2.Effects of VX765 on osteoarthritis and chondrocyte inflammation in rats.
Wanran HUANG ; Junxue TU ; Aiqing QIAO ; Chujun HE
Chinese Journal of Reparative and Reconstructive Surgery 2024;38(1):74-81
OBJECTIVE:
To investigate the effects and underlying mechanisms of VX765 on osteoarthritis (OA) and chondrocytes inflammation in rats.
METHODS:
Chondrocytes were isolated from the knee joints of 4-week-old Sprague Dawley (SD) rats. The third-generation cells were subjected to cell counting kit 8 (CCK-8) analysis to assess the impact of various concentrations (0, 1, 5, 10, 20, 50, 100 μmol/L) of VX765 on rat chondrocyte activity. An in vitro lipopolysaccharide (LPS) induced cell inflammation model was employed, dividing cells into control group, LPS group, VX765 concentration 1 group and VX765 concentration 2 group without obvious cytotoxicity. Western blot, real-time fluorescence quantitative PCR, and ELISA were conducted to measure the expression levels of inflammatory factors-transforming growth factor β 1 (TGF-β 1), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α). Additionally, Western blot and immunofluorescence staining were employed to assess the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1). Thirty-two SD rats were randomly assigned to sham surgery group (group A), OA group (group B), OA+VX765 (50 mg/kg) group (group C), and OA+VX765 (100 mg/kg) group (group D), with 8 rats in each group. Group A underwent a sham operation with a medial incision, while groups B to D underwent additional transverse incisions to the medial collateral ligament and anterior cruciate ligament, with removal of the medial meniscus. One week post-surgery, groups C and D were orally administered 50 mg/kg and 100 mg/kg VX765, respectively, while groups A and B received an equivalent volume of saline. Histopathological examination using HE and safranin-fast green staining was performed, and Mankin scoring was utilized for evaluation. Immunohistochemical staining technique was employed to analyze the expressions of matrix metalloproteinase 13 (MMP-13) and collagen type Ⅱ.
RESULTS:
The CCK-8 assay indicated a significant decrease in cell viability at VX765 concentrations exceeding 10 μmol/L ( P<0.05), so 4 μmol/L and 8 μmol/L VX765 without obvious cytotoxicity were selected for subsequent experiments. Following LPS induction, the expressions of TGF-β 1, IL-6, and TNF-α in cells significantly increased when compared with the control group ( P<0.05). However, intervention with 4 μmol/L and 8 μmol/L VX765 led to a significant decrease in expression compared to the LPS group ( P<0.05). Western blot and immunofluorescence staining demonstrated a significant upregulation of Nrf2 pathway-related molecules Nrf2 and HO-1 protein expressions by VX765 ( P<0.05), indicating Nrf2 pathway activation. Histopathological examination of rat knee joint tissues and immunohistochemical staining revealed that, compared to group B, treatment with VX765 in groups C and D improved joint structural damage in rat OA, alleviated inflammatory reactions, downregulated MMP-13 expression, and increased collagen type Ⅱ expression.
CONCLUSION
VX765 can improve rat OA and reduce chondrocyte inflammation, possibly through the activation of the Nrf2 pathway.
Rats
;
Animals
;
Chondrocytes/metabolism*
;
Matrix Metalloproteinase 13/metabolism*
;
Rats, Sprague-Dawley
;
Tumor Necrosis Factor-alpha/metabolism*
;
Collagen Type II/metabolism*
;
Interleukin-6
;
Lipopolysaccharides/pharmacology*
;
NF-E2-Related Factor 2/pharmacology*
;
Inflammation/drug therapy*
;
Osteoarthritis/metabolism*
;
Transforming Growth Factor beta1/metabolism*
;
Dipeptides
;
para-Aminobenzoates
3.Role and mechanism of macrophage-mediated osteoimmune in osteonecrosis of the femoral head.
