Metabolic effects induced by chronic stress in the amygdala of diabetic rats: A study based on ex vivo 1H NMR spectroscopy

Curcumin Alleviates DSS-Induced Anxiety-Like Behaviors via the Microbial-Brain-Gut Axis

The anxiety and depression caused by inflammatory bowel diseases (IBD) are known to greatly affect the mental health of patients. The mechanism of psychiatric disorders caused by IBD is not fully understood. Previous research has suggested that the gut microbiome plays a key role in IBD. Curcumin is a yellow polyphenol extracted from the rhizome of the ginger plant, which has been shown to have effects against both depression and anxiety. Research has indicated that curcumin affects the gut microbiome and exerts antianxiety and neuroprotective effects through the microbiota-gut-brain axis (MGB). However, whether curcumin can alleviate the psychiatric disorders caused by IBD and how curcumin affects the MGB axis through the gut microbiota have not been fully understood. Therefore, this study was aimed at determining the metabolic parameters and microbiological environment in the peripheral and central nervous system to determine the effects of curcumin against anxiety induced by dextran sulfate sodium salt (DSS) in mice. To elaborate on the link between the gut microbiota and how curcumin alleviates anxiety-like behaviors, we performed a fecal microbiota transplantation (FMT) experiment. The results suggested that curcumin can effectively relieve anxiety-like behaviors caused by DSS in mice. Further, curcumin treatment can alleviate disturbances in the gut microbiota and systemic disorders of lipid metabolism caused by DSS. Finally, through FMT, we verified that curcumin increased phosphatidylcholine in the prefrontal cortex of the mice and alleviated DSS-induced anxiety-like behaviors by modulating specific gut microbiota. We also revealed that Muribaculaceae may be a key part of the gut microbiota for curcumin to alleviate DSS-induced anxiety-like behaviors through the MGB axis.

Multi-omics analysis of pathological changes in the amygdala of rats subjected to chronic restraint stress

OBJECTIVE

Overwhelming stress potentially results in the occurrence of many mental diseases. The amygdala is one region in the brain targeted by stress. Recent studies have shown that changes in the amygdala of subjects under stress are related to depression, anxiety and post-traumatic stress disorder (PTSD). However, researchers have not clearly elucidated the changes in the amygdala in response to stress and the underlying mechanism. We conducted several experiments to understand this mechanism.

METHODS

In this study, we first established a rat model of chronic restraint stress (CRS) and observed the changes in behavior and neurons in the amygdala. Second, an integrated metabolomics and proteomics experiment was conducted to identify potential stress-related biomarkers. Finally, we validated two molecules of interest and detected four apoptosis-related proteins using Western blotting to further determine the related mechanisms.

RESULTS

Our study revealed the presence of anxiety-like behaviors and pathological changes in amygdalar neurons in the rat model. In the multi-omics analysis, 19 potential molecules were identified. Western blotting confirmed consistent changes in the levels of Cry1 and Brcc36 obtained in previous results. The levels of proteins in the ataxia telangiectasia mutated (ATM) pathway were increased in the CRS group.

CONCLUSIONS

CRS causes anxiety-like behaviors that are potentially related to decreased levels of GABA in the amygdala. Moreover, CRS potentially alters the levels of Cry1 and Brcc36 and results in circadian rhythm disorder and impairments in DNA repair and apoptosis in the amygdala through a mechanism mediated by the ATM pathway.

5-Fluorouracil induced dysregulation of the microbiome-gut-brain axis manifesting as depressive like behaviors in rats

Disturbances of the gut microbiome have been widely suggested to be associated with 5-fluorouracil (5-Fu) induced digestive pathologies. Furthermore, it has been elucidated that the gut microbiome may play a key role in the pathogenesis of depressive disorders via the microbiota-gut-brain axis. Despite the speculation, there exists no direct evidence proving the causality between disturbances in the gut microbiome induced by 5-Fu and depressive mood dysregulation. Herein, behavioral testing was used to evaluate depressive-like behaviors in 5-Fu treated rats. Subsequently, the gut microbiota and prefrontal cortex (PFC) metabolic were analyzed by 16S rRNA sequencing and ¹H nuclear magnetic resonance (¹H NMR). To clarify the association between the gut microbiota and their role on depressive-like behaviors caused by 5-Fu, a fecal microbiota transplantation (FMT) experiment was carried out. The results suggested that 5-Fu could significantly alter the diversity and abundance of the gut microbiome, and induce PFC metabolic disorders, as well as depressive behaviors in rats. Transplantation of fecal microbiota from healthy control into 5-Fu treated rats significantly alleviated the PFC metabolic disorder and depressive-like behaviors. In conclusion, this study demonstrated that the gut microbiome was actively involved in the occurrence of 5-Fu induced depressive-like behaviors, and manipulation of specific gut microbiome parameters may serve as a promising novel target for side effects of 5-Fu treatment.