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OBJECTIVE To investigate the improvement effects and mechanism of scutellarin （Scu） on neuroinflammation in rats with traumatic brain injury （TBI）. METHODS The modified Feeney method was applied to construct TBI rat model. The rats were randomly grouped into TBI group，Scu low-dose group （40 mg/kg），Scu high-dose group （80 mg/kg），cyclic guanylate- adenylate synthase （cGAS） inhibitor group （cGAS inhibitor RU.521，450 μg/kg），with 24 rats in each group. Other 24 rats were included in the sham operation group. The modified neurological deficit score （mNSS） method was applied to assess the neurological function of rats； the brain water content of rats was measured by dry/wet specific gravity method； hematoxylin-eosin and TdT-mediated dUTP nick-end labeling staining were applied to observe the pathological changes and apoptosis of brain tissue in rats； the levels of interferon-β （IFN-β），CXC chemokine ligand-10 （CXCL10），tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in rat brain tissue were detected by enzyme-linked immunosorbent assay； Western blot method was applied to detect the expression of cGAS/interferon gene stimulating protein （STING） signal pathway-related proteins in brain tissue of rats. RESULTS Compared with the sham operation group，the mNSS，brain water content，apoptosis rate，the contents of IFN-β，CXCL10，TNF-α and IL-6，and the relative expressions of cGAS and STING proteins in TBI group increased significantly （P＜0.05）； there were edema，bleeding and pathological damage to neurons in the brain tissue. Compared with TBI group，the above indicators and pathological changes of rats in administration groups were improved significantly （P＜0.05），and the effect of Scu was in a dose- dependent manner （P＜0.05）； however，there was no statistically obvious difference in the above indicators between the Scu high- dose group and the cGAS inhibitor group （P＞0.05）. CONCLUSIONS Scu may alleviate neuroinflammation，reduce brain tissue damage and apoptosis，and promote the recovery of neural function in TBI rats by inhibiting the activation of cGAS/STING signaling pathway.
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Objective:To investigate the effect of neutrophils on T lymphocyte function in septic mice and the role of CD80/cytotoxic T lymphocyte antigen-4 (CTLA-4) signaling pathway in this modulated effects.Methods:① In vivo experiment: 6-8 weeks old male C57BL/6 mice were divided into sham operation group (Sham group, n = 20), Sham+CTLA-4 antibody treatment group (Sham+aCTLA-4 group, n = 20), cecal ligation and perforation (CLP) induced sepsis model group (CLP group, n = 30) and CLP+CTLA-4 antibody treatment group (CLP+aCTLA-4 group, n = 30) according to the random number table. CLP was used to reproduce mouse sepsis model. The mice in the Sham group were treated identically but their cecums were neither punctured nor ligated. In CTLA-4 antibody treatment groups, 50 μg CTLA-4 antibody was injected intraperitoneally 6 hours and 24 hours after the operation. Forty-eight hours after operation, 6 mice in Sham group and Sham+aCTLA-4 group, 14 mice in CLP group and CLP+aCTLA-4 group were randomly selected to detect the expression of CD69 in spleen. At the same time, spleen, bone marrow and peripheral blood were collected, and the expression of CD80 on neutrophils was detected by flow cytometry. The expression of CTLA-4 on the surface of T lymphocytes in spleen was detected by immunofluorescence and flow cytometry. The remaining mice in each group were used to observe the 96-hour survival after operation.