Yushun WANG ; Jianrui ZHENG ; Yuhong LUO ; Lei CHEN ; Zhigang PENG ; Gensen YE ; Deli WANG ; Zhen TAN
Chinese Journal of Reparative and Reconstructive Surgery 2024;38(1):119-124
OBJECTIVE:
To summarize the research progress on the role of macrophage-mediated osteoimmune in osteonecrosis of the femoral head (ONFH) and its mechanisms.
METHODS:
Recent studies on the role and mechanism of macrophage-mediated osteoimmune in ONFH at home and abroad were extensively reviewed. The classification and function of macrophages were summarized, the osteoimmune regulation of macrophages on chronic inflammation in ONFH was summarized, and the pathophysiological mechanism of osteonecrosis was expounded from the perspective of osteoimmune, which provided new ideas for the treatment of ONFH.
RESULTS:
Macrophages are important immune cells involved in inflammatory response, which can differentiate into classically activated type (M1) and alternatively activated type (M2), and play specific functions to participate in and regulate the physiological and pathological processes of the body. Studies have shown that bone immune imbalance mediated by macrophages can cause local chronic inflammation and lead to the occurrence and development of ONFH. Therefore, regulating macrophage polarization is a potential ONFH treatment strategy. In chronic inflammatory microenvironment, inhibiting macrophage polarization to M1 can promote local inflammatory dissipation and effectively delay the progression of ONFH; regulating macrophage polarization to M2 can build a local osteoimmune microenvironment conducive to bone repair, which is helpful to necrotic tissue regeneration and repair to a certain extent.
CONCLUSION
At present, it has been confirmed that macrophage-mediated chronic inflammatory immune microenvironment is an important mechanism for the occurrence and development of ONFH. It is necessary to study the subtypes of immune cells in ONFH, the interaction between immune cells and macrophages, and the interaction between various immune cells and macrophages, which is beneficial to the development of potential therapeutic methods for ONFH.
Humans
;
Femur Head/pathology*
;
Osteonecrosis/therapy*
;
Macrophages/pathology*
;
Inflammation
;
Femur Head Necrosis/pathology*
4.miR-185-5p alleviates the inflammatory response of acute gouty arthritis by inhibiting of IL-1β.
Nan HOU ; Xianghui MA ; Wei ZHOU ; Min YUAN ; Liming XU ; Huanxia SUN ; Yifan LIU ; Lining LIU ; Yanjun SHI ; Chunxian LI ; Yanfa FU
Chinese Journal of Cellular and Molecular Immunology 2024;40(1):51-57
Objective To investigate the relationship between interleukin-1β (IL-1β) and miR-185-5p in the process of joint injury in acute gouty arthritis (AGA). Methods The serum miR-185-5p levels of 89 AGA patients and 91 healthy volunteers were detected by real-time quantitative PCR. The correlation between miR-185-5p expression level and VAS score or IL-1β expression level was evaluated by Pearson correlation coefficient method. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of miR-185-5p in AGA. THP-1 cells were induced by sodium urate (MSU) to construct an in vitro acute gouty inflammatory cell model. After the expression level of miR-185-5p in THP-1 cells was upregulated or downregulated by transfection of miR-185-5p mimics or inhibitors in vitro, inflammatory cytokines of THP-1 cells, such as IL-1β, IL-8 and tumor necrosis factor α (TNF-α), were detected by ELISA. The luciferase reporter gene assay was used to determine the interaction between miR-185-5p and the 3'-UTR of IL-1β. Results Compared with the healthy control group, the expression level of serum miR-185-5p in AGA patients was significantly reduced. The level of serum miR-185-5p was negatively correlated with VAS score and IL-1β expression level. The area under the curve (AUC) was 0.905, the sensitivity was 80.17% and the specificity was 83.52%. Down-regulation of miR-185-5p significantly promoted the expression of IL-1β, IL-8 and tumor necrosis factor (TNF-α), while overexpression of miR-185-5p showed the opposite results. Luciferase reporter gene assay showed that IL-1β was the target gene of miR-185-5p, and miR-185-5p negatively regulated the expression of IL-1β. Conclusion miR-185-5p alleviates the inflammatory response in AGA by inhibiting IL-1β.
