Search

Chronic stress (CS) endangers the physical and mental health of adolescents. Therefore, alleviating and preventing such negative health impacts are a top priority. This study explores the effect of feeding shrimp head hydrolysate (SHH) on gut microbiota, short-chain fatty acids (SCFAs), and neurotransmitters in growing C57BL/6 mice subjected to chronic unpredictable mild stress. Mice in the model group and three SHH groups were exposed to CS for 44 days, distilled water and SHH doses of 0.18, 0.45, 0.90 g/kg·BW were given respectively by gavage daily for 30 days from the 15th day. The results showed that SHH can significantly reverse depression-like behaviour, amino acids degradation, α diversity and β diversity, proportion of Firmicutes and Bacteroidota, abundance of genera such as Muribaculaceae, Bacteroides, Prevotellaceae_UCG-001, Parabacteroides and Alistipes, concentration of five short-chain fatty acids (SCFAs), 5-HT and glutamate induced by CS. Muribaculaceae and butyric acid may be a controlled target. This study highlights the potential and broad application of SHH as an active ingredient in food to combat chronic stress damage.

Elephantopus scaber L. (ESL) is a Chinese herb that is used both as a food and medicine, often being added to soups in summer in south China to relieve heat stress (HS), but its exact mechanism of action is unknown. In this study, heat-stressed mice were gavaged with ESL polysaccharides (ESLP) at 0, 150, 300, and 450 mg/kg/d−1 (n = 5) for seven days. The gut microbiota composition, short-chain fatty acids (SCFAs), seven neurotransmitters in faeces, expression of intestinal epithelial tight junction (TJ) proteins (Claudin-1, Occludin), and serum inflammatory cytokines were measured. The low dose of ESLP (ESLL) improved the adverse physiological conditions; significantly reduced the cytokines (TNF-α, IL-1β, IL-6) and lipopolysaccharide (LPS) levels (p < 0.05); upregulated the expression of Claudin-1; restored the gut microbiota composition including Achromobacter and Oscillospira, which were at similar levels to those in the normal control group; significantly increased beneficial SCFAs like butyric acid and 5-HT levels in the faeces of heat-stressed mice; and significantly decreased the valeric acid and glutamic acid level. The level of inflammatory markers significantly correlated with the above-mentioned indicators (p < 0.05). Thus, ESLL reduced the HS-induced systemic inflammation by optimizing gut microbiota (Achromobacter, Oscillospira) abundance, increasing gut beneficial SCFAs like butyric acid and 5-HT levels, and reducing gut valeric and glutamic acid levels.

The present study aimed to investigate the protective effect of carboxymethyl pachymaran (CMP) on the short-term stress mice model. The behavioural tests revealed the CMP treatment can improve depression-like behaviour in the mice model. Short-term stress induced over-expression of occludin and claudin-2 proteins in the blood–brain barrier (BBB) was significantly reversed by CMP through regulation of the inflammatory cytokines-JNK/ERK/P38 pathway. Systemic inflammation caused by short-term stress was suppressed by CMP treatment through increasing concentrations of propionic, and valeric acids, and decreasing isovaleric acid concentrations in the feces. In addition, CMP elevated the levels of hippocampal 5-hydroxytryptamine (5-HT) and norepinephrine (NE). In conclusion, CMP attenuates depression-like behaviours caused by short-term stress, which may be associated with mediating the short-chain fatty acids (SCFAs)-inflammatory cytokines-ERK/JNK/p38 pathway to down-regulate the expression of occludin and claudin-2 proteins in the BBB, and also may be related to elevated levels of NE and 5-HT in the hippocampus.

Systemic low-grade inflammation induced by unhealthy diet has become a common health concern as it contributes to immune imbalance and induces chronic diseases, yet effective preventions and interventions are currently unavailable. The Chrysanthemum indicum L. flower (CIF) is a common herb with a strong anti-inflammatory effect in drug-induced models, based on the theory of “medicine and food homology”. However, its effects and mechanisms in reducing food-induced systemic low-grade inflammation (FSLI) remain unclear. This study showed that CIF can reduce FSLI and represents a new strategy to intervene in chronic inflammatory diseases. In this study, we administered capsaicin to mice by gavage to establish a FSLI model. Then, three doses of CIF (7, 14, 28 g·kg−1·day−1) were tested as the intervention. Capsaicin was found to increase serum TNF-α levels, demonstrating a successful model induction. After a high dose of CIF intervention, serum levels of TNF-α and LPS were reduced by 62.8% and 77.44%. In addition, CIF increased the α diversity and number of OTUs in the gut microbiota, restored the abundance of Lactobacillus and increased the total content of SCFAs in the feces. In summary, CIF inhibits FSLI by modulating the gut microbiota, increasing SCFAs levels and inhibiting excessive LPS translocation into the blood. Our findings provided a theoretical support for using CIF in FSLI intervention.

Certain foods are known as “heating” foods in Chinese medicine. Over-consumption of these foods can lead to symptoms known as “heating up”. These symptoms have been shown to be symptoms of systemic low-grade inflammation. However, the mechanism by which these foods cause inflammation is not clear. In this preliminary study, we investigated dysbacteriosis of the gut microbiota as a possible cause of inflammation by litchi, a typical “heating” food. A human flora-associated (HFA) mouse model (donor: n = 1) was constructed. After gavaging the mice with litchi extract suspension at low, medium and high doses (400, 800, 1600 mg/kg·d−1, respectively) (n = 3) for 7 days, the serum levels of inflammatory cytokines, gut microbiota, the concentration of SCFAs and the integrity of the intestinal mucosal barrier were measured. The results revealed significant increases in the abundance of Prevotella and Bacteroides. A significant increase in the abundance of Bilophila and a decrease in Megasomonas was observed in the high-dose group. High-dose litchi intervention led to a decrease of most SCFA levels in the intestine. It also caused a more than two-fold increase in the serum TNF-α level and LPS level but a decrease in the IL-1β and IL-6 levels. Medium- and high-dose litchi intervention caused widening of the intestinal epithelial cell junction complex and general weakening of the intestinal mucosal barrier as well as reduced energy conversion efficiency of the gut microbiota. These data suggest that litchi, when consumed excessively, can lead to a low degree of systematic inflammation and this is linked to its ability to cause dysbacteriosis of the gut microbiota, decrease SCFAs and weaken the intestinal mucosal tissues.