② In vitro experiment 1: neutrophils were extracted from bone marrow of healthy mice and stimulated with LPS (1 mg/L) for 4, 8 and 12 hours respectively. The control group was added with the same amount of phosphate buffered saline (PBS) at each time point, and the expression of CD80 was detected at each time point.③ In vitro experiment 2: splenic T lymphocytes of healthy mice were extracted and divided into PBS control group, LPS group (final concentration of LPS 1 mg/L), neutrophil group and neutrophil+LPS group. In the latter two groups, the co-culture model of neutrophils and T lymphocytes was established, and then the corresponding treatment was given to detect the expression of CTLA-4 on the surface of T lymphocytes. With the above four groups as controls, CTLA-4 antibody treatment groups (final concentration of CTLA-4 antibody 50 mg/L) were set up respectively. After 48 hours, the level of interleukin-2 (IL-2) in the cell supernatant was detected by enzyme linked immunosorbent assay (ELISA). Results:① Results of in vivo experiment: compared with Sham group, the expression of CD80 on neutrophils in spleen, bone marrow and peripheral blood was significantly up-regulated, while the expression of CTLA-4 on the surface of T lymphocytes was significantly increased [(9.98±0.84)% vs. (3.48±0.64)%, P < 0.05]. It suggested that neutrophils may affect T lymphocytes function through CD80/CTLA-4 pathway in sepsis. Compared with CLP group, CTLA-4 antibody could significantly improve the 96-hour cumulative survival rate of CLP mice (56.25% vs. 18.75%, P < 0.05), and increase the expression of CD69 on the surface of T lymphocytes. It suggested that CTLA-4 antibodies might increase T lymphocytes activation in sepsis and improve survival. ② Results of in vitro experiment: with the prolongation of LPS stimulation, the expression of CD80 on neutrophils gradually increased in time-dependent manner as compared with PBS control group [4 hours: (6.35±0.40)% vs. (3.41±0.40)%, 8 hours: (8.57±0.64)% vs. (3.09±0.27)%, 12 hours: (19.83±1.06)% vs. (5.16±0.36)%, all P < 0.05]. Compared with PBS control group, the expression of CTLA-4 on CD4 +/CD8 + T lymphocytes was not significantly affected by LPS stimulation alone, but CTLA-4 was increased after co-culture with neutrophils [CD4 +: (4.92±0.30)% vs. (3.33±0.25)%, CD8 +: (4.26±0.21)% vs. (2.53±0.66)%, both P < 0.05], and the increased trend of CTLA-4 was more obvious after co-culture with LPS-stimulated neutrophils [CD4 +: (6.34±0.50)% vs. (3.33±0.25)%, CD8 +: (6.21±0.41)% vs. (2.53±0.66)%, both P < 0.05]. In the PBS control group and LPS group, CTLA-4 antibody had no significant effect on IL-2 secretion of T lymphocytes. Compared with PBS control group, co-culture with neutrophils could inhibit the secretion of IL-2 by T lymphocytes (ng/L: 1 938.00±68.45 vs. 2 547.00±218.00, P < 0.05), and the inhibitory effect of neutrophils stimulated by LPS was more obvious (ng/L: 1 073.00±34.39 vs. 2 547.00±218.00, P < 0.05). CTLA-4 antibodies could partially restore IL-2 secretion. In conclusion, after promoting the expression of CTLA-4 on the surface of T lymphocytes, neutrophils might mediate the inhibition of T lymphocytes function by reducing the production of IL-2. Conclusions:Neutrophils mediate T lymphocytes dysfunction in sepsis, and the CD80/CTLA-4 pathway plays an important role. The CTLA-4 antibody improves survival and T lymphocytes function in sepsis mice, which may be a new method of immunotherapy for sepsis.
