Opening of ATP-sensitive K+ channels protects H9c2 cardiac cells against high glucose-induced injury and inflammation by inhibiting TLR4/NF-κB pathway

AIM: To investigate whether the opening of ATP-sensitive K⁺(K_ATP) channels protects H9c2 cardiac cells against high glucose(HG)-induced injury and inflammation by inhibiting the Toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB) pathway. METHODS: The protein levels of TLR4 and NF-κB p65 were determined by Western blot. The levels of interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) were detected by ELISA. The cell viability was measured by CCK-8 assay. Mitochondrial membrane potential(MMP) was examined by rhodamine 123(Rh 123) staining followed by photofluorography. The intracellular levels of reactive oxygen species(ROS) were detected by 2', 7'-dichlorfluorescein- diacetate(DCFH-DA) staining followed by photofluorography. The number of apoptotic cells was observed by Hoechst 33258 nuclear staining followed by photofluorography. RESULTS: After the H9c2 cardiac cells were treated with HG(35 mmol/L glucose) for 24 h, the protein levels of TLR4 and phosphorylated NF-κB p65(p-NF-κB p65) were significantly increased. Pretreatment of the cells with 100 μmol/L diazoxide(DZ, a K_ATP channel opener) for 30 min before exposure to HG considerably blocked the up-regulation of the TLR4 and p-NF-κB protein levels induced by HG. Moreover, co-treatment of the cells with 30 μmol/L TAK-242(an inhibitor of TLR4) obviously inhibited the HG-induced up-regulation of the p-NF-κB p65 protein level. On the other hand, pretreatment of the cells with 100 μmol/L DZ had a clear myocardial protection effect, which attenuated the HG-induced cytotoxicity, inflammatory response, mitochondrial damage, oxidative stress and apoptosis, evidenced by an increase in the cell viability, and decreases in the levels of IL-1β and TNF-α, MMP loss, ROS generation and the number of apoptotic cells. Similarly, co-treatment of H9c2 cardiac cells with 30 μmol/L TAK-242 or 100 μmol/L PDTC(an inhibitor of NF-κB) and HG for 24 h also obviously reduced the above injuries and inflammation induced by HG.CONCLUSION: The opening of K_ATP channels protects H9c2 cardiac cells against HG-induced injury and inflammation by inhibiting the TLR4/NF-κB pathway.     

Role of interleukin-1β in spinal LTP in rats with neuropathic pain

AIM: To investigate the role of interleukin-1β (IL-1β) in the long-term potentiation (LTP) of C-fiber-evoked field potentials in rats with neuropathic pain. METHODS: The rat model of neuropathic pain was produced by spared nerve injury (SNI) of sciatic nerve or the method of lumbar 5 ventral root transection (L5 VRT). The effect of exogenous IL-1β on C-fiber-evoked field potentials of spinal dorsal horn was tested in both intact rats and the rats with neuropathic pain. The roles of p38 MAPK and NF-κB in the process were also evaluated. RESULTS: IL-1β at concentration of 500 μg/L affected neither basal synaptic transmission mediated by C-fiber nor spinal LTP induced by high frequency stimulation in intact rats. However, low concentration (5 μg/L) of IL-1β induced LTP of C-fiber-evoked field potentials in the rats with neuropathic pain. Pretreatment with either p38 MAPK inhibitor (SB203580) or NF-κB inhibitor (PDTC) completely blocked LTP induced by IL-1β. CONCLUSION: Exogeneous IL-1β might induce spinal LTP of C-fiber-evoked field potentials in the rats with neuropathic pain. p38 MAPK and NF-κB may be involved in the process.     

