OBJECTIVE: To explore the effect mechanism of electroacupuncture (EA) for ameliorating diabetic peripheral neuropathy (DPN) based on the analysis of gut microbiota and metabolomics. METHODS: Thirty SPF-grade male SD rats were randomly divided into a normal group, a model group, and an EA group, with 10 rats in each one. Except in the normal group, the intraperitoneally injection with streptozotocin was used to induce diabetes mellitus model in the rest groups. In the EA group, acupuncture was delivered at bilateral "Zusanli" (ST36), "Sanyinjiao" (SP6), "Pishu" (BL20) and "Shenshu" (BL23), and electric stimulation was attached to "Zusanli" (ST36)-"Sanyinjiao" (SP6) and "Pishu" (BL20)-"Shenshu" (BL23), on the same side, with continuous wave and a frequency of 2 Hz, for 10 min in each intervention. The intervention measure of each group was delivered once every 2 days, 3 times a week, for 8 consecutive weeks. Body weight, random blood glucose (RBG), thermal withdrawal latency (TWL), and mechanical withdrawal threshold (MWT) before intervention, and in 4 and 8 weeks of intervention, separately, as well as sensory nerve conduction velocity (SCV) and motor nerve conduction velocity (MCV) of the sciatic nerve after intervention were measured. Metagenomic sequencing (MS) was used to analyze gut microbiota and screen for differential species. Liquid chromatography-mass spectrometry (LC-MS) was employed to detect the differential metabolites in plasma, and the metabolic pathway enrichment analysis was performed on the differential metabolites. Spearman correlation analysis was adopted to assess the relationship between gut microbiota and metabolomics. RESULTS: After 4 and 8 weeks of intervention, when compared with the model group, the EA group showed the increase in body weight, TWL, MWT (P<0.01), and the decrease in RBG (P<0.01). Compared with the normal group, SCV and MCV, as well as Chao1 index were dropped in the model group (P<0.01), and those were elevated in the EA group when compared with those in the model group (P<0.01). The dominant bacterial phyla of each group were Firmicutes (F) and Bacteroidota (B), the ratio of them (F/B) in the model group was lower than that of the normal group (P<0.05), and F/B in the EA group was higher when compared with that in the model group (P<0.05). In comparison with the normal group, the relative abundance increased in Prevotella, Segatella, Prevotella-hominis and Segatella-copri (P<0.05); and it decreased in Ligilactobacillus, Eubacterium, Pseudoflavonifractor, Ligilactobacillus-murinus (P<0.05) in the model group. Compared with the model group, the relevant abundance of the above mentioned gut bacteria was all ameliorated in the EA group (P<0.05, P<0.01). Among the three groups, 120 differential metabolites were identified and enriched in 28 key metabolic pathways, such as glycerophospholipid and linoleic acid, of which, glycerophospholipid was the most significantly affected pathway in EA intervention. Spearman correlation analysis showed that 6 phosphatidylcholine metabolites were significantly positively correlated with Pseudoflavonifractor and were negatively with Prevotella, Segatella, Prevotella-hominis, Segatella-copri; 5 phosphatidylethanolamine metabolites were significantly negatively correlated with Pseudoflavonifractor and positively correlated with Prevotella, Segatella, Prevotella-hominis, Segatella-copri. CONCLUSION EA may regulate metabolic pathways such as glycerophospholipid, modulate specific gut microbiota such as Pseudoflavonifractor, Prevotella, and Segatella, and the co-expressed differential metabolites like phosphatidylcholine and phosphatidylethanolamine, thereby reducing blood glucose and protecting nerve function, so as to relieve the symptoms of DPN of rats.