Humans
;
3' Untranslated Regions
;
Arthritis, Gouty/genetics*
;
Interleukin-1beta/genetics*
;
Interleukin-8
;
Luciferases
;
MicroRNAs/genetics*
;
Tumor Necrosis Factor-alpha
5.Predictive Value of Peripheral Blood Biomarkers in the Treatment of Lung Cancer Patients with Anti PD-1 Immunotherapy.
Shu SU ; Xin LV ; Liang QI ; Min WEI ; Baorui LIU ; Lifeng WANG
Chinese Journal of Lung Cancer 2024;26(12):901-909
BACKGROUND:
The application of programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) antibodies has greatly improved the clinical outcomes of lung cancer patients. Here, we retrospectively analyzed the efficacy of PD-1 antibody therapy in locally advanced non-surgical or metastatic lung cancer patients, and preliminarily explored the correlation between peripheral blood biomarkers and clinical responses.
METHODS:
We conducted a single center study that included 61 IIIA-IV lung cancer patients who received PD-1 antibody treatment from March 2020 to December 2021, and collected the medical record data on PD-1 antibody first-line or second-line treatment. The levels of multiple Th1 and Th2 cytokines in the patient's peripheral blood serum, as well as the phenotype of peripheral blood T cells, were detected and analyzed.
RESULTS:
All the patients completed at least 2 cycles of PD-1 monoclonal antibody treatment. Among them, 42 patients (68.9%) achieved partial response (PR); 7 patients (11.5%) had stable disease (SD); and 12 patients (19.7%) had progressive disease (PD). The levels of peripheral blood interferon gamma (IFN-γ) (P=0.023), tumor necrosis factor α (TNF-α) (P=0.007) and interleukin 5 (IL-5) (P=0.002) before treatment were higher in patients of the disease control rate (DCR) (PR+SD) group than in the PD group. In addition, the decrease in absolute peripheral blood lymphocyte count after PD-1 antibody treatment was associated with disease progression (P=0.023). Moreover, the levels of IL-5 (P=0.0027) and IL-10 (P=0.0208) in the blood serum after immunotherapy were significantly increased compared to baseline.
CONCLUSIONS
Peripheral blood serum IFN-γ, TNF-α and IL-5 in lung cancer patients have certain roles in predicting the clinical efficacy of anti-PD-1 therapy. The decrease in absolute peripheral blood lymphocyte count in lung cancer patients is related to disease progression, but large-scale prospective studies are needed to further elucidate the value of these biomarkers.
Humans
;
Lung Neoplasms/metabolism*
;
Interleukin-5/therapeutic use*
;
Tumor Necrosis Factor-alpha/therapeutic use*
;
Retrospective Studies
;
Programmed Cell Death 1 Receptor
;
Biomarkers
;
Immunotherapy
;
Disease Progression
;
B7-H1 Antigen
6.Protective Effects of Danmu Extract Syrup on Acute Lung Injury Induced by Lipopolysaccharide in Mice through Endothelial Barrier Repair.
Han XU ; Si-Cong XU ; Li-Yan LI ; Yu-Huang WU ; Yin-Feng TAN ; Long CHEN ; Pei LIU ; Chang-Fu LIANG ; Xiao-Ning HE ; Yong-Hui LI
Chinese journal of integrative medicine 2024;30(3):243-250
OBJECTIVE:
To investigate the effects of Danmu Extract Syrup (DMS) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and explore the mechanism.
