Predictive behaviors for anxiety and depression in female Wistar rats subjected to cafeteria diet and stress

Obesity and chronic stress have been considered important public health problems that affect millions of people worldwide. Our aim was to analyze the effect of obesity associated with chronic stress on neurobehavioral parameters in female rats, considering that the association of these syndromes can enhance the negative effects on homeostasis. The animals were distributed into standard diet (Std), standard diet + stress (Std + stress), cafeteria diet (Cafe), and cafeteria diet + stress (Cafe + stress) groups. The animals of groups Std and Std + stress were fed with rodent standard feed. Groups Cafe and Cafe + stress, additionally to the standard feed, were offered palatable and calorie-rich processed food and cola-type soft drink ad libitum. From the eighth experimental week, groups Std + stress and Cafe + stress were subjected to restraint chronic stress model (50 days). After the stress protocol, predictive anxiety (open-field and elevated plus-maze tests) and depression (forced swim) were applied. The cafeteria diet was effective in inducing obesity. The ratio locomotion in the central quadrants/total locomotion evaluated during the open field test was not indicative of anxiogenic or anxiolytic effect in the animal's behavior. However, the elevated plus maze test showed that obese and stressed animals were prone to higher anxiety levels. In addition, the obese and stressed animals display less climbing behavior than all the other groups, which can be considered an indicator of depression-like behavior. Nevertheless, it is suggested that the mechanisms involved in effects of obesity associated with chronic stress be better investigated in female rats, considering the organic complexity related to these modem illnesses. (C) 2015 Elsevier Inc. All rights reserved.