Animals ; Electroacupuncture ; Male ; Gastrointestinal Microbiome ; Diabetic Neuropathies/microbiology* ; Rats, Sprague-Dawley ; Rats ; Metabolomics ; Humans ; Acupuncture Points

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the intestinal flora in rats with chronic obstructive pulmonary disease (COPD) and explore its possible mechanism based on the gut-lung axis theory. METHODS: A total of 30 male SD rats of SPF grade were randomly divided into a normal control (NC) group, a model group and an EA group, 10 rats in each one. In the model group and the EA group, COPD model was established by intratracheal instillation of lipopolysaccharide combined with cigarette fumigation. In the EA group, EA was applied at bilateral "Feishu" (BL13) and "Zusanli" (ST36), with disperse-dense waves, in frequency of 4 Hz/20 Hz, current of 1-3 mA, 20 min a time, once a day for 14 days continuously. Before and after modeling, as well as after intervention, body weight was observed; after intervention, the lung function indexes (forced expiratory volume in 0.1 second [FEV_0.1], FEV_0.1/forced vital capacity [FVC]%, forced expiratory volume in 0.3 second [FEV_0.3] and FEV_0.3/FVC%) were measured, serum levels of inflammatory factors (tumor necrosis factor-α[TNF-α], interleukin-6[IL-6], interleukin-1β[IL-1β] and interleukin-10[IL-10]) were detected by ELISA, histopathology of lung and colon tissues was observed by HE staining, the intestinal flora were analyzed by 16S rRNA, and the correlations between lung function and intestinal flora were analyzed. RESULTS: Compared with the NC group, in the COPD group, the body weight and lung function indexes were reduced (P<0.01); the lung and colon tissues were damaged, the mean linear intercept (MLI) of alveolus and inflammatory cell numbers of 100 μm² in lung tissue were increased (P<0.01); the serum levels of TNF-α, IL-6 and IL-1β were increased (P<0.01, P<0.05), and the serum level of IL-10 was decreased (P<0.01); α-diversity indexes of intestinal flora were increased (P<0.01); the relative abundance of Bacteroidetes, Proteobacteria and Oscillospira, Bacteroides, Coprococcus was increased (P<0.01), the relative abundance of Firmicutes, Actinobacteria, Tenericutes, TM7 and Lactobacillus, Allobaculum, Bifidobacterium, YRC22 was decreased (P<0.01, P<0.05); 31 different expressed metabolic pathways were identified between the two groups. Compared with the COPD group, in the EA group, the body weight and lung function indexes were increased (P<0.01); the damage of lung and colon tissues was improved, the MLI of alveolus was decreased (P<0.05); the serum levels of TNF-α, IL-6 and IL-1β were decreased (P<0.05), and the serum level of IL-10 was increased (P<0.05); α-diversity indexes of intestinal flora were decreased (P<0.01); the relative abundance of Bacteroidetes, Proteobacteria and Oscillospira, Bacteroides, Coprococcus was decreased (P<0.01, P<0.05), the relative abundance of Firmicutes, Actinobacteria, Tenericutes, TM7 and Lactobacillus, Allobaculum, Bifidobacterium, YRC22 was increased (P<0.01); 35 different expressed metabolic pathways were identified between the two groups. The lung function was positive related with Actinobacteria, Tenericutes, TM7 and YRC22, and was negative related with Bacteroidetes, Proteobacteria and Oscillospira, Bacteroides, Coprococcus. CONCLUSION EA may ameliorate lung function and tissue injury of COPD by regulating intestinal flora dysbiosis and inflammatory response, suggesting an anti-inflammatory effect mediated via "gut-lung" axis.
Animals ; Pulmonary Disease, Chronic Obstructive/genetics* ; Male ; Electroacupuncture ; Rats ; Rats, Sprague-Dawley ; Lung/metabolism* ; Gastrointestinal Microbiome ; Humans ; Interleukin-6/immunology* ; Tumor Necrosis Factor-alpha/immunology* ; Intestines/microbiology* ; Interleukin-10/immunology*

Based on the similarity of chemical constituents between Panax notoginseng flowers and rhizomes, this study investigated their lipid-lowering effects and impacts on the intestinal flora of rats. The main components of P. notoginseng flowers and rhizomes were detected by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UHPLC-Q-TOF-MS) to compare their chemical similarities. A hyperlipidemia rat model was induced using a high-fat diet. After successful modeling, the rats were divided into the blank control group, blank administration group(0.090 g·kg~(-1)), model group, low-(0.045 g·kg~(-1)), medium-(0.090 g·kg~(-1)), high-dose(0.180 g·kg~(-1)) P. notoginseng flower group, P. notoginseng rhizome group(0.270 g·kg~(-1)), and simvastatin group(0.900 mg·kg~(-1)). After modeling, the rats were given intragastric administration for 3 weeks, once daily, while their body weight was recorded regularly. Before the last administration, fresh feces were collected for analysis of changes in intestinal flora using 16S rDNA high-throughput sequencing technology. One hour after the last administration, the rats were anesthetized with 1% pentobarbital sodium, and blood was collected from the abdominal aorta. Serum biochemical indexes were detected using an automatic biochemical analyzer. Organs(heart, liver, spleen, lung, and kidney) were harvested, and organ index were calculated. Liver tissue pathology was assessed through HE staining and oil red O staining. The results indicated that there were 33 identical chemical constituents in P. notoginseng flowers and rhizomes, accounting for 75.00% of the total constituents. After treatment, high-dose P. notoginseng flower group and P. notoginseng rhizome group exhibited similar effects on body weight, serum biochemical indexes, and liver histopathological conditions. Compared with model control group, the abundance of Firmicutes and Actinobacteria increased in high-dose P. notoginseng flower and rhizome groups, while the abundance of Bacteroidetes and Thermodesulfobacteria decreased. Cluster analysis showed no significant difference between the two groups. Both P. notoginseng flowers and rhizomes possess similar chemical components and lipid-lowering effects, and they can regulate the intestinal flora imbalance caused by hyperlipidemia, indicating their potential for use in hyperlipidemia treatment.