METHODS:
Seventy-two male Balb/C mice were randomly divided into 6 groups according to a random number table (n=12), including control (normal saline), LPS (5 mg/kg), LPS+DMS 2.5 mL/kg, LPS+DMS 5 mL/kg, LPS+DMS 10 mL/kg, and LPS+Dexamethasone (DXM, 5 mg/kg) groups. After pretreatment with DMS and DXM, the ALI mice model was induced by LPS, and the bronchoalveolar lavage fluid (BALF) were collected to determine protein concentration, cell counts and inflammatory cytokines. The lung tissues of mice were stained with hematoxylin-eosin, and the wet/dry weight ratio (W/D) of lung tissue was calculated. The levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1 β in BALF of mice were detected by enzyme linked immunosorbent assay. The expression levels of Claudin-5, vascular endothelial (VE)-cadherin, vascular endothelial growth factor (VEGF), phospho-protein kinase B (p-Akt) and Akt were detected by Western blot analysis.
RESULTS:
DMS pre-treatment significantly ameliorated lung histopathological changes. Compared with the LPS group, the W/D ratio and protein contents in BALF were obviously reduced after DMS pretreatment (P<0.05 or P<0.01). The number of cells in BALF and myeloperoxidase (MPO) activity decreased significantly after DMS pretreatment (P<0.05 or P<0.01). DMS pre-treatment decreased the levels of TNF-α, IL-6 and IL-1 β (P<0.01). Meanwhile, DMS activated the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway and reversed the expressions of Claudin-5, VE-cadherin and VEGF (P<0.01).
CONCLUSIONS
DMS attenuated LPS-induced ALI in mice through repairing endothelial barrier. It might be a potential therapeutic drug for LPS-induced lung injury.
Mice
;
Male
;
Animals
;
Proto-Oncogene Proteins c-akt/metabolism*
;
Lipopolysaccharides
;
Phosphatidylinositol 3-Kinases/metabolism*
;
Interleukin-1beta/metabolism*
;
Vascular Endothelial Growth Factor A/metabolism*
;
Tumor Necrosis Factor-alpha/metabolism*
;
Claudin-5/metabolism*
;
Acute Lung Injury/chemically induced*
;
Lung/pathology*
;
Interleukin-6/metabolism*
;
Drugs, Chinese Herbal
7.Dermatophagoides farinae induces conjunctival epithelial cell damage to promote neutrophil migration and neutrophil extracellular traps formation.
Meili WU ; Ru YAN ; Wenjun ZHAO
Chinese Journal of Schistosomiasis Control 2023;35(3):271-278
OBJECTIVE:
To investigate the mechanisms underlying allergic conjunctivitis caused by conjunctival epithelial cell damage, neutrophil migration and neutrophil extracellular traps (NETs) formation induced by crude extracts of Dermatophagoides farinae mite (CDM).
METHODS:
Human conjunctival epithelial cells were stimulated with 500, 1 000, 2 000, 4 000 ng/mL, and the expression levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and IL-8 were detected using quantitative real-time PCR (qPCR) assay and enzyme-linked immunosorbent assay (ELISA). The culture supernatant of human conjunctival epithelial cells was collected and co-cultured with neutrophils. Neutrophil migration was measured using Transwell migration assay, and the expression of NETs markers myeloperoxidase (MPO) and citrullinated histone H3 (CitH3) was quantified using immunofluorescence staining. Neutrophils were stimulated with phorbol 12-myristate 13-acetate (PMA), and then NETs were collected for treatment of human conjunctival epithelial cells. Cell apoptosis was detected using flow cytometry, and the levels of IL-6, TNF-α, IFN-γ and IL-8 were measured in the cell culture supernatant using ELISA.
RESULTS:
Treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL up-regulated IL-6, TNF-α, IFN-γ and IL-8 expression in human conjunctival epithelial cells. Following treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL, the culture supernatant of human conjunctival epithelial cells promoted neutrophil migration and induced increases in the staining intensity of MPO and CitH3. In addition, increased NETs triggered the apoptosis of human conjunctival epithelial cells and IL-6, TNF-α, IFN-γ and IL-8 secretion in the culture supernatant of human conjunctival epithelial cells.
