Effect of Liangxue Huoxue decoction on intestinal flora and NLRP3/caspase-1/GSDMD signaling pathway in mice model of sepsis-induced acute kidney injury / 中华危重病急救医学

Objective:To investigate the effect of Liangxue Huoxue decoction on intestinal flora, intestinal barrier and NOD-like receptor protein 3 (NLRP3)/caspase-1/gasdermin D (GSDMD) pyroptosis signaling pathway in mice model of sepsis-induced acute kidney injury (AKI).Methods:The model of AKI was established by cecal ligation and perforation (CLP). Thirty male C57BL/6 mice were randomly divided into sham operation group (Sham group), sepsis group (CLP group) and sepsis+Liangxue Huoxue decoction (CLP+LXHX group), with 10 mice in each group. Mice in Sham group only underwent laparotomy. Two hours before model establishment, mice in CLP+LXHX group were treated with Liangxue Huoxue decoction (6 g/kg) by gavage; mice in Sham group and CLP group were given equal volume of normal saline by gavages. After 24 hours of modeling, all mice were sacrificed under anesthesia, and the colon and kidney tissues and fresh feces in the colon were taken. The pathological changes of kidney and colon were observed by hematoxylin-eosin (HE) staining under light microscope. Real-time polymerase chain reaction (RT-PCR) was used to detect inflammatory factors (interleukins, IL-1β and IL-18) in renal tissue. The expressions of NLRP3, caspase-1 and GSDMD were detected by Western blotting. The changes of intestinal flora in mice were detected by 16S rDNA high-throughput sequencing.Results:Compared with the Sham group, the inflammatory cell infiltration of the kidney tissue was increased and the kidney became vacuolated in CLP group, the mRNA expressions of IL-1β, IL-18, and the protein expressions of NLRP3, caspase-1 and GSDMD were significantly increased in CLP group, the species richness of intestinal microflora decreased significantly, the relative abundance of Enterococcus and Escherichia-Shigella increased significantly, and the relative abundance of Ileibacterium, Alloprevotella, Lachnospiraceae, Klebsiella and Parasutterella increased significantly in CLP group. Compared with CLP group, Liangxue Huoxue decoction can significantly reduce the pathological changes of kidney and colon tissue, reduce the pathological score (1.75±0.43 vs. 3.50±0.50 for kidney tissue, 1.25±0.43 vs. 4.50±0.50 for colon tissue, both P < 0.05), improve the composition of intestinal flora, reduce the relative abundance of Enterococcus and Escherichia-Shigella, and significantly increase the relative abundance of Lactobacillus and Akkermansia. In addition, Liangxue Huoxue decoction can significantly reduce mRNA expressions of IL-1β and IL-18 in kidney tissue [IL-1β mRNA (2 -ΔΔCt): 1.59±0.05 vs. 4.61±0.88, IL-18 mRNA (2 -ΔΔCt): 1.69±0.17 vs. 2.86±0.63, both P < 0.05] and the protein expressions of NLRP3, caspase-1 and GSDMD (NLRP3/GAPDH: 0.71±0.04 vs. 0.89±0.01, caspase-1/GAPDH: 1.04±0.04 vs. 1.48±0.04, GSDMD/GAPDH: 0.90±0.01 vs. 1.41±0.02, all P < 0.05). Conclusions:Liangxue Huoxue decoction has obvious protective effect on AKI induced by sepsis. It can improve intestinal barrier by regulating intestinal flora, thereby inhibiting the activation of NLRP3/caspase-1/GSDMD signaling pathway in kidney tissue and reducing the expression of proptosis-related inflammatory factors.

Revealing the role of gut microbiota in immune regulation and organ damage in sepsis using 16s rRNA and untargeted metabolomics / 中华危重病急救医学