Animals ; Hyperlipidemias/microbiology* ; Panax notoginseng/chemistry* ; Rats ; Rhizome/chemistry* ; Male ; Flowers/chemistry* ; Drugs, Chinese Herbal/administration & dosage* ; Rats, Sprague-Dawley ; Hypolipidemic Agents/administration & dosage* ; Gastrointestinal Microbiome/drug effects* ; Humans ; Liver/drug effects*

Based on the high-fat diet-induced hyperlipidemia rat model, this study aimed to evaluate the lipid-lowering effect of Arisaema Cum Bile and explore its mechanisms, providing experimental evidence for its clinical application. Biochemical analysis was used to detect serum levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol(LDL-C), triglycerides(TG), and total cholesterol(TC) to assess the lipid-lowering activity of Arisaema Cum Bile. Additionally, 16S rDNA sequencing and metabolomics techniques were employed to jointly elucidate the lipid-lowering mechanisms of Arisaema Cum Bile. The experimental results showed that high-dose Arisaema Cum Bile(PBA-H) significantly reduced serum ALT, AST, LDL-C, TG, and TC levels(P<0.01), and significantly increased HDL-C levels(P<0.01). The effect was similar to that of fenofibrate, with no significant difference. Furthermore, Arisaema Cum Bile significantly alleviated hepatocyte ballooning and mitigated fatty degeneration in liver tissues. As indicated by 16S rDNA sequencing results, PBA-H significantly enhanced both alpha and beta diversity of the gut microbiota in the model rats, notably increasing the relative abundance of Akkermansia and Subdoligranulum species(P<0.01). Liver metabolomics analysis revealed that PBA-H primarily regulated pathways involved in arachidonic acid metabolism, vitamin B_6 metabolism, and steroid biosynthesis. In summary, Arisaema Cum Bile significantly improved abnormal blood lipid levels and liver pathology induced by a high-fat diet, regulated hepatic metabolic disorders, and improved the abundance and structural composition of gut microbiota, thereby exerting its lipid-lowering effect. The findings of this study provide experimental evidence for the clinical application of Arisaema Cum Bile and the treatment of hyperlipidemia.
