Lipoxin A4 alleviates lung injury in sepsis rats through p38/MAPK signaling pathway

Study on the protective effect of berberine treatment on sepsis based on gut microbiota and metabolomic analysis

Introduction

Sepsis, an infection with multiorgan dysfunction, is a serious burden on human health. Berberine (BBR), a bioactive component, has a protective effect on sepsis and the effect may be related to gut microbiota. However, studies on the role of BBR with gut microbiota in sepsis are lacking. Therefore, this study investigated the ameliorative effects and the underlying mechanisms of BBR on cecal ligature and puncture (CLP) rats.

Methods

This study has observed the effect of BBR on pathological injury, Inflammation, intestinal barrier function, gut microbiota, and metabolite change in CLP rats by Hematoxylin-eosin staining, enzyme-linked immunosorbent assays, flow cytometry, 16S rDNA, and metabolomics analyses.

Results

The inhibition effects of BBR treatment on the histological damage of the lung, kidney, and ileum, the interleukin (IL)-1b, IL-6, IL-17A, and monocyte chemokine-1 levels in serum in CLP rats were proved. Also, the BBR inhibited the diamine-oxidase and fluorescein isothiocyanate-dextran 40 levels, suggesting it can improve intestinal barrier function disorders. The cluster of differentiation (CD) 4⁺, CD8⁺, and CD25⁺ Forkhead box protein P3 (Foxp3) + T lymphocytes in splenocytes were up-regulated by BBR, while the IL-17A+CD4+ cell level was decreased. The abundance of gut microbiota in CLP rats was significantly different from that of the sham and BBR treatment rats. The significantly changed metabolites in the serum mainly included carbohydrates, phenols, benzoic acids, alcohols, vitamins et al. Additionally, this study predicted that the biological mechanism of BBR to ameliorate sepsis involves glycolysis-, nucleotide-, and amino acid-related metabolic pathways.

Discussion

This study proved the strong correlation between the improvement effect of BBR on sepsis and gut microbiota and analyzed by metabolomics that gut microbiota may improve CLP rats through metabolites, providing a scientific basis for BBR to improve sepsis and a new direction for the study of the biological mechanism.

miR‑374a‑5p alleviates sepsis‑induced acute lung injury by targeting ZEB1 via the p38 MAPK pathway

The aim of the present study was to investigate the effects of microRNA (miR)-374a-5p on sepsis-induced acute lung injury (ALI) and the associated mechanism. Lipopolysaccharide (LPS)-induced human pulmonary microvascular endothelial cells (HPMVECs) were used to construct the cellular model of sepsis. A luciferase reporter assay was performed to confirm the association between miR-374a-5p and zinc finger E-box binding homeobox 1 (ZEB1). Reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to assess the relative expression of miR-374a-5p, ZEB1 and apoptosis-related proteins. Cell viability and apoptosis were determined by Cell Counting Kit-8 assay and flow cytometry, respectively. Enzyme-linked immunosorbent assays were used to evaluate inflammatory cytokines. The results revealed that miR-374a-5p was downregulated in sepsis patients and LPS-treated HPMVECs. Upregulation of miR-374a-5p alleviated LPS-triggered cell injury in HPMVECs, as evidenced by restoration of cell viability, and inhibition of apoptosis and the production of proinflammatory cytokines. In addition, ZEB1 was revealed to be a downstream target of miR-374a-5p, and overexpression of ZEB1 could reverse the anti-apoptotic and anti-inflammatory effects of miR-374a-5p on an LPS-induced sepsis cell model. Moreover, miR-374a-5p-induced protective effects involved the p38 MAPK signaling pathway. Collectively, miR-374a-5p exerted a protective role in sepsis-induced ALI by regulating the ZEB1-mediated p38 MAPK signaling pathway, providing a potential target for the diagnosis and treatment of sepsis.

Effects of propofol on inflammatory response and activation of p38 MAPK signaling pathway in rats with ventilator-induced lung injury

Purpose:

To investigate the effects of propofol on inflammatory response and activation of p38 mitogen-activated protein kinase (MAPK) signaling pathway in rats with ventilator-associated lung injury (VALI).

Methods:

Thirty-six Sprague Dawley (SD) rats were divided into control, VALI and VALI+propofol groups. The VALI group received the mechanical ventilation for 2 h. The VALI+propofol group received the mechanical ventilation for 2 h, which was accompanied by intravenous injection of propofol with dose of 8 mg·kg^-1·h^-1. At the end, the mean arterial pressure (MAP) and blood gas indexes were measured, and the lung wet/dry mass ratio (W/D) and biochemical indexes of lung tissue and bronchoalveolar lavage fluid (BALF) were determined.

Results:

Compared with VALI group, in VALI+propofol group the blood pH, partial pressure of oxygen, partial pressure of carbon dioxide and MAP were increased, the lung W/D, lung tissue myeloperoxidase activity and total protein concentration, white blood cell count, and tumor necrosis factor α, interleukin 1β and interleukin 6 levels in BALF were decreased, and the p-p38 MAPK protein expression level and phosphorylated p38 MAPK (p-p38 MAPK)/p38 MAPK ratio were decreased.

Conclusions:

Propofol treatment may alleviate the VALI in rats by reducing the inflammatory response and inhibiting the activation of p38 MAPK signaling pathway.

Protective effect of taurine on sepsis‑induced lung injury via inhibiting the p38/MAPK signaling pathway

Sepsis, a leading cause of acute lung injury (ALI), is characterized by an overwhelming systemic inflammatory response and widespread organ injury, particularly in the lungs. Taurine, an intracellular free amino acid, has been used for the treatment of various diseases, including lung injury; however, the underlying mechanisms are unclear. The present study aimed to investigate the protective effect of taurine on septic ALI and the underlying mechanism. A septic ALI model was established by performing cecal ligation and puncture (CLP) surgery on Sprague Dawley rats. Following successful model establishment, rats were treated with taurine. The results of hematoxylin and eosin, respiratory function detection, malondialdehyde level and superoxide dismutase activity determination and ELSIA demonstrated that taurine significantly alleviated lung injury, restored respiratory function, reduced oxidation and decreased the concentrations of inflammatory factors in CLP‑induced septic ALI model rats. In addition, compared with that in the ALI group, western blotting results indicated that taurine ameliorated lung epithelial injury by significantly increasing the expression levels of lung epithelial markers, E‑cadherin and occludin. The western blotting results demonstrated that, compared with the control group, the p38/MAPK and NF‑κB signaling pathways were significantly activated in CLP‑induced septic ALI model rats, but taurine significantly suppressed ALI‑mediated signaling pathway activation. To investigate the mechanism underlying taurine in the treatment of septic ALI, CLP‑induced septic ALI model rats were treated with an antagonist of the p38/MAPK signaling pathway (SB203580). The effects of SB203580 on CLP‑induced septic ALI model rats were similar to those of taurine. SB203580 significantly attenuated sepsis‑induced lung injury and increases in IL‑1β and TNF‑α concentrations in the lung tissue. In addition, SB203580 promoted restoration of the injured lung tissue and respiratory function in CLP‑induced septic ALI model rats. The western blotting results indicated that SB203580 significantly decreased the ratios of phosphorylated (p)‑p38/p38 and p‑p65/065, and increased the protein expression levels of E‑cadherin and occludin compared with those in the ALI group. In summary, the present study demonstrated that taurine alleviated sepsis‑induced lung injury, which was associated with suppression of the inflammatory response and oxidative stress via inhibiting the p38/MAPK signaling pathway. Therefore, the p38/MAPK signaling pathway may serve as a potential therapeutic target for the treatment of sepsis‑induced ALI.