OBJECTIVE@#To analyze the composition and metabolites of gut microbiota in septic rats by fecal 16s rRNA sequencing and untargeted metabolomics, and to preliminarily explore the effect and potential mechanism of gut microbiota and its metabolites on inflammatory response and multiple organ damage in sepsis.@*METHODS@#Ten males healthy male Wistar rats were randomly divided into a sham operated group (Sham group) and sepsis model group (CLP group) using a random number table method, with 5 rats in each group. A rat sepsis model was established by cecal ligation and perforation (CLP) method. The animals were sacrificed 24 hours after modeling, the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in peripheral blood were detected by enzyme-linked immunosorbent assay (ELISA). Hematoxylin-eosin (HE) staining was used to observe the pathological changes of lung and kidney tissues, and the pathological scores were evaluated. Fecal samples were collected, and 16s rRNA high-throughput sequencing and non-targeted metabolomics were used to screen microbiota, metabolites and potential signal pathways that may play an important role in disease outcomes. Spearman correlation analysis was conducted to jointly analyze the gut microbiota and non-targeted metabolism.@*RESULTS@#Compared with the Sham group, the degree of pathological damage to lung and kidney tissues in the CLP group was significantly increased (lung tissue score: 3.60±0.80 vs. 0.00±0.00, kidney tissue score: 2.40±0.80 vs. 0.00±0.00, both P < 0.01), the level of IL-6 and TNF-α in peripheral blood significantly increased [TNF-α (ng/L): 248.12±55.98 vs. 143.28±36.57, IL-6 (ng/L): 260.26±39.47 vs. 116.01±26.43, both P < 0.05], the species diversity of intestinal flora of rats in the CLP group was significantly reduced, the relative abundance of Morganella, Bacteroides and Escherichia-Shigella were significantly increased, and the relative abundance of Lachnospiraceae NK4A136, Ruminococcus, Romboutsia and Roseburia were significantly reduced. In addition, the biosynthesis and bile secretion of phenylalanine, tyrosine, and tryptophan in the gut microbiota of the CLP group were significantly increased, while the biosynthesis of secondary bile acids was significantly reduced. There was a significant correlation between differential metabolites and differential microbiota.@*CONCLUSIONS@#Sepsis can cause significant changes in the characteristics of gut microbiota and fecal metabolites in rats, which provides a basis for translational research to seek new targets for the treatment of sepsis.

A study on alleviation of acute lung injury in rats with bowel repletion pattern by mesenteric lymph drainage and its mechanism / 中国中西医结合急救杂志

Objective To observe the effects of mesenteric lymph drainage on acute lung injury and expression of p38 mitogen activated protein kinase (p38MAPK) signal pathway in rats with bowel repletion pattern. Methods Thirty male Wistar rats were randomly divided into three groups according to random number table method, namely sham operation group (sham group), bowel repletion model group (model group) and mesenteric lymph drainage group (drainage group), 10 rats in each group. The rat model of bowel repletion was established by ischemia/reperfusion (I/R) method, firstly 1 hour occlusion of superior mesenteric artery (SMA) to induce ischemia followed by reperfusion for 2 hours. In the rats of drainage group, the drainage of mesenteric lymph duct began at the end of model establishment and persisted for 3 hours. In the rats of sham group, the SMA and mesenteric lymph ducts were exposed with blunt dissection, and then they were immediately placed back into the abdominal cavity. After 3 hours of mesenteric lymph drainage, the lung and ileum tissues of rats in each group were harvested for evaluation of pathohistological changes and for the determination and comparison of myeloperoxidase (MPO) activity changes; the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in bronchoalveolar lavage fluid (BALF) were detected by enzyme linked immunosorbent assay (ELISA), and the expressions of Toll-like receptor 4 (TLR4) mRNA and p38MAPK mRNA in the lung tissues were measured by fluorescence quantitative polymerase chain reaction (PCR).Results Under the light microscope, the pulmonary capillaries markedly dilated and congested, the interstitium width of lung increased with a large amount of inflammatory cells infiltration, the intestinal mucosal layer becoming thinner with detachment of intestinal villi and a large amount of inflammatory cells infiltration were detected in rats of model group. Compared with those in sham group, the levels of TNF-α and IL-6 in BALF, the MPO activity of lung and ileum tissues, and the expressions of TLR4 mRNA and p38MAPK mRNA in the lung tissues were significantly increased in model group.Compared with those in model group, the pathohistological damages in lung and ileum tissues were ameliorated, the levels of TNF-α and IL-6 in BALF, the MPO activity of lung and intestinal tissues and the expressions of TLR4 mRNA and p38MAPK mRNA in the lung tissues were lower in the rats of drainage group [TNF-α in BALF (ng/L): 858.55±27.16 vs. 1 680.58±105.62; IL-6 in BALF (ng/L): 0 vs. 484.71±5.43; MPO activity of lung (U/g): 0.95±0.13 vs. 1.36±0.11; MPO activity of ileum tissues (U/g): 0.75±0.13 vs. 1.30±0.16; TLR4 mRNA: 0.21±0.11 vs. 0.69±0.13, p38MAPK mRNA: 0.21±0.13 vs. 0.47±0.09; allP < 0.05].Conclusion Mesenteric lymph drainage can alleviate acute lung injury in rats with bowel repletion, and its mechanism may be related to the reduction of the expressions of TLR4 mRNA and p38MAPK mRNA and the release of TNF-α and IL-6 in lung tissues.