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Objective:To investigate the effect of heparin-binding protein (HBP) on the damage of vascular permeability in early burn.Methods:① Clinical research: 12 patients with severe burns admitted to Suzhou Hospital of Nanjing Medical University from January 1st to August 30th in 2019 were enrolled. Eight patients with severe trauma admitted to the same hospital during the same period were also enrolled as controls to explain the specificity of burn injury. Whole blood samples were obtained within 0.5 hour after admission. The white blood cell count (WBC), absolute value and ratio of neutrophils, and serum HBP levels were measured. Serum samples of 12 patients with severe burn were collected within 9 days after admission, and enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of metabolism products of glycocalyx including syndecan-1 and hyaluronic acid (HA). The correlation between HBP and neutrophils ratio, syndecan-1 and HA were analyzed by linear correlation. ② Basic research: a 30% total body surface area (TBSA) Ⅲ° burn model of Sprague-Dawley (SD) rat aged 6-8 weeks was prepared. In low molecular weight heparin (LMWH) intervention group ( n = 5), 200 U/kg LMWH was injected subcutaneously immediately and every 2 hours after injury for 4 times in total; the burn group ( n = 5) was given the same amount of normal saline. No intervention was given to the normal control group ( n = 5). The peripheral venous blood was collected at 0, 2, 4, and 8 hours after injury, and the serum levels of HBP, syndecan-1 and HA were measured; the injury of glycocalyx on pulmonary vascular endothelial cells was observed under transmission electron microscope. Results:① Clinical research results: the WBC, neutrophils absolute value and ratio, and HBP levels were increased in 12 patients with severe burn and 8 patients with severe trauma. There was no significant difference in the WBC, absolute value and ratio of neutrophils between severe burn and severe trauma patients [WBC (×10 9/L): 14.5±6.1 vs. 10.8±3.6, the absolute value of neutrophils (×10 9/L): 12.0±5.9 vs. 9.0±4.0, the ratio of neutrophils: 0.81±0.10 vs. 0.79±0.14, all P > 0.05], but the HBP levels in the burn patients were significantly higher than those in the trauma patients (μg/L: 192.92±61.73 vs. 51.17±23.05, P < 0.01). Twelve patients with severe burns had a sharp increase in serum syndecan-1 and HA levels after burns, which continued to maintain high levels and peaked at the 9th day [syndecan-1 (μg/L): 16.02±0.39, HA (μg/L): 106.83±4.90]. The analysis showed that HBP was positively correlated with neutrophils ratio, syndecan-1 and HA in severe burn patients at the 1st day after admission ( r values were 0.805, 0.732 and 0.900, respectively, all P < 0.01). It indicated that the sharp increase of neutrophils after the burn released a lot of HBP, and the glycocalyx of the vascular endothelium was severely damaged. ② Basic research results: the levels of serum HBP, syndecan-1 and HA in the burn group were increased sharply as compared with the normal control group, and continued to increase with time, reaching a peak at 8 hours after burn. In the LMWH intervention group, the serum levels of HBP, syndecan-1 and HA were significantly lower than those in the burn group, and the difference was still statistically significant after 8 hours [HBP (μg/L): 6.47±0.25 vs. 12.48±0.08, syndecan-1 (μg/L): 19.06±1.48 vs. 25.92±3.34, HA (μg/L): 35.76±2.10 vs. 54.91±2.64, all P < 0.01]. The results of transmission electron microscopy showed that in the normal control group, the glycocalyx pulmonary vascular endothelial cells was continuous, evenly distributed and dense. The glycocalyx on pulmonary vascular endothelial cells of rats were significantly damaged and shed 2 hours after burn in the burn group, and no glycocalyx was observed at 8 hours. In the LMWH intervention group, the glycocalyx on pulmonary vascular endothelial cells was damaged and the phenomenon of shedding was significantly relieved, and the glycocalyx could be observed 8 hours after the injury. Conclusion:The massive exudation of body fluids and the significant increase of vascular permeability in patients in early burns may be related to the destruction of the glycocalyx on endothelial cells by HBP released from increased neutrophils.
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Objective:To study the anti-inflammatory effect of the ethanol extract of Coptis chinensis Franch.in vitro.Methods: An inflammatory cell model was established by stimulating the mouse peritoneal macrophages in vitro with lipopolysaccharide(LPS).LPS stimulated of RAW264.7 cells for a long time after administration of intervention.Effect of ethanol extract of Coptis chinensis Franch.on RAW264.7 cell growth activity was analyzed by MTT assay.The production of tumor necrosis factor-α(TNF-α),IL-1β,IL-6,NO,prostaglandin E2(PGE2) was determined by ELISA.The expression of mRNA of TNF-α,induced nitric oxide synthase(iNos) and HO-1 was detected by real-time fluorescent quantitative PCR(RT-PCR).Results: The ethanol extract of Coptis chinensis had no inhibition effect on the scope of RAW 264.7 cells the scope of 5-80 mg/L.Each treatment group concentration of interleukin-6 (IL-6),interleukin-1β (IL-1β),TNF-α,NO,prostaglandin E2 (PGE2) content of LPS stimulation model group were significantly (P<0.01),and content was not related to concentration.Real-time quantitative (RT-PCR) showed,the concentration of each treatment group were significantly lower iNos,HO-1 and TNF-α mRNA expression (P<0.05,P<0.05,P<0.01),and content was not related to concentration.Conclusion: Coptis chinensis Franch.ethanol extract has anti-inflammatory effects in vitro,the mechanism may be related to inhibition of TNF-α,NO and other inflammatory factors and the impact of the activation of arachidonic acid (AA) metabolism.