Animals ; Gastrointestinal Microbiome/drug effects* ; Rats ; Male ; Metabolomics ; Hyperlipidemias/microbiology* ; Drugs, Chinese Herbal/administration & dosage* ; Rats, Sprague-Dawley ; Hypolipidemic Agents/pharmacology* ; Liver/metabolism* ; Humans ; Alanine Transaminase/metabolism* ; Triglycerides/metabolism* ; Aspartate Aminotransferases/metabolism*

This article aims to explore the effect and mechanism of Liujunzi Pills on the intestinal microbiota of rats with spleen Qi deficiency syndrome. The raw Rhei Radix et Rhizoma water extract(1 g·mL~(-1)) was used to prepare spleen Qi deficiency rat models. A total of 44 SD male rats were randomly divided into a control group, a model group, Liujunzi Pills groups at high(3.24 g·kg~(-1)), medium(1.62 g·kg~(-1)), low(0.81 g·kg~(-1)) doses, and Shenling Baizhu San(2.50 g·kg~(-1)) group. The drug effect was evaluated by observing the following aspects: spleen index, fecal water content, body weight, and intestinal propulsion index. Gut microbiota analysis and 16S rRNA gene sequencing were conducted on feces. Enzyme-linked immunosorbent assay(ELISA) and UV spectrophotometry were used to detect interleukin-1β(IL-1β) and adenosine triphosphate(ATP) levels in small intestine tissues. Hematoxylin-eosin staining and transmission electron microscopy were employed to observe changes in intestinal pathology and microstructure. The results show that, compared with the control group, fecal moisture content is significantly increased while spleen index, body weight, and intestinal propulsion index are significantly reduced in rats of the model group, indicating the successful establishment of the model. The above symptoms can be improved by both Shenling Baizhu San and Liujunzi Pills. Compared with the control group, in the model group, the gut microbiota abundance is changed with an unbalanced development: the abundance of beneficial bacteria within the Bacteroidetes phylum is reduced, accompanied by a significantly decreased Shannon index, and reduced signal levels of nicotinamide adenine dinucleotide phosphate(NADPH)-related enzymes relevant to mitochondria. However, Liujunzi Pills and Shenling Baizhu San can significantly improve the Bacteroidetes phylum abundance in gut microbiota, microbial diversity, and NADPH activity in the model group. Additionally, compared with the control group, the ATP level is decreased and the IL-1β level is increased in small intestinal tissues of the model group, with shorter small intestinal epithelial villi and decreased mitochondrial number. The above symptoms can be improved by Liujunzi Pills and Shenling Baizhu San. In conclusion, Liujunzi Pills can treat spleen Qi deficiency syndrome by enhancing mitochondrial function to regulate gut microbiota balance and diversity.
Animals ; Gastrointestinal Microbiome/drug effects* ; Drugs, Chinese Herbal/pharmacology* ; Male ; Rats, Sprague-Dawley ; Rats ; Qi ; Spleen/metabolism* ; Splenic Diseases/metabolism* ; Humans ; Interleukin-1beta/genetics* ; Bacteria/drug effects* ; Feces/microbiology* ; Adenosine Triphosphate/metabolism*

This study aims to investigate the mechanism through which Xiangshao Granules treat anxiety and depression using metabolomics and gut microbiota techniques, combined with animal experiments. Sixty female ICR mice were selected for the experiment and randomly divided into six groups: a control group, a model group, a low-dose Xiangshao Granules group, a medium-dose Xiangshao Granules group, a high-dose Xiangshao Granules group, and an estradiol(positive drug) group. Except for the control group, rats in other groups were induced for anxiety and depression model by ovariectomy(OVX) combined with chronic unpredictable mild stress(CUMS). After successful modeling, the mice received oral administration of Xiangshao Granules or estradiol for three weeks. Anxiety and depression behaviors in mice were evaluated using light-dark box tests, open field tests, and elevated plus-maze tests. The levels of substances closely related to anxiety and depression, such as serotonin(5-HT) and estrogen(E_2), were quantified in plasma and hippocampal tissue using enzyme-linked immunosorbent assay(ELISA). Metabolomics and 16S rDNA amplicon sequencing techniques were employed to analyze the regulatory effects of Xiangshao Granules on plasma metabolites and metabolic pathways in anxiety and depression mice, as well as their impact on the distribution of gut microbiota. Finally, the correlation between plasma metabolites and differential gut microbiota was constructed using the Spearman correlation coefficient method. Behavioral experimental results indicated that, compared to the control group, the model group exhibited significantly decreased dwell time in the light box, reduced total distance in the open field, and diminished dwell time in the open arm. In contrast, high dose of Xiangshao Granules were found to increase the dwell time in the light box and total distance in the open field. ELISA results indicated that the levels of 5-HT, gamma-aminobutyric acid(GABA), E_2 were significantly decreased, luteinizing hormone(LH), adrenocorticotropic hormone(ACTH), and corticosterone(CORT) were significantly elevated in the anxiety and depression mice, and treatment with middle, high dose of Xiangshao Granules reversed the levels of these substances. Additionally, in the anxiety and depression mouse model, the levels of follicle-stimulating hormone(FSH) were significantly increased, whereas middle, high dose of Xiangshao Granules decreased FSH levels. Metabolomics analysis revealed that Xiangshao Granules significantly changed the metabolic profile of the anxiety and depression mice, affecting central carbon metabolism, amino acid biosynthesis, and ABC transporter pathways. The results from 16S rDNA amplicon sequencing showed that Xiangshao Granules improved the relative abundance of genera such as Bacteroidia, Bacilli, Lactobacillales, and Lactobacillus. Spearman correlation analysis indicated a close association between specific differential gut microbiota and plasma differential metabolites. This study suggests that Xiangshao Granules significantly ameliorate anxiety and depression symptoms in mice by altering the levels of substances associated with these conditions, including 5-HT, GABA, E_2, LH, and ACTH. The metabolomics and gut microbiota data suggest that the therapeutic mechanism may be closely related to the regulation of amino acid biosynthesis, central carbon metabolism, and the alteration of key microbial community compositions.