Nontypeable haemophilus influenzae induces IL-8 expression in alveolar epithelial cells in a p38 MAPK and NF-κB dependent manner

AIM:To investigate the key molecular mechanism of inflammatory response in alveolar epithelial cells induced by nontypeable haemophilus influenzae (NTHi). METHODS: A549 cells were co-cultured with NTHi (multiplicity of infection, MOI: 10) and harvested 15 min and 30 min after stimulation. The phosphorylation of p38 mitogen activated protein kinase (p38 MAPK) in A549 cells was detected by Western blotting. The intracellular expression of nuclear factor-κB (NF-κB) p65 was examined by flow cytometry 4 h after stimulation. A549 cells were preincubated with p38 inhibitor (SB203580) or NF-κB inhibitor (PDTC) for 1 h and then stimulated with NTHi for 24 h. The level of interleukin 8 (IL-8) in the supernatants was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: The phosphorylation of p38 MAPK was rapidly induced by NTHi stimulation. The expression of NF-κB p65 in A549 cells after NTHi stimulation was significantly up-regulated compared with control group (P<0.05). The level of IL-8 in the supernatants was increased 24 h after bacterial stimulation compared with control group (P<0.05). Blockage of p38 MAPK or NF-κB remarkably decreased IL-8 secretion in A549 cells (P<0.05). CONCLUSION:NTHi induces inflammatory response in alveolar epithelial cells in a p38 MAPK and NF-κB dependent manner.     

Role of p38 MAPK signaling pathway in inflammatory effects on cerulein-induced pancreatic cells

AIM: To investigate the effect of p38 MAPK signal pathway on cerulein-treated pancreatic acinar AR42J cells.METHODS: AR42J cells were divided into control group, cerulein group (treated with 10^-8 mol/L of cerulein), and SB203580 group (treated with 10 μmol/L of SB203580 and 10^-8mol/L of cerulein).The cells were harvested 3 h after treatment.Secretion rate of amylase was measured.The translocation of p-p38 MAPK to nuclei was imaged by immunofluorescence.The protein expression levels of p-p38 MAPK and TNF-α were detected by Western blotting.The activation of NF-κB was measured by electrophoretic mobility assay.RESULTS: Compared with control group, cerulein resulted in increases in the secretion rate of amylase and protein level of TNF-α (P<0.01), as well as the expression levels of p-p38 MAPK and NF-κB (P<0.01).Cerulein induced nuclear translocation of p-p38 MAPK.Compared with cerulein group, the secretion rate of amylase and protein level of TNF-α in SB203580 group decreased significantly (P<0.01).The expression of p-p38 MAPK and NF-κB also decreased greatly (P<0.05).Nuclear translocation of p-p38 MAPK was inhibited by SB203580.CONCLUSION: The p38 MAPK pathway involves in cerulein-induced pancreatic inflammatory response via regulating NF-κB.     

Role of TLR4-TRPC6 in LPS-induced NF-κB P65 expression and nuclear translocation in airway epithelial 16HBE cells

AIM: To investigate the role of Toll-like receptor 4 (TLR4) and transient receptor potential channel 6 (TRPC6) signaling pathway in lipopolysaccharide (LPS)-induced nuclear factor-κB (NF-κB) P65 expression and nuclear translocation in airway epithelial cells (16HBE) for supplementing the mechanism for airway inflammation. METHODS: After stimulating the 16HBE cells with LPS at 1 mg/L for 0, 0.5, 2, 6, 12 and 24 h, the expression of NF-κB P65 at mRNA and protein levels in the 16HBE cells were determined by RT-PCR and Western blot respectively, and the nuclear translocation of NF-κB P65 was detected by immunocytochemical staining method. The effects of TLR4 inhibitor CLI-095 at 5 μmol/L and TRPC6 agonist Hyp9 at 10 μmol/L on LPS (1 mg/L)-induced NF-κB P65 expression and nuclear translocation in the 16HBE cells were determined by RT-PCR, Western blot and immunocytochemical staining. RESULTS: LPS increased the mRNA and protein expression of NF-κB P65 and nuclear translocation in the 16HBE cells(P<0.05). TLR4 inhibitor CLI-095 reduced the mRNA and protein expression of NF-κB P65 and nuclear translocation induced by LPS, while Hyp9 enhanced the mRNA and protein expression of NF-κB P65 and nuclear translocation induced by LPS in the 16HBE cells(P<0.05). CONCLUSION: LPS induces the expression and nuclear translocation of NF-κB P65 in the 16HBE cells via TLR4-TRPC6 signaling pathway.     