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Objective To investigate the suppressive effect of exogenous carbon monoxide (CO) on abnormal platelet exocytosis and its possible molecular mechanism. Methods Venous blood was collected from healthy volunteers. Platelet-rich plasma (PRP) was isolated from the blood by differential centrifugation. The PRP was randomly divided into five groups by random number table, namely normal control group, lipopolysaccharide (LPS) group (challenged with 10 mg/L LPS), inactively exogenous carbon monoxide releasing molecule 2 (iCORM-2) group (given 10 mg/L LPS + 50 μmol/L iCORM-2 for intervention), exogenous carbon monoxide releasing molecule 2 (CORM-2) 10 μmol/L and 50 μmol/L groups (given 10 mg/L LPS + CORM-2 10 μmol/L or 50 μmol/L for intervention). After 30 minutes, enzyme linked immunosorbent assay (ELISA) was used to determine the platelet-derived growth factor BB (PDGF-BB) and matrix metalloproteinase 2 (MMP-2). Chemical fluorescein method was used to determine the platelet adenosine triphosphate (ATP). Flow cytometer was used to determine the expression of P-selectin. The expressions of Toll-like receptor 4 (TLR4), phosphorylation of protein kinase Cθ (PKCθ) and syntaxin binding protein 1 (STXBP-1) were determined by Western Bolt. The soluble N-ethylmaleimide-sensitive factor-attachment protein receptors (SNAREs) complex formation [syntaxin 2-synaptosomal-associated protein 23-vesicle associated membrane protein 8 (STX2-SNAP23-VAMP8)] mediated by STXBP-1 was determined by immunoprecipitation. Results ① Compared with normal control group, the platelet release of PDGF-BB, MMP-2 and ATP was significantly increased after LPS challenge, and the P-selectin expression of platelet was also obviously up-regulated [PDGF-BB (μg/L): 127.53±1.78 vs. 94.35±5.84, MMP-2 (ng/L): 51.87±9.20 vs. 35.83±3.17, ATP (μmol/L): 1.288±0.056 vs. 0.975±0.010, P-selectin: (3.93±0.19)% vs. (0.44±0.10)%, all P < 0.05]. The increases in platelet release of PDGF-BB, MMP-2 and ATP were suppressed by 10 μmol/L or 50 μmol/L CORM-2 administration, as well as high-expression of P-selectin in a dose-dependent manner [PDGF-BB (μg/L): 114.68±1.35, 97.08±6.14 vs. 127.53±1.78, MMP-2 (ng/L): 32.67±8.00, 24.63±1.63 vs. 51.87±9.20, ATP (μmol/L): 0.999±0.015, 0.965±0.008 vs. 1.288±0.056, P-selectin: (1.95±0.27)%, (0.94±0.11)% vs. (3.93±0.19)%, all P < 0.05]. ② Compared with normal control group, LPS challenge resulted in a significant increase in the expression of TLR4 and the phosphorylation of PKCθ and STXBP-1 [TLR4 (gray value): 1.21±0.38 vs. 0.67±0.06, p-PKCθ (gray value): 1.36±0.20 vs. 0.44±0.03, p-STXBP-1 (gray value): 1.13±0.06 vs. 0.59±0.04, all P < 0.05]. The increases in above parameters were suppressed by 10 μmol/L or 50 μmol/L CORM-2 administration in a dose-dependent manner [TLR4 (gray value): 0.76±0.05, 0.65±0.04 vs. 1.21±0.38; p-PKCθ (gray value): 0.71±0.07, 0.47±0.10 vs. 1.36±0.20; p-STXBP-1 (gray value): 0.56±0.02, 0.48±0.01 vs. 1.13±0.06, all P < 0.05]. ③ Compared with normal control group, the SNAREs proteins in platelet that combined with STXBP-1, including STX2, SNAP23 and VAMP8, were obviously increased after LPS challenge [STX2 (gray value): 1.35±0.06 vs. 0.57±0.04, SNAP23 (gray value): 0.97±0.04 vs. 0.30±0.12, VAMP8 (gray value): 1.37±0.12 vs. 0.77±0.10, all P < 0.05]. The increases in SNAREs complex formation were suppressed by 10 μmol/L or 50 μmol/L CORM-2 administration in a dose-dependent manner [STX2 (gray value): 0.77±0.02, 0.39±0.03 vs. 1.35±0.06, SNAP23 (gray value): 0.41±0.03, 0.22±0.08 vs. 0.97±0.04, VAMP8 (gray value): 0.85±0.07, 0.66±0.07 vs. 1.37±0.12, all P < 0.05]. There was no significant difference in the above mentioned parameters between iCORM-2 group and LPS group. Conclusions LPS-induced abnormal secretion of platelet was suppressed by CORM-2 administration. The mechanism may involve the TLR4/PKCθ/STXBP-1 signaling pathway activation and the SNAREs complex formation.