Animals ; Drugs, Chinese Herbal/administration & dosage* ; Anxiety/microbiology* ; Depression/microbiology* ; Gastrointestinal Microbiome/drug effects* ; Mice ; Female ; Mice, Inbred ICR ; Metabolomics ; Serotonin/metabolism* ; Humans ; Disease Models, Animal ; Rats ; Behavior, Animal/drug effects*

Objective To explore the mechanism by which She-Ti-Zhi-Qiu decoction alleviates allergic rhinitis (AR) through gut microbiota-mediated regulation of T helper cell 17(Th17)/regulatory T cells(Treg) balance and related cytokines. Methods Twenty-eight female SD rats were randomly divided into four groups: the Control group, Model group, STZQ group, and Probiotics group. Except for the Control group, all other groups were sensitized with ovalbumin (OVA) to establish AR models. The Control and Model groups received intragastric administration of normal saline, while the STZQ group was administered She-Ti-Zhi-Qiu Decoction, and Probiotics group received probiotics. After two weeks of continuous intragastric administration, nasal mucosa, serum, peripheral blood, and colon contents were collected. The inflammation of nasal mucosal tissue was assessed via HE staining. 16S rDNA sequencing was used to detect and analyze the structure and content of bacteria in colon contents. Flow cytometry was used to detect the relative proportions of Treg and Th17 cells in peripheral blood. ELISA was used to measure the levels of Th17- and Treg-related cytokines in serum. Results Compared with the Control group, the Model group showed an inflammatory response in nasal mucosal tissue, along with increased IL-17A and IL-17E levels and decreased IL-10 levels. The percentage of Th17 cells in peripheral blood increased, while the percentage of Treg cells decreased. Beneficial bacteria in the intestine were decreased, while pathogenic bacteria were increased. Compared with the Model group, the STZQ group showed lower serum IL-17A and IL-17E levels and higher IL-10 levels. The percentage of Th17 in peripheral blood decreased, while the percentage of Treg increased. There was an increase in beneficial bacteria in the intestine and a decrease in pathogenic bacteria. The changes in the microbiota were correlated with IL-17A, IL-17E, and IL-10 levels. Conclusion She-Ti-Zhi-Qiu decoction can ameliorate the inflammation of AR by regulating gut microbiota and Th17/Treg immune balance.
