RESUMO
Stress exposure is a potential threat to humans who live or work in extreme environments, often leading to oxidative stress, inflammatory response, intestinal dysbiosis, and metabolic disorders. Gallnut tannic acid (TA), a naturally occurring polyphenolic compound, has become a compelling source due to its favorable anti-diarrheal, anti-oxidative, anti-inflammatory, and anti-microbial activities. Thus, this study aimed to evaluate the anti-stress effects of gallnut TA on the stress-induced inflammatory response, dysbiotic gut microbiota, and alterations of serum metabolic profile using beagle models. A total of 13 beagle dogs were randomly divided into the stress (ST) and ST + TA groups. Dietary supplementation with TA at 2.5 g/kg was individually fed to each dog in the ST + TA group for 14 consecutive days. On day 7, all dogs were transported for 3 h from a stressful environment (days 1-7) to a livable site (days 8-14). In our results, TA relieved environmental stress-induced diarrheal symptoms in dogs and were shown to protect from myocardial injury and help improve immunity by serum biochemistry and hematology analysis. Also, TA inhibited the secretion of serum hormones [cortisol (COR), glucocorticoid (GC), and adrenocorticotropic hormone (ACTH)] and the expression of heat shock protein (HSP) 70 to protect dogs from stress-induced injury, thereby relieving oxidative stress and inflammatory response. Fecal 16S rRNA gene sequencing revealed that TA stimulated the growth of beneficial bacteria (Allobaculum, Dubosiella, Coriobacteriaceae_UCG-002, and Faecalibaculum) and suppressed the growth of pathogenic bacteria (Escherichia-Shigella and Streptococcus), thereby increasing fecal butyrate levels. Serum metabolomics further showed that phytosphingosine, indoleacetic acid, arachidonic acid, and biotin, related to the metabolism of sphingolipid, tryptophan, arachidonic acid, and biotin, respectively, could serve as potential biomarkers of stress exposure. Furthermore, Spearman's correlation analysis showed strong relationships between the four potential serum biomarkers and differential bacteria. Overall, gallnut TA may be a potential prebiotic for the prevention and treatment of stress-induced metabolic disorders by targeting intestinal microbiota.
RESUMO
Liver fibrosis is a common part of the pathological development of many chronic liver diseases. As liver fibrosis progresses, it may lead to cirrhosis, portal hypertension, liver decompensation, liver tumours, and death. Camellia oil (Camellia oleifera Abel.) is widely used as an edible oil in China. It has a wide range of biological activities and is used as a traditional medicine to treat conditions such as burns and stomach pains. However, whether camellia oil can ameliorate liver fibrosis remains unclear. We constructed a liver fibrosis model induced by carbon tetrachloride (CCl4) and then confirmed the role of camellia oil in liver fibrosis by biochemical examination, histopathological morphology, immunohistochemistry, and western blot analysis. We found that camellia oil ameliorated histopathological lesions, improved liver function and antioxidant capacity, decreased the expression of TGF-ß1 and α-SMA proteins, and downregulated the expression of the pro-apoptotic proteins in CCl4-induced liver fibrosis. Therefore, these results suggest that camellia oil attenuates CCl4-induced liver fibrosis in mice, and its mechanism may function via reduction of hepatocyte apoptosis to inhibit hepatic stellate cell (HSC) activation. Camellia oil may provide a potential new treatment for liver fibrosis as an auxiliary treatment by addition of the edible oil to the daily diet.