovascular diseases (CVD) and type 2 diabetes mellitus (T2DM) is repeatedly described in the literature. Whereas the underlying mechanisms connecting CVD and T2DM are somewhat understood, the relationship between these two very common chronic diseases with depression is well-documented clinically but not yet understood at the mechanistic level. Yet, depression, CVD and T2DM have been strongly linked with circadian rhythm disturbances. We are using a unique model animal, the fat sand rat (Psammomys obesus) to study the underlying biology of these relationships.

We demonstrated that mild interference with circadian rhythms in the sand rat can accelerate the development of T2DM, obesity and cardiac hypertrophy. Interference with the sand rat circadian rhythms can also lead to the development of a depressive- and anxiety-like behavioral phenotype that is ameliorated by antidepressant treatment, increased physical activity (voluntary wheel running) and bright white or blue light treatment. We are currently studying these changes at the behavioral, physiological and molecular levels.