Animals ; T-Lymphocytes, Regulatory/drug effects* ; Th17 Cells/drug effects* ; Gastrointestinal Microbiome/drug effects* ; Rats, Sprague-Dawley ; Drugs, Chinese Herbal/therapeutic use* ; Female ; Rhinitis, Allergic/microbiology* ; Rats ; Cytokines

OBJECTIVES: To investigate the therapeutic mechanism of Wendan Decoction for phlegm syndrome in rats with metabolic syndrome (MS). METHODS: Forty Wistar rats were randomly divided into normal control group (n=8) and 3 phlegm syndrome model groups (induced by high-fat, high-sugar, and high-salt feeding and a single-dose intraperitoneal STZ injection; n=24) treated with daily gavage of saline, Wendan Decoction (3.6 g/kg), or metformin (0.1 g/kg) for 4 weeks. General conditions and glucose and lipid metabolism parameters of the rats were monitored, and serum LPS, liver histopathology, hepatic expressions of FXR, CYP7A1 and FGFR4 and ileal expressions of FXR and FGF15 were examined. Gut microbiota structure was analyzed using 16S rDNA sequencing, and serum bile acids were quantified with UHPLC-MS/MS. RESULTS: The rat models of phlegm syndrome exhibited severe hepatic steatosis and necrosis, increased body weight, abdominal circumference, Lee's index, FBG, FINS, HOMA-IR, TG, TC, LDL and LPS, and decreased HDL level. The abundance of Bacteroidetes, Megamonas, and Bacteroides in gut microbiota increased while Firmicutes, Lachnospiraceae_NK4A136_group, isohyodeoxycholic acid, and glycohyodeoxycholic acid decreased significantly; hepatic FXR and FGFR4 expressions and ileal FXR and FGF15 expressions decreased while hepatic CYP7A1 expression increased significantly in the rat models. Treatment with Wendan Decoction effectively alleviated hepatic pathology, reduced body weight and abdominal circumference, improved glucose and lipid metabolic profiles and gut microbiota structure, and reversed the changes in hepatic and ileal protein expressions. Correlation analysis revealed that Firmicutes and Lachnospiraceae_NK4A136_group were positively correlated while Bacteroidetes, Megamonas and Bacteroides were negative correlated with the levels of isohyodeoxycholic acid and hyodeoxycholic acid. CONCLUSIONS Wendan Decoction can significantly improve metabolic profiles in rats with phlegm syndrome of MS possibly by regulating the intestinal flora-bile acid axis to modulate the intestinal flora structure and maintain bile acid homeostasis via the FXR signaling pathway.
Animals ; Gastrointestinal Microbiome/drug effects* ; Metabolic Syndrome/microbiology* ; Bile Acids and Salts/metabolism* ; Rats, Wistar ; Drugs, Chinese Herbal/therapeutic use* ; Rats ; Male ; Fibroblast Growth Factors/metabolism* ; Liver/metabolism* ; Cholesterol 7-alpha-Hydroxylase/metabolism* ; Receptors, Cytoplasmic and Nuclear/metabolism*

OBJECTIVES: To investigate the causal relationship between gut microbiota and kidney stones. METHODS: Mendelian randomization analysis was conducted based on data from the MiBioGen consortium gut microbiota GWAS (exposure factors) and the IEU Open GWAS kidney stone dataset ukb-b-8297 (outcome variables) using the inverse variance weighted, MR-Egger regression, weighted median, weighted mode, and simple mode methods. Heterogeneity, pleiotropy, and leave-one-out sensitivity analyses were also performed. In the animal experiment, 12 male SD rats were randomized into control group with saline treatment and kidney stone model group treated with 1% ethylene glycol and 2% ammonium chloride for 28 consecutive days. Urine, blood, and intestinal samples of the rats were collected for testing the changes in renal function and intestinal barrier-related indicators, and kidney and colon pathologies were examined with histological staining and immunohistochemistry. The changes in diversity and abundance of gut microbiota were analyzed using 16S rRNA gene sequencing. RESULTS: Mendelian randomization analysis showed that decreased abundances of Lachnospiraceae NK4A136 group (OR=0.9974, 95% CI: 0.9948-0.9999, P=0.0393) and Gordonibacter (OR=0.9987, 95% CI: 0.9974-0.9999, P=0.0403) were associated with an increased risk of kidney stones without significant heterogeneity or horizontal pleiotropy, and sensitivity analyses suggested robustness of the results. The rat models of kidney stones exhibited significant renal function impairment and calcium oxalate crystal deposition, accompanied by decreased expressions of intestinal barrier-related proteins with lowered intestinal α- and β-diversity indices. Intestinal Gordonibacter abundance was significantly reduced in the rat models while the Lachnospiraceae NK4A136 group did not differ significantly between the control and model groups. CONCLUSIONS Decreased Gordonibacter abundance in gut microbiota is associated with an increased risk of kidney stones. The protective role of the Lachnospiraceae NK4A136 group against kidney stones as suggested by Mendelian randomization analysis fails to be supported by the experimental evidence and awaits further investigation.
