Central Area Of Open Field Research Articles

Bacillus amyloliquefaciens SC06 attenuated high-fat diet induced anxiety-like behavior and social withdrawal of male mice by improving antioxidant capacity, intestinal barrier function and modulating intestinal dysbiosis

Anxiety-like behavior and social withdrawal induced by obesity and oxidative stress are significant health concerns in contemporary society. Our previously study found that Bacillus amyloliquefaciens SC06 (SC06) decreased the body weight of high-fat diet (HFD)-fed male mice and protected porcine intestinal epithelial cells against oxidative stress. The present study further investigated the effect of SC06 on HFD-induced obesity, anxiety-like behavior and social withdrawal of male mice and explored its mechanism. Results showed that SC06 significantly decreased HFD-induced obesity as evidenced by the decreased body weight, weight of liver and epididymal fat. Meanwhile, SC06 attenuated the anxiety-like behavior of HFD-fed male mice as illustrated by the more exploration time in both the open arms of elevated plus maze and the central area of open field and the reversed their social withdrawal tested in the three-chamber social choice task. SC06 also reduced reactive oxygen species (ROS) concentration and normalized the mitochondrial morphology in the hippocampus. SC06 reduced the systemic inflammation and increased the expression of intestinal tight junctions (ZO-1 and Claudin1). Furthermore, SC06 also altered the microbial diversity and composition, and decreased Firmicutes to Bacteroidetes ratio of HFD-fed male mice. These findings suggest SC06 attenuate HFD-induced anxiety-like behavior and social withdrawal of male mice by attenuating hippocampal oxidation stress, systemic inflammation, dysbiosis and improving intestinal barrier function.

Effects of B-GOS on cognitive behavior and depression of transgenic mice with Alzheimer's disease

Objective: To investigate the effects of novel BimunoGalactooligosaccharides (B-GOS) on cognitive behavior and depression of APP/PS1/tau Alzheimer's disease transgenic mice. Methods: Five-month-old male APP/PS1/tau AD transgenic mice and C57BL/6J control mice were divide into C57+Vehicle group, C57+B-GOS group, APP/PS1/tau+Vehicle group and APP/PS1/tau+B-GOS group, with 10 mice in each group. After continuous administration of B-GOS for 5 months, the cognitive behavior and depressive mood changes of mice in each group were detected by open field experiment, new object recognition experiment, Y maze experiment, Morris water maze experiment, tail suspension test, forced swimming test and conditioned fear experiment, respectively. Results: ①Open field experiment: the percentage of activity time in the central area of open field in APP/PS1/tau+Vehicle group mice was significantly lower than that in C57+Vehicle group mice (P＜0.01), and was remarkably increased after B-GOS intervention (P＜0.05). ② New object recognition experiment: the new object recognition index (NOI) of APP/PS1/tau+Vehicle group mice was significantly lower than that of C57+Vehicle group mice (P＜0.01), and was observably increased after B-GOS intervention (P＜0.05). ③ Y maze experiment: the spontaneous alternation correct rate of APP/PS1/tau+Vehicle group mice was notably lower than that in C57+Vehicle group (P＜0.01), and was distinctly increased after B-GOS intervention (P＜0.01). ④ Classical water maze experiment: the escape latency of APP/PS1/tau+Vehicle group mice on the 4th and 5th days was significantly longer than that of C57+Vehicle group mice (P＜0.01), which was markedly shortened after B-GOS intervention (P＜0.05). During the space exploration phase, the percentage of swimming time in the target quadrant and the times of crossing the platform in APP/PS1/tau+Vehicle group mice were significantly lower than those in C57+Vehicle group mice (P＜0.01), which were notably increased after B-GOS intervention (P＜0.01). ⑤ Tail suspension test and forced swimming test: the percentage of immobility time in APP/PS1/tau+Vehicle group mice was dramatically higher than that in C57+Vehicle group mice (P＜0.01), and was obviously reduced after B-GOS intervention (P＜ 0.01). ⑥ Conditioned fear experiment: before conditioned stimulus (CS), the freezing ratio of mice in each group had no statistical difference (P＞0.05). After CS, the freezing ratio of APP/PS1/tau+Vehicle group mice was significantly lower than that of C57+Vehicle group mice (P＜0.01), and was notably increased after B-GOS intervention (P＜0.01). Conclusion: B-GOS could reverse the cognitive behavioral impairment of APP/PS1/tau mice and alleviate their depression to a large extent.

Effets de l’huile des fruits de Dacryodes edulis sur les symptômes de l’anxiété et les performances cognitives chez la souris, après administration prolongée

ObjectiveTo study the effects of prolonged administration of Dacryodes edulis (G. Don) H.J. Lam (HDE) fruit oil on the symptoms of anxiety and cognitive performance in mice. MethodsAnxiolytic activity and effects of HDE (5 and 10 ml/kg) on cognitive performance were evaluated in male mice after oral administration for 45 days. Anxiolytic effects were investigated in open field test, elevated plus Maze and hole board test. The Morris Water Maze test was used to evaluate cognitive performance in mice. Efficacy of HDE (5 and 10 ml/kg) was compared with that of fluoxetine (2 mg/kg p.o). ResultsHDE decreases the total distance traveled, significantly increases the number of adjustments and the number of entries in the central area of open field. In the elevated cross labyrinth test, HDE increases the number of entries and the time spent in the open arms. HDE significantly increases the number of head insertion into the holes. In the Morris Water Maze test, HDE reduces latency before finding the platform and increases the time spent in the target quadrant. ConclusionThe results confirm anxiolytic effects and improved cognitive performance after prolonged oral administration of HDE in rodents.

Distinct roles of neuronal and microglial CB2 cannabinoid receptors in the mouse hippocampus

The effects of cannabinoids are primarily mediated by type-1 cannabinoid receptors in the brain and type-2 cannabinoid receptors (CB2Rs) in the peripheral immune system. However, recent evidence demonstrates that CB2Rs are also expressed in the brain and implicated in neuropsychiatric effects. Diverse types of cells in various regions in the brain express CB2Rs but the cellular loci of CB2Rs that induce specific behavioral effects have not been determined. To manipulate CB2R expression in specific types of cells in the dorsal hippocampus of adult mice, we used Cre-dependent overexpression and CRISPR-Cas9 genome-editing techniques in combination with adeno-associated viruses and transgenic mice. Elevation and disruption of CB2R expression in microglia in the CA1 area increased and decreased, respectively, contextual fear memory. In CA1 pyramidal neurons, disruption of CB2R expression enhanced spatial working memory, whereas their overexpression reduced anxiety levels assessed asan increase in the exploration time in the central area of open field. Interneuronal CB2Rs were not involved in the modulation of cognitive or emotional behaviors tested in this study. The targeted manipulation of CB2R expression in pyramidal neurons and microglia suggests that CB2Rs in different types of cells in the mature hippocampus play distinct roles in the regulation of memory and anxiety.