CONCLUSIONS
CDM induces human conjunctival epithelial cell damages, thereby promoting neutrophil migration and NETs formation, while the release of NETs further aggravates human conjunctival epithelial cell damages.
Animals
;
Humans
;
Extracellular Traps
;
Neutrophils
;
Interleukin-8/metabolism*
;
Dermatophagoides farinae
;
Interleukin-6/metabolism*
;
Tumor Necrosis Factor-alpha/metabolism*
;
Epithelial Cells
;
Interferon-gamma/metabolism*
;
Tetradecanoylphorbol Acetate/pharmacology*
8.Revealing the role of gut microbiota in immune regulation and organ damage in sepsis using 16s rRNA and untargeted metabolomics.
Ping ZHANG ; Lei YANG ; Yuzhen ZHUO ; Lingzhi CUI ; Qiaoying GAO ; Min ZHOU ; Lixiu GE ; Jiarui LI
Chinese Critical Care Medicine 2023;35(9):927-932
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.
Rats
;
Male
;
Animals
;
Tumor Necrosis Factor-alpha
;
RNA, Ribosomal, 16S
;
Gastrointestinal Microbiome
;
Interleukin-6
;
Rats, Wistar
;
Sepsis
9.Wedelolactone alleviates hyperoxia-induced acute lung injury by regulating ferroptosis.
Junya LIU ; Song QIN ; Banghai FENG ; Miao CHEN ; Hong MEI
Chinese Critical Care Medicine 2023;35(11):1177-1181
OBJECTIVE:
To study whether wedelolactone can reduce hyperoxia-induced acute lung injury (HALI) by regulating ferroptosis, and provide a basic theoretical basis for the drug treatment of HALI.
METHODS:
A total of 24 C57BL/6J mice were randomly divided into normal oxygen control group, HALI model group and wedelolactone pretreatment group, with 8 mice in each group. Mice in wedelolactone pretreatment group were treated with wedelolactone 50 mg/kg intraperitoneally for 6 hours, while the other two groups were not given with wedelolactone. After that, the HALI model was established by maintaining the content of carbon dioxide < 0.5% and oxygen > 90% in the molding chamber for 48 hours, and the normal oxygen control group was placed in indoor air. After modeling, the mice were sacrificed and lung tissues were collected. The lung histopathological changes were observed under light microscope and pathological scores were performed to calculate the ratio of lung wet/dry mass (W/D). The levels of tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-1β), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) in lung tissues of mice in each group were determined. The protein expression of glutathione peroxidase 4 (GPX4) in lung tissue was detected by Western blotting.
RESULTS:
Under light microscope, the alveolar structure of HALI model group was destroyed, and a large number of neutrophils infiltrated the alveolar and interstitial lung, and the interstitial lung was thickened. The pathological score of lung injury (score: 0.75±0.02 vs. 0.11±0.01) and the ratio of lung W/D (6.23±0.34 vs. 3.68±0.23) were significantly higher than those in the normal oxygen control group (both P < 0.05). Wedelolactone pretreated mice had clear alveolar cavity and lower neutrophil infiltration and interstitial thickness than HALI group. Pathological scores (score: 0.43±0.02 vs. 0.75±0.02) and W/D ratio (4.56±0.12 vs. 6.23±0.34) were significantly lower than HALI group (both P < 0.05). Compared with the normal oxygen control group, the levels of SOD (kU/g: 26.41±4.25 vs. 78.64±3.95) and GSH (mol/g: 4.51±0.33 vs. 12.53±1.25) in HALI group were significantly decreased, while the levels of MDA (mmol/g: 54.23±4.58 vs. 9.65±1.96), TNF-α (μg/L: 96.32±3.67 vs. 11.65±2.03), IL-6 (ng/L: 163.35±5.89 vs. 20.56±3.63) and IL-1β (μg/L: 72.34±4.64 vs. 15.64±2.47) were significantly increased, and the protein expression of GPX4 (GPX4/β-actin: 0.44±0.02 vs. 1.00±0.09) was significantly decreased (all P < 0.05). Compared with the HALI group, the levels of SOD (kU/g: 53.28±3.69 vs. 26.41±4.25) and GSH (mol/g: 6.73±0.97 vs. 12.53±1.25) were significantly higher in the wedelolactone pretreatment group, and the levels of MDA (mmol/g: 25.36±1.98 vs. 54.23±4.58), TNF-α (μg/L: 40.25±4.13 vs. 96.32±3.67), IL-6 (ng/L: 78.32±4.65 vs. 163.35±5.89), and IL-1β (μg/L: 30.65±3.65 vs. 72.34±4.64) were significantly lower (all P < 0.05), and protein expression of GPX4 was significantly higher (GPX4/β-actin: 0.68±0.04 vs. 0.44±0.02, P < 0.05).