Animals ; Kidney Calculi/microbiology* ; Gastrointestinal Microbiome ; Mendelian Randomization Analysis ; Rats, Sprague-Dawley ; Rats ; Male ; Disease Models, Animal ; Intestines/microbiology* ; RNA, Ribosomal, 16S/genetics*

OBJECTIVE: To investigate the effects of liriodendrin on the intestinal flora and the ferroptosis signaling pathway in renal tissue of rats with sepsis-induced acute kidney injury (AKI). METHODS: Thirty male Sprague-Dawley (SD) rats were randomly divided into sham operation group (Sham group), sepsis model induced by cecal ligation and puncture group (CLP group), and liriodendrin intervention group (CLP+LIR group), with 10 rats in each group. The CLP+LIR group was given 0.2 mL of 100 mg/kg liriodendrin by gavage 2 hours before modeling; Sham group and CLP group were given the same volume of normal saline by gavage. The samples were collected after anesthesia 24 hours after modeling. The pathological changes of renal tissue were observed by hematoxylin-eosin (HE) staining. The levels of inflammatory factors such as tumor necrosis factor-α (TNF-α), interleukins (IL-1β, IL-6) were detected by enzyme linked immunosorbent assay (ELISA). The levels of renal function indicators such as creatinine (Cr), and urea nitrogen (UREA) in peripheral blood, and the content of malondialdehyde (MDA) and Fe²⁺ in renal tissue were detected. Western blotting was used to detect the expressions of nuclear factor E2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPX4) and heme oxygenase-1 (HO-1) in renal tissues. The changes of intestinal flora were detected by 16S rDNA high-throughput sequencing. RESULTS: Compared with the Sham group, the CLP group showed significantly enlarged glomeruli, noticeable renal interstitial edema, disorganized kidney tissue, and significantly increased pathological scores. The contents of TNF-α, IL-1β, IL-6, Cr, and UREA in peripheral blood and the levels of MDA and Fe²⁺ in renal tissue were significantly increased. The protein expressions of Nrf2, GPX4, and HO-1 in renal tissue were significantly down-regulated. The species richness of intestinal flora decreased significantly, and the relative abundances of pathogenic bacteria such as Morganella, Citrobacter, Proteus, Klebsiella, Shigella, Aggregatibacter, and Enterococcus increased significantly, while the relative abundances of beneficial bacteria such as Butyricimonas, Veillonella, Prevotella, Lactobacillus, Bifidobacterium, and Ruminococcus decreased significantly. Compared with the CLP group, CLP+LIR group could significantly reduce the pathological damage of renal tissue, the pathological score significantly decreased (1.80±0.84 vs. 4.20±1.30, P < 0.05), and improve the composition of intestinal flora, reduce the relative abundances of pathogenic bacteria such as Proteus, Klebsiella, Shigella, Aggregatibacter, and Enterococcus, and significantly increase the relative abundances of Lactobacillus, Bifidobacterium, and Ruminococcus, significantly reduce the contents of TNF-α, IL-1β, IL-6, Cr, and UREA in peripheral blood and the levels of MDA and Fe²⁺ in renal tissue [blood TNF-α (ng/L): 191.31±7.23 vs. 254.90±47.89, blood IL-1β (ng/L): 11.15±4.04 vs. 23.06±1.67, blood IL-6 (ng/L): 163.20±17.83 vs. 267.69±20.92, blood Cr (μmol/L): 24.14±4.25 vs. 41.17±5.43, blood UREA (mmol/L): 4.59±0.90 vs. 8.01±1.07, renal MDA (μmol/g): 9.67±0.46 vs. 16.05±0.88, renal Fe²⁺ (mg/g): 0.71±0.07 vs. 0.93±0.04, all P < 0.05], and increase the protein expressions of Nrf2, GPX4, and HO-1 (Nrf2/GAPDH: 1.21±0.01 vs. 0.39±0.01, GPX4/GAPDH: 0.74±0.04 vs. 0.48±0.04, HO-1/GAPDH: 0.91±0.01 vs. 0.41±0.02, all P < 0.05). CONCLUSIONS Liriodendrin has an obvious protective effect on sepsis-induced AKI. The mechanism may involve regulating the intestinal flora, increasing the activation of the Nrf2/HO-1/GPX4 signaling pathway in renal tissue, and reducing ferroptosis.
Animals ; Acute Kidney Injury/microbiology* ; Rats, Sprague-Dawley ; Sepsis/complications* ; Male ; Ferroptosis/drug effects* ; Gastrointestinal Microbiome/drug effects* ; Rats ; Signal Transduction ; Kidney/metabolism* ; Tumor Necrosis Factor-alpha/metabolism*