Effects of Jiedu-Qingfei mixture on NF-κB and p38 MAPK pathways in lung tissues of rats with Mycoplasma pneumoniae infection

AIM: To observe the therapeutic effect of Jiedu-Qingfei mixture on Mycoplasma pneumoniae (MP)-infected rat lung tissues and to explore its mechanism. METHODS: SD rats (n=40) were randomly divided into 4 groups:blank control group, model group, Jiedu-Qingfei group and positive control group, with 10 rats in each group. The rats in experimental groups were slowly dripped with 1×10⁹ CFU/L MP solution into their nostrils for 4 d. One rat in each group was sacrificed for MP nucleic acid detection at the second day after inoculation, and the other rats were given gavage therapy. The rats in blank control group and model group were intragastrically given the same volume of normal saline, the rats in Jiedu-Qingfei group were given 8 mL/kg Jiedu-Qingfei mixture daily for 4 weeks, and the rats in psoitive control group were given dexmethasone sodium phosphate (0.5 mg·kg^-1·d^-1). After the experiment, the rats were killed. The serum and bronchoalveolar lavage fluid (BALF) were collected for detecting the levels of interleukin-12 (IL-12), IL-13 and TNF-α by ELISA. The right lung tissues were used for pathological observation and HE staining, while the left lung tissues were used to detect the expression of NF-κB p50, I-κBα and p38 mitogen-activated protein kinase (p38 MAPK) at mRNA and protein levels. RESULTS: The results of MP nucleic acid detection showed that all the rats except blank control group were MP nucleic acid positive, indicating that the rat model of MP infection was successfully established. On the 1st day of the treatment, the pathological scores of the lung tissues in model group and Jiedu-Qingfei group were significantly higher than those in blank control group (P<0.05). After treatment, the pathological scores of the lung tissues in mo-del group were significantly higher than those in blank control group and Jiedu-Qingfei group. The levels of IL-12 in the serum and BALF in model group were significantly lower than those in blank control group after MP infection (P<0.05), while those after treatment with Jiedu-Qingfei mixture were significantly higher than those in model group (P<0.05). The levels of IL-13 and TNF-α in the serum and BALF of MP-infected rats were increased significantly, while those after treatment with Jiedu-Qingfei mixture were significantly lower than those in model group (P<0.05). The mRNA expression levels of NF-κB p50 and p38 MAPK in model group were increased significantly (P<0.01). After treatment, the mRNA expression levels of NF-κB p50 and p38 MAPK were decreased significantly compared with model group (P<0.01). The mRNA expression level of I-κBα in model group was significantly lower than that in control group. After treatment, the mRNA expression of I-κBα in Jiedu-Qingfei group was significantly higher than that in model group (P<0.05). The protein levels of NF-κB p50 and p38 MAPK in the lung tissues of model group were significantly higher than those of blank control group. After treatment, the protein expression of NF-κB p50 and p38 MAPK was decreased significantly. The protein level of I-κBα in model group was significantly lower than that in blank control group, and after treatment with Jiedu-Qingfei mixture, the protein expression level of I-κBα was increased significantly (P<0.05). CONCLUSION: Jiedu-Qingfei mixture may attenuate lung tissue inflammation caused by MP through NF-κB and p38 MAPK pathways.     

