[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 ( 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.