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<p><b>OBJECTIVE</b>To explore the effects of exogenous carbon monoxide-releasing molecule 2 (CORM-2) on formation of human neutrophil extracellular traps (NETs) stimulated by endotoxin/lipopolysaccharide (LPS) and its relevant mechanism.</p><p><b>METHODS</b>Venous blood samples were collected from a healthy adult volunteer to isolate neutrophils. The neutrophils were divided into normal control (NC) group, LPS group, LPS+ 10 μmol/L CORM-2 group, LPS+ 50 μmol/L CORM-2 group, and LPS+ inactive CORM-2 (iCORM-2) group according to the random number table. No treatment was given to the neutrophils in NC group. The neutrophils in LPS group underwent LPS stimulation (1 μL, 1 μg/mL). The neutrophils in LPS+ 10 μmol/L CORM-2 group, LPS+ 50 μmol/L CORM-2 group, and LPS+ iCORM-2 group underwent the same LPS stimulation as that in LPS group and treatment of 10 μmol/L CORM-2, 50 μmol/L CORM-2, and 50 μmol/L iCORM-2, respectively, with the volune of 1 μL. After conventional culture for 1 h, the number of NETs was determined with propidium iodide staining method; the early cell apoptosis rate was determined with flow cytometer; the generation level of reactive oxygen species (ROS) was assessed with dihydrogenrhodamine 123 fluorescent probe staining method (denoted as mean fluorescence intensity); the expression level of phosphorylated extracellular regulated kinase 1/2 (p-ERK1/2) was determined by Western blotting. The sample numbers of each group in the 4 experiments were all 5. Data were processed with one-way analysis of variance and SNK test.</p><p><b>RESULTS</b>(1) The numbers of NETs per 400-time visual field in cells of LPS and LPS+ iCORM-2 groups were close to the number in NC group (with P values above 0.05). The number of NETs per 400-time visual field was significantly larger in cells of LPS+ 10 μmol/L CORM-2 and LPS+ 50 μmol/L CORM-2 groups than in NC and LPS groups (with P values below 0.05). The number of NETs per 400-time visual field in cells of LPS+ iCORM-2 group was close to that of LPS group (P>0.05). (2) The early cell apoptosis rate was significantly increased in LPS, LPS+ 10 μmol/L CORM-2, LPS+ 50 μmol/L CORM-2, and LPS+ iCORM-2 groups than in NC group (with P values below 0.05). The early cell apoptosis rates in LPS+ 10 μmol/L CORM-2, LPS+ 50 μmol/L CORM-2, and LPS+ iCORM-2 groups were close to the rate in LPS group (with P values above 0.05). (3) The generation level of ROS was significantly higher in cells of LPS, LPS+ 10 μmol/L CORM-2, and LPS+ iCORM-2 groups than in NC group (with P values below 0.05). The generation level of ROS in cells of LPS+ 50 μmol/L CORM-2 group was close to that of NC group (P>0.05). The generation level of ROS was lower in cells of LPS+ 10 μmol/L CORM-2 and LPS+ 50 μmol/L CORM-2 groups than in LPS group (with P values below 0.05), while the generation level of ROS in cells of LPS+ iCORM-2 group was close to that of LPS group (P>0.05). (4) The expression levels of p-ERK1/2 in cells of LPS and LPS+ iCORM-2 groups (respectively 0.0311±0.001 and 0.0309±0.0018) were close to the level in NC group (0.0304±0.0046, with P values above 0.05). The