Hydrogen sulfide inhibits inflammatory responses induced by acute myocardial ischemia in isolated rat hearts

AIM：To investigate whether hydrogen sulfide (H2S) protects the hearts against inflammatory responses induced by acute myocardial ischemia in isolated rat hearts. METHODS：Rat acute myocardial ischemia injury was induced by ligation of the left anterior descending coronary artery for 4 h, and the normal perfusate was replaced with NaHS (5 μmol/L, 10 μmol/L and 20 μmol/L) perfusate accordingly in NaHS groups 2 h after ischemia. The changes of cardiac function in the myocardial ischemic injury rats were observed. The mRNA expression of TNF-α, IL-1β, IL-6, IL-10 and ICAM-1 was detected by real-time PCR. The protein level of nuclear factor-κB (NF-κB) in the myocardial tissues was detected by Western blotting. RESULTS：The cardiac function in ischemia group was lower than that in sham group (P<0.01). Compared with ischemia group, perfusion of NaHS resulted in the improvement of the cardiac function (P<0.05 or P<0.01). Compared with sham group, the mRNA expression of TNF-α, IL-1β, IL-6 and ICAM-1 in the cardiac tissues was significantly increased, and the mRNA expression of IL-10 in the cardiac tissues was significantly decreased in ischemia group (P<0.01). Compared with ischemia group, the perfusion of NaHS significantly decreased the mRNA expression of TNF-α, IL-1β, IL-6 and ICAM-1 (P<0.05 or P<0.01). The perfusion of NaHS at concentrations of 10 μmol/L and 20 μmol/L significantly increased the mRNA expression of IL-10 (P<0.01). The protein level of NF-κB in ischemia group was markedly higher than that in sham group (P<0.01). Compared with ischemia group, the perfusion of NaHS at concentrations of 10 μmol/L and 20 μmol/L significantly decreased the expression of NF-κB (P<0.05 or P<0.01). CONCLUSION：H2S protects the hearts against acute ischemia injury through inhibition of NF-κB activation and subsequent down-regulation of NF-κB-dependent inflammatory gene expression.     

Effect of TRPV1 activation on lipopolysaccharide-induced lung inflammatory injury in mice

AIM:To investigate the effects of transient receptor potential cation channel subfamily V member 1 (TRPV1) activation by capsaicin on the inflammation and its underlying mechanisms in lipopolysaccharide (LPS)-induced lung injury in mice. METHODS:A total of 108 specific pathogen-free male ICR mice were randomly divided into 6 groups: normal control group, capsaicin (CAP) control group, capsazepine (CAPZ) control group, endotoxemia group, CAP treatment group and CAPZ treatment group. LPS was intraperitoneally injected 30 min after the subcutaneous injection of CAP or CAPZ. After modeling, the levels of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), IL-10, substance P (SP) and calcitonin gene-related peptide (CGRP) in the lung were measured by ELISA. The expression of Toll-like receptor 4 (TLR4) and nuclear factor κB (NF-κB) in the lung tissue was assessed by Western blotting. The pathological changes of the lung tissue were observed under light microscope. RESULTS:The expression of TNF-α, IL-6, IL-10 and NF-κB in the lung tissues at 3 h, 8 h and 16 h was dramatically higher in endotoxemia group than that in normal control group. Compared with endotoxemia group, the levels of TNF-α, IL-6 and nuclear NF-κB in CAP treatment group at 3 h, 8 h and 16 h were obviously decreased, but the level of IL-10 was increased. The changes of the factors mentioned above in CAPZ treatment group were absolutely adverse to those in CAP treatment group. The levels of SP and CGRP were significantly higher in endotoxemia group and CAP control group than those in normal control group, but those in CAPZ control group were lower. Compared with endotoxemia group, SP and CGRP were markedly increased in CAP treatment group and were obviously decreased in CAPZ treatment group. The level of TLR4 in endotoxemia group was distinctly higher than that in normal control group at 3 h, 8 h and 16 h. However, as compared with endotoxemia group, the expression of TLR4 in CAP treatment group and CAPZ treatment group didn’t change much. At 8 h and 16 h after modeling, the degree of lung damage was also decreased in CAP treatment group as compared with endotoxemia group, while that in CAPZ treatment group was aggravated. CONCLUSION: TRPV1 activation obviously inhibits the increase in TNF-α, IL-6 and NF-κB in the lung tissue of endotoxemia mice, and promotes the increase in the anti-inflammatory factor IL-10, as well as the levels of SP and CGRP, but has no effect on the expression of TLR4.     

