Short-term Cafeteria Diet Is Associated with Fat Mass Accumulation, Systemic and Amygdala Inflammation, and Anxiety-like Behavior in Adult Male Wistar Rats

Chronic Variable Stress and Cafeteria Diet Combination Exacerbate Microglia and c-fos Activation but Not Experimental Anxiety or Depression in a Menopause Model

The menopause transition is a vulnerable period for developing both psychiatric and metabolic disorders, and both can be enhanced by stressful events worsening their effects. The present study aimed to evaluate whether a cafeteria diet (CAF) combined with chronic variable stress (CVS) exacerbates anxious- or depressive-like behavior and neuronal activation, cell proliferation and survival, and microglia activation in middle-aged ovariectomized (OVX) rats. In addition, body weight, lipid profile, insulin resistance, and corticosterone as an index of metabolic changes or hypothalamus-pituitary-adrenal (HPA) axis activation, and the serum pro-inflammatory cytokines IL-6, IL-β, and TNFα were measured. A CAF diet increased body weight, lipid profile, and insulin resistance. CVS increased corticosterone and reduced HDL. A CAF produced anxiety-like behaviors, whereas CVS induced depressive-like behaviors. CVS increased serum TNFα independently of diet. A CAF and CVS separately enhanced the percentage of Iba-positive cells in the hippocampus; the combination of factors further increased Iba-positive cells in the ventral hippocampus. A CAF and CVS increased the c-fos-positive cells in the hippocampus; the combination of factors increased the number of positive cells expressing c-fos in the ventral hippocampus even more. The combination of a CAF and CVS generates a slight neuroinflammation process and neuronal activation in a hippocampal region-specific manner and differentially affects the behavior.

Supplementation with Jatobá-do-cerrado flour (Hymenaea stigonocarpa Mart.) decreases hypothalamic inflammation and improves obesity parameters in rats on a high-fat diet

To evaluate the impact of jatobá-do-cerrado flour on nutritional, inflammatory, and oxidative stress markers, an study was conducted using male Wistar rats. These animals were allocated into four groups: a standard diet (Control), a high-fat diet (HFD), a diet with jatobá-do-cerrado flour (JCF), and a combination of high-fat diet and jatobá-do-cerrado flour (HFD + JCF). Comprehensive evaluations included food intake, cytokine concentrations, and redox status indicators. HFD group exhibited increased caloric intake and fat mass, elevated circulating IL-6, and heightened lipid peroxidation markers. This group also showed increased hypothalamic concentrations of IL-6, TNFα, and lipid peroxidation. In contrast, the HFD + JCF group showed reduced caloric intake, fat mass, and improvements in redox balance and inflammatory markers both in the blood and hypothalamus. SUMMARY: In the current study, we evaluated the potential of Jatobá-do-cerrado flour in mitigating the effects of a high-fat diet in adult Wistar rats. The addition of fat to the animals' diet for 63 days induced obesity, dyslipidemia, as well as an increase in inflammatory and lipid peroxidation markers, both in the blood and hypothalamus. Conversely, supplementation with Jatobá-do-Cerrado flour showed anti-obesogenic effects and these may be associated with the reduction of inflammation and oxidative stress. Therefore, supplementation with this flour has the potential to be a functional food for the treatment or prevention of obesity.

High-intensity interval training improves long-term memory and increases hippocampal antioxidant activity and BDNF levels in ovariectomized Wistar rats

Menopause is the period in which women cease to produce the hormone estrogen, which can trigger physiological, cognitive, and behavioral changes. In this context, alternatives are needed that can reduce the effects provided by menopause, specifically in terms of cognitive and behavioral aspects. High-intensity interval training (HIIT) is an exercise protocol that has shown the potential to improve cognition by promoting an increase in antioxidant defenses and BDNF levels. Therefore, the aim of this study was to evaluate the effects of HIIT on behavior and hippocampal neurochemistry in ovariectomized adult rats. Four groups of rats were divided into: females without ovariectomy surgery and sedentary (SHAM-SED); females with ovariectomy surgery and sedentary (OVX-SED); females without ovariectomy surgery and trained (SHAM-HIIT); females with ovariectomy surgery and trained (OVX-HIIT). After the surgical procedure and the HIIT protocol, the animals underwent anxiety (elevated plus maze and open field) and memory (novel object recognition) tests. Corticosterone was measured in blood and BDNF levels and redox status were evaluated in the hippocampus. The OVX-SED group showed low BDNF levels and antioxidant enzymes, which may be linked to the observed memory impairments. The HIIT protocol (SHAM-HIIT and OVX-HIIT groups) increased the BDNF levels and antioxidant enzymes in the hippocampus, improving the animals' memory. However, HIIT also led to increased plasma corticosterone and anxiety-like behaviors. The ovariectomy procedure induced memory impairment probably due to reductions in hippocampal BDNF levels and redox imbalance. The HIIT protocol demonstrates promising results as an alternative to improve memory in ovariectomized rats.

Consumption of cashew nut induced anxiolytic-like behavior in dyslipidemic rats consuming a high fat diet

This study aimed to evaluate the effect of cashew nut consumption on anxiety-like behavior in dyslipidemic rats. The groups formed were: Control (CONT), Dyslipidemic (DL) and Dyslipidemic cashew nuts (DLCN). Tests to assess anxiety parameters were performed after the treatment period. Brain fatty acid profiles were analyzed. The animals in the DLCN group showed more rearing than DL, without differing from the CONT and less grooming than either the DL and CONT in the Open Field. In the Elevated Plus Maze, DLCN spent more time on the open arms and in the central area compared to the other groups. As for brain fatty acids, there was a reduction in polyunsaturated fatty acids for the DLCN compared to the other groups. The cashew nut, rich in fatty acids, phenolic and flavonoid compounds, reduced the anxiogenic-like behavior caused by dyslipidemia in rats without altering brain fatty acids.

Diet and obesity effects on cue-driven food-seeking: insights from studies of Pavlovian-instrumental transfer in rodents and humans

Our modern environment is said to be obesogenic, promoting the consumption of calorically dense foods and reducing energy expenditure. One factor thought to drive excess energy intake is the abundance of cues signaling the availability of highly palatable foods. Indeed, these cues exert powerful influences over food-related decision-making. Although obesity is associated with changes to several cognitive domains, the specific role of cues in producing this shift and on decision-making more generally, remains poorly understood. Here we review the literature examining how obesity and palatable diets affect the ability of Pavlovian cues to influence instrumental food-seeking behaviors by examining rodent and human studies incorporating Pavlovian-instrumental transfer (PIT) protocols. There are two types of PIT: (a) general PIT that tests whether cues can energize actions elicited in the pursuit of food generally, and (b) specific PIT which tests whether cues can elicit an action that earns a specific food outcome when faced with a choice. Both types of PIT have been shown to be vulnerable to alterations as a result of changes to diet and obesity. However, effects appear to be driven less by increases in body fat and more by palatable diet exposure per se. We discuss the limitations and implications of the current findings. The challenges for future research are to uncover the mechanisms underlying these alterations to PIT, which appear unrelated to excess weight itself, and to better model the complex determinants of food choice in humans.