expression level of p-ERK1/2 was significantly higher in cells of LPS+ 10 μmol/L CORM-2 and LPS+ 50 μmol/L CORM-2 groups (respectively 0.7891±0.0201 and 1.2970±0.0056) than in NC group (with P values below 0.05). The expression level of p-ERK1/2 was significantly higher in cells of LPS+ 10 μmol/L CORM-2 and LPS+ 50 μmol/L CORM-2 groups than in LPS group (with P values below 0.05). The expression level of p-ERK1/2 in cells of LPS+ iCORM-2 group was close to that of LPS group (P>0.05).</p><p><b>CONCLUSIONS</b>CORM-2 can obviously increase the production of NETs in LPS-induced neutrophils, and it might be attributable to the promotion of inhibition of ROS generation and phosphorylation of ERK1/2.</p>
Subject(s)
Humans , Apoptosis , Carbon Monoxide , Metabolism , Extracellular Traps , Lipopolysaccharides , Pharmacology , Organometallic Compounds , Pharmacology , PhosphorylationABSTRACT
Objective To determine the inhibitory effect and mechanism of exogenous carbon monoxide against excessive neutrophil infiltration in liver and lung tissues during sepsis.Methods Thirty-two mice were subjected to sham operation (sham group),cecal ligation and perforation (CLP) group,CLP with 8 mg/kg of exogenous carbon monoxide releasing molecule Ⅱ (CORM-2) (CORM-2 group),and CLP with 8 mg/kg of inactive variants of CORM-2 (iCORM-2) (iCORM-2 group) according to the random number table,with 8 mice per group.Liver and lung tissues were collected at 24 hours after surgery to examine the pathologic changes,myeloperoxidase (MPO) activity and malonaldehyde (MDA) content.Another 60 mice were enrolled into the same 4 groups with 15 mice per group and were tested for 72-hour survival rate.Bone marrow neutrophils were isolated and divided into normal control group,1 μg/ml lipopolysaccharide (LPS) group,1 μg/ml LPS plus 10 μmol/L CORM-2 group (low dose group),1 μg/ml LPS plus 50 μmol/L CORM-2 group (high dose group),1 μg/ml LPS plus 50 μmol/L iCORM-2 group (iCORM-2 group).Under the agarose chemotaxis,qPCR and immunofluorescence detection of formyl peptide receptor 1 (FPR1) were performed.Results CLP group presented enhanced activity of MPO [liver:(9.1 ± 1.1) U/g,lung:(16.3 ± 2.8) U/g],increased MDA content [liver:(76.5 ±11.3) nmol/mg,lung:(32.4 ± 10.3) nmol/mg] and 72-hour survival rate of 20％ as compared with the sham group (all P ＜ 0.05).CORM-2 group showed inhibited activity of MPO [liver:(5.2 ± 0.8) U/g,lung:(7.5 ± 2.4) U/g],increased MDA content [liver:(46.7 ± 6.1) nmol/mg,lung:(23.8 ±7.3) nmol/mg] and 72-hour survival rate of 67％ as compared with the sham group (all P ＜ 0.05).LPS enhanced neutrophil migration (61.3 ± 7.1) (P ＜ 0.05) and expression of FPR1 which was enriched in the membrane.Meanwhile,neutrophil migration was significantly inhibited in a dose-dependent of CORM-2 (low dose group:43.3 ±6.1,high-dose group:23.3 ±5.9) (P＜0.05).Conclusions Exogenous carbon monoxide is effective to inhibit the excessive neutrophil infiltration,attenuate oxidative stress or pathological injury,and improve the survival from sepsis.The mechanism is associated with the down-regulation of FPR1,inhibition of FPR1 enrichment in the membrane,and decreased neutrophil migration.