Hydrogen sulfide inhibits doxorubicin-induced inflammation and cytotoxicity in rat cardiomyocytes by modulating activation of NF-κB pathway

AIM：To investigate whether hydrogen sulfide (H2S) attenuates doxorubicin (DOX)-induced inflammation and cytotoxicity in rat cardiomyocytes (H9c2 cells) by modulating nuclear factor κB (NF-κB) pathway. METHODS：The expression of NF-κB p65 was measured by western blotting. The secretion levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor α (TNF-α) were tested by enzyme-linked immunosorbent assay (ELISA). Cell viability was detected by Cell Counting Kit-8 (CCK-8) assay. Hoechst 33258 nuclear staining was used to detect the morphological changes and number of apoptotic cells. RESULTS：Treatment of H9c2 cells with 5 μmol/L DOX significantly up-regulated the expression level of phosphorylated NF-κB p65 (p-p65), and induced inflammation and cytotoxicity, as evidenced by increases in secretion levels of IL-1β, IL-6 and TNF-α and number of apoptotic cells as well as a decrease in cell viability. Pretreatment of H9c2 cells with 400 μmol/L NaHS (a donor of H2S) for 30 min markedly depressed the up-regulation of p-p65 expression induced by DOX. In addition, NaHS pretreatment also reduced DOX-induced inflammatory response and injury, leading to decreases in IL-1β, IL-6 and TNF-α secretion and number of apoptotic cells as well as an increase in cell viability. Similar to the effect of NaHS, pretreatment with 100 μmol/L pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, also blocked DOX-induced cardiac inflammation and cytotoxicity. Co-administration of IL-1 receptor antagonist (IL-1Ra) and DOX reduced DOX-induced activation of NF-κB and cytotoxicity in H9c2 cells. CONCLUSION：During the DOX-induced cardiomyocyte inflammation, there is positive interaction between NF-κB pathway and IL-1β. H2S may protect cardiomyocytes against DOX-induced inflammatory response and cytotoxicity by inhibiting NF-κB pathway.     

Artemisinin attenuates intestinal epithelial barrier damage induced by LPS

AIM: To investigate the effect of artemisinin on lipopolysaccharide(LPS)-induced intestinal epithelial barrier damage in IEC-6 cells and its molecular mechanism. METHODS: Cultured IEC-6 cells were divided to 5 groups: control group, LPS(100 mg/L) group and LPS+Artemisinin(30, 50 and 100 μmol/L) groups. The cytotoxicity was detected by MTT assay. The releases of TNF-α, IL-1β and IL-6 in the IEC-6 cells were measured by ELISA. The transepithelial electrical resistance(TER) was detected by electrical resistance tester, and the horseradish peroxidase(HRP) flux permeability were analyzed by a microplate reader. The expression of tight junction proteins, ZO-1, claudin-1 and occludin, and the expression of TLR4/MyD88/NF-κB at mRNA and protein levels were determined by RT-qPCR and Western blot. RESULTS: Artemisinin alone(up to 100 μmol/L) or in combination with LPS(100 mg/L) was not toxic to IEC-6 cells. Compared with control group, the releases of TNF-α, IL-1β and IL-6 in the culture supernatant of IEC-6 cells significantly increased after treatment with LPS. The expression of TLR4/MyD88/NF-κB was activated by LPS. LPS down-regulated the protein expression of ZO-1, claudin-1 and occludin. However, artemisinin treatment decreased the releases of TNF-α, IL-1β and IL-6 in the culture supernatant of IEC-6 cells. The expression of TLR4/MyD88/NF-κB at mRNA and protein levels was gradually reduced after treatment with artemisinin. In addition, artemisinin upregulated the protein expression of ZO-1, claudin-1 and occludin significantly(P<0.01) in a dose-dependent manner. CONCLUSION: Artemisinin attenuates LPS-induced intestinal epithelial barrier damage by inhibiting TLR4/MyD88/NF-κB activation in the IEC-6 cells.     

