Neuropsychiatric Sequelae of Early Nutritional Modifications: A Beginner's Guide to Behavioral Analysis

The impact of high-fat diet consumption and inulin fiber supplementation on anxiety-related behaviors and liver oxidative status in female Wistar rats

BACKGROUND

Obesity is a worldwide public health problem associated with cognitive and mental health problems in both humans and rats. Studies assessing the effect of fiber supplementation on behavioral deficits and oxidative stress caused by high-fat diet (HFD) consumption in female rats are still scarce. We hypothesized that HFD consumption would lead to anxiety-related behavior and hepatic oxidative stress and that inulin would protect against these changes. We analyzed the impact of HFD-induced obesity combined with fiber supplementation (inulin) on anxiety-related defensive behavior and hepatic oxidative stress.

RESULTS

Female rats were fed a high-fat diet (HFD; 45%) for nine weeks to induce obesity. The administration of inulin was found to decrease the adiposity index in both the control and obese groups. The consumption of a HFD combined with inulin supplementation resulted in a reduction in both CAT activity and carbonylated protein levels, leading to a shift in the hepatic redox balance. Interestingly, the behavioral data were conflicting. Specifically, animals that consumed a high-fat diet and received inulin showed signs of impaired learning and memory caused by obesity. The HFD did not impact anxiety-related behaviors in the female rats. However, inulin appears to have an anxiolytic effect, in the ETM, when associated with the HFD. On the other hand, inulin appears to have affected the locomotor activity in the HFD in both open field and light-dark box.

CONCLUSION

Our results show that consumption of a HFD induced obesity in female rats, similar to males. However, HFD consumption did not cause a consistent increase in anxiety-related behaviors in female Wistar rats. Treatment with inulin at the dosage used did not exert consistent changes on the behavior of the animals, but attenuated the abdominal WAT expansion and the hepatic redox imbalance elicited by high-fat diet-induced obesity.

Role of Neuronal TRPC6 Channels in Synapse Development, Memory Formation and Animal Behavior

The transient receptor potential cation channel, subfamily C, member 6 (TRPC6), has been believed to adjust the formation of an excitatory synapse. The positive regulation of TRPC6 engenders synapse enlargement and improved learning and memory in animal models. TRPC6 is involved in different synaptoprotective signaling pathways, including antagonism of N-methyl-D-aspartate receptor (NMDAR), activation of brain-derived neurotrophic factor (BDNF) and postsynaptic store-operated calcium entry. Positive regulation of TRPC6 channels has been repeatedly shown to be good for memory formation and storage. TRPC6 is mainly expressed in the hippocampus, particularly in the dentate granule cells, cornu Ammonis 3 (CA3) pyramidal cells and gamma-aminobutyric acid (GABA)ergic interneurons. It has been observed that TRPC6 agonists have a great influence on animal behavior including memory formation and storage The purpose of this review is to collect the available information on the role of TRPC6 in memory formation in various parts of the brain to understand how TRPC6-specific pharmaceutical agents will affect memory in distinct parts of the central nervous system (CNS).

Benefits of Fenofibrate in prenatal valproic acid-induced autism spectrum disorder related phenotype in rats

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with two major behavioral symptoms i.e. repetitive behavior and social-communication impairment. The unknown etiology of ASD is responsible for the difficulty in identifying the possible therapeutic modulators for ASD. Valproic acid (VPA) is an anticonvulsant drug in both human and rodents with teratogenic effects during pregnancy. Therefore, prenatal exposure of VPA induced autism spectrum disorder like phenotypes in both human and rodents. Peroxisome proliferator-activated receptor-alpha (PPAR-α) is widely localized in the brain. This research investigates the utility of fenofibrate, a selective agonist of PPAR-α in prenatal VPA-induced experimental ASD in Wistar rats. The prenatal VPA has induced social impairment (three chambers social behavior apparatus), repetitive behavior (Y-maze), hyperlocomotion (actophotometer), anxiety (elevated plus maze) and low exploratory activity (hole board test). Also, prenatal VPA treated rats have shown higher levels of oxidative stress (increased in thiobarbituric acid reactive species and decreased in reduced glutathione level) and inflammation (increased in interleukin-6, tumor necrosis factor-α and decreased in interleukin-10) in the cerebellum, brainstem and prefrontal cortex. Treatment with fenofibrate significantly attenuated prenatal VPA-induced social impairment, repetitive behavior, hyperactivity, anxiety, and low exploratory activity. Furthermore, fenofibrate also decreased the prenatal VPA-induced oxidative stress and inflammation in brain regions. Hence, it may be concluded that fenofibrate may provide neurobehavioral and biochemical benefits in prenatal VPA-induced autism phenotypes in rats.

The Elevated Plus Maze Test for Measuring Anxiety-Like Behavior in Rodents

The elevated plus maze test is used to measure anxiety-like behavior in rodents. It can be used to gain insight into conditions such as posttraumatic stress disorder (PTSD) and other conditions marked by anxious behavior. It can also be used as a component in screening of novel compounds for anxiolytic properties. This model is based on aversion to open spaces, which is seen as the animal spending more time in the enclosed arms of the maze. This chapter describes the steps necessary for setting up and conducting the test, along with interpretation of the results.