Tibetan tea reduces obesity brought on by a high-fat diet and modulates gut flora in mice

Oyster Peptides Ameliorate Dextran Sulfate Sodium-Induced Ulcerative Colitis via Modulating the Gut Microbiota and Inhibiting the TLR4/NF-κB Pathway

Ulcerative colitis (UC) is an inflammatory bowel disease with an increasing prevalence year over year, and the medications used to treat patients with UC clinically have severe side effects. Oyster peptides (OPs) have anti-inflammatory and antioxidant properties as functional foods that can alleviate a wide range of inflammatory conditions. However, the application of oyster peptides in ulcerative colitis is not well studied. In this work, an animal model of acute colitis was established using 3% dextran sulfate sodium (DSS), and the impact of OP therapy on colitis in mice was examined. Supplementing with OPs prevented DSS-induced colitis from worsening, reduced the expression of oxidative stress and inflammatory markers, and restored the intestinal barrier damage caused by DSS-induced colitis in mice. The 16S rDNA results showed that the OP treatment improved the gut microbiota structure of the UC mice, including increasing microbial diversity, increasing beneficial bacteria, and decreasing harmful bacteria. In the UC mice, the OP therapy decreased the relative abundance of Family_XIII_AD3011_group and Prevotella_9 and increased the relative abundance of Alistipes. In conclusion, OP treatment can inhibit the TLR4/NF-κB pathway and improve the intestinal microbiota in UC mice, which in turn alleviates DSS-induced colitis, providing a reference for the treatment of clinical UC patients.

[Sichuan Dark Tea-Based Medicated Dietary Formula Improves Obesity-Induced Renal Lipid Metabolism Disorder in Mice by Remodeling Gut Microbiota and Short-Chain Fatty Acid Metabolism]

Objective

To investigate the renoprotective effects of a Sichuan dark tea-based medicated dietary formula (alternatively referred to as Qing, or clarity in Chinese) on mice with diet-induced obesity (DIO) and to explore the specific mechanisms involved.

Methods

Male C57BL/6 mice were randomly assigned to three groups, a control group, a DIO group, and a Qing treatment group, or the Qing group, with 8 mice in each group. The mice in the control group were given normal maintenance feed and purified water, and the other two groups were fed a high-fat diet for 12 weeks to establish the DIO model. After that, high-fat diet continued in the DIO group, while the Qing group was given Qing at the same time for 12 weeks, during which period the weight of the mice was monitored and recorded every week. The mice were sacrificed after 12 weeks. Serum samples were collected and the levels of triglyceride (TG), total cholesterol (TC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and albumin were measured to evaluate liver function. In addition, renal lipids were extracted to determine the levels of TG and TC in the kidney and periodic acid-Schiff (PAS) and oil red O stainings were performed to evaluate kidney pathological injury. Western blot was performed to determine the phosphorylated AMPK (pAMPK)/AMPK ratio in the kidney tissue. RT-qPCR and Western blot were used to determine the expression of proteins related to fatty acid oxidation, including acetyl-CoA carboxylase 1 (ACC1), carnitine acyltransferase 1 (CTP1), peroxisome proliferators-activated receptor γ (PPARγ), peroxisome proliferators-activated receptor-1 α (PPAR1α), sterol-regulatory element binding proteins (SREBP-1), and key proteins related to lipid synthesis, including fatty acid synthase (FASN) and stearoyl-coenzyme A desaturase 1 (stearoyl-CoA desaturase) in the kidney tissue. 16SrRNA and metabolomics were applied to analyze the gut microbiota in the intestinal contents and its metabolites.

Results

Compared with those of the control group, the levels of liver mass (P=0.0003), serum ALT (P<0.0001) and AST (P=0.0001), and kidney TC (P=0.0191) and TG (P=0.0101) of the DIO group were significantly increased and there was lipid deposition in the kidney. Compared with those of the DIO group, mice in the Qing group showed effective reduction in liver mass (P=0.0316) and improvements in the abnormal serum levels of AST (P=0.0012) and ALT (P=0.0027) and kidney TC (P=0.0200) and TG (P=0.0499). In addition, mice in the Qing group showed significant improvement in lipid deposition in the kidney. Qing group showed increased pAMPK/AMPK ratio in comparison with that of the DIO group. In comparison with those of the control group, mice in the DIO group had upregulated expression of lipid synthesis-related genes and proteins (SREBP-1, FASN, and SCD1). As for the fatty acid oxidation-related genes and proteins, DIO mice showed upregulated expression of ACC1 and downregulated expression of CPT1A, PPARγ, and PGC1α in comparison with those of the control group. In the Qing goup, improvements in regard to all these changes were observed. The Qing group demonstrated improvement in the disrupted homeostasis of the gut microbiota. Short-chain fatty acids in the cecal contents, especially isovaleric acid and propionic acid, were also restored.

Conclusion

Sichuan dark tea-based medicated dietary formula may improve renal lipid metabolism by regulating gut microbiota and the levels of intestinal short-chain fatty acids, thereby protecting obesity-related kidney injury. Isovaleric acid and propionic acid may be the metabolites key to its regulation of gut microbiota.