CONCLUSIONS
Wedelolactone attenuates HALI injury by regulating ferroptosis.
Mice
;
Animals
;
Hyperoxia
;
Ferroptosis
;
Tumor Necrosis Factor-alpha
;
Interleukin-6
;
Actins
;
Mice, Inbred C57BL
;
Acute Lung Injury/drug therapy*
;
Lung
;
Oxygen
;
Superoxide Dismutase
10.Role of Nrf2/GPX4 mediated ferroptosis in intestinal injury in sepsis.
Tao MA ; Weiwei HUANG ; Zhihua LI ; Yi WANG ; Xiaoming GAO ; Xiangyou YU
Chinese Critical Care Medicine 2023;35(11):1188-1194
OBJECTIVE:
To investigate whether ferroptosis exists in sepsis induced intestinal injury, and to verify the association between ferroptosis in sepsis induced intestinal injury and intestinal inflammation and barrier function by stimulating and inhibiting the nuclear factor E2-related factor 2/glutathione peroxidase 4 (Nrf2/GPX4) pathway.
METHODS:
Forty-eight SPF grade male Sprague-Darvley (SD) rats with a body weight of 220-250 g were divided into sham operation group (Sham group), sepsis group (CLP group), sepsis+iron chelating agent deferoxamine (DFO) group (CLP+DFO group) and sepsis+ferroptosis inducer Erastin group (CLP+Erastin group) using a random number table method, with 12 rats in each group. The sepsis model was established by cecal ligation and puncture (CLP). The Sham group was only performed with abdominal opening and closing operations. After modeling, the CLP+DFO group received subcutaneous injection of 20 mg/kg of DFO, the CLP+Erastin group was intraperitoneally injected with 20 mg/kg of Erastin. Each group received subcutaneous injection of 50 mg/kg physiological saline for fluid resuscitation after surgery, and the survival status of the rats was observed 24 hours after surgery. At 24 hours after model establishment, 6 rats in each group were selected. First, live small intestine tissue was taken for observation of mitochondrial morphology in smooth muscle cells under transmission electron microscopy and determination of reactive oxygen species (ROS). Then, blood was collected from the abdominal aorta and euthanized. The remaining 6 rats were sacrificed after completing blood collection from the abdominal aorta, and then small intestine tissue was taken. Western blotting was used to detect the expression of intestinal injury markers such as Claudin-1 and ferroptosis related proteins GPX4 and Nrf2. Observe the pathological changes of small intestine tissue using hematoxylin-eosin (HE) staining and complete Chiu score; Detection of tumor necrosis factor-α (TNF-α), interleukins (IL-1β, IL-6) levels in serum using enzyme-linked immunosorbent assay (ELISA). The levels of serum iron ions (Fe3+), malondialdehyde (MDA), and D-lactate dehydrogenase (D-LDH) were measured.
RESULTS:
(1) Compared with the Sham group, the 24-hour survival rate of rats in the CLP group and CLP+Erastin group significantly decreased (66.7%, 50.0% vs. 100%, both P < 0.05), while there was no significant difference in the CLP+DFO group (83.3% vs. 100%, P = 0.25). (2) Western blotting results showed that compared with the Sham group, the expressions of GPX4 and Claudin-1 in the small intestine tissue of the CLP group, CLP+DFO group, and CLP+Erastin group decreased significantly, while the expression of Nrf2 increased significantly (GPX4/β-actin: 0.56±0.02, 1.03±0.01, 0.32±0.01 vs. 1.57±0.01, Claudin-1/β-actin: 0.60±0.04, 0.96±0.07, 0.41±0.01 vs. 1.40±0.01, Nrf2/β-actin: 0.88±0.02, 0.72±0.01, 1.14±0.01 vs. 0.43±0.02, all P < 0.05). Compared with the CLP group, the expressions of GPX4 and Claudin-1 were significantly increased in the CLP+DFO group, while the expression of Nrf2 was significantly reduced. In the CLP+Erastin group, the expressions of GPX4 and Claudin-1 further decreased, while the expression of Nrf2 further increased (all P < 0.05). (3) Under the light microscope, compared with the Sham group, the CLP group, CLP+DFO group, and CLP+Erastin group showed structural disorder in the small intestinal mucosa and submucosal tissue, significant infiltration of inflammatory cells, and destruction of glandular and villous structures. The Chui score was significantly higher (3.25±0.46, 2.00±0.82, 4.50±0.55 vs. 1.25±0.45, all P < 0.05). (4) Under transmission electron microscopy, compared with the Sham group, the mitochondria in the other three groups of small intestinal smooth muscle cells showed varying degrees of volume reduction, increased membrane density, and reduced or disappeared cristae. The CLP+Erastin group showed the most significant changes, while the CLP+DFO group showed only slight changes in mitochondrial morphology. (5) Compared to the Sham group, the CLP group, CLP+DFO group, and CLP+Erastin group had serum levels of TNF-α, IL-1β, IL-6, MDA, D-LDH, and ROS in small intestine tissue were significantly increased, while the serum Fe3+ content was significantly reduced [TNF-α (ng/L): 21.49±1.41, 17.24±1.00, 28.66±2.72 vs. 14.17±1.24; IL-1β (ng/L): 108.40±3.09, 43.19±8.75, 145.70±11.00 vs. 24.50±5.55; IL-6 (ng/L): 112.50±9.76, 45.90±6.52, 151.80±9.38 vs. 12.89±6.11; MDA (μmol/L): 5.61±0.49, 3.89±0.28, 8.56±1.17 vs. 1.86±0.41; D-LDH (kU/L): 39.39±3.22, 25.38±2.34, 53.29±10.53 vs. 10.79±0.52; ROS (fluorescence intensity): 90 712±6 436, 73 278±4 775, 110 913±9 287 vs. 54 318±2 226; Fe3+ (μmol/L): 22.19±1.34, 34.05±1.94, 12.99±1.08 vs. 51.74±11.07; all P < 0.05]. Compared with CLP group, the levels of TNF-α, IL-1β, IL-6, MDA, D-LDH and ROS in CLP+Erastin group were further increased, and the content of Fe3+ was further decreased, the CLP+DFO group was the opposite (all P < 0.05).
CONCLUSIONS
Ferroptosis exists in the intestinal injury of septic rats, and stimulating or inhibiting ferroptosis through the Nrf2/GPX4 pathway can effectively intervene in the inflammatory state and intestinal mechanical barrier of the body.
Rats
;
Male
;
Animals
;
NF-E2-Related Factor 2
;
Tumor Necrosis Factor-alpha
;
Ferroptosis
;
Reactive Oxygen Species
;
Actins
;
Claudin-1
;
Interleukin-6
;
Sepsis/metabolism*
;
Iron

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