Oxidized α1-antitrypsin induces IL-8 and MCP-1 production in HBE cells

AIM:To investigate the effect of oxidized α1-antitrypsin (Ox-AT) on interleukin 8 (IL-8) and monocyte chemotactic protein 1(MCP-1) production in cultured human bronchial epithelial (HBE) cells. METHODS:Plasma native α1-antitrypsin (N-AT) was purified from human plasma by 50% and 75% ammonium sulfate fractionation followed by glutathione and anion exchange chromatography. Ox-AT was prepared by incubating N-AT (0.5 g/L) with N-chlorosuccinimide in a 25-fold molar excess to N-AT in PBS at room temperature for 30 min. HBE cells were cultured in the presence of Ox-AT (0.5 g/L) for 4 h, 10 h and 24 h, and the levels of IL-8 and MCP-1 in the supernatant were assayed using respective DuoSet kits. The effect of NF-κB inhibitor Bay11-7082 on the inflammatory cytokine release induced by Ox-AT was also evaluated. RESULTS:Ox-AT concentration-dependently and time-dependently increased the production of IL-8 and MCP-1 in HBE cells. The concentrations of IL-8 and MCP-1 in HBE cells induced by 0.5 g/L Ox-AT at 4 h, 10 h and 24 h were significantly higher than those in blank control and N-AT groups. Ox-AT increased the activity of NF-κB in a dose-dependent manner. The proinflammatory effect of by Ox-AT was inhibited by NF-κB inhibitor Bay11-7082. CONCLUSION: Ox-AT is a strong proinflammatory factor for HBE cells. The mechanism is related to NF-κB signaling pathway activation.     

Mollugin inhibits viability and collagen synthesis of rat CFSC-2G cells

AIM: To investigate the effects of mollugin on the viability and collagen synthesis of rat hepatic stellate cell line CFSC-2G. METHODS: The activation of CFSC-2G cells was induced with low concentration (10 μmol/L) of hydrogen peroxide (H₂O₂) for 30 min in the experiment. The viability of the CFSC-2G cells after exposed to mollugin at different concentrations (0, 20, 40, 60 and 120 μmol/L) was detected by MTT assay. The mRNA and protein expression levels of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), nuclear factor-κB (NF-κB) p65, Bcl-2, Bcl-xL, Bax, and hepatic stellate cell activation markers α-smooth muscle actin (α-SMA) and collagen type I (Col Ⅰ) were detected by real-time PCR and Western blot. The phosphorylation level of p38 mitogen-activated protein kinase (p38 MAPK) was determined by Western blot. RESULTS: Mollugin significantly inhibited the viability and collagen synthesis of activated CSFC-2G cells induced by H₂O₂. The expression of Nrf2, HO-1 and Bax at mRNA and protein levels, and the phosphorylation level of p38 MAPK were promoted, while the levels of NF-κB p65, Bcl-2, Bcl-xL, α-SMA and ColⅠwere inhibited by mollugin (P<0.05). CONCLUSION: Mollugin may inhibit H₂O₂-induced viability and collagen synthesis of the CSFC-2G cells by activating Nrf2 and HO-1, and blocking the NF-κB p65 and Bcl-2 expression.     

Protective effect of dexmedetomidine-ulinastatin combination on lipopolysaccharide-induced acute lung injury in rats

AIM：To investigate the effects of dexmedetomidine-ulinastatin combination on acute lung injury induced by lipopolysaccharide (LPS) in rats. METHODS：Male Wistar rats were randomly divided into 5 groups: saline control group (NS group) was given saline (5 mL/kg, iv) alone; LPS group (L group) was given LPS (10 mg/kg, over 10 min); dexmedetomidine+LPS group (L+D group) was treated with the additional administration of dexmedetomidine (1 μg·kg -1·h -1) immediately after LPS injection; ulinastatin+LPS group (L+U group) was treated with the addi-tional administration of ulinastatin (50 000 U/kg, ip) immediately after LPS injection; dexmedetomidine+ulinastatin+LPS group (L+D+U group) received dexmedetomidine (1 μg·kg -1·h -1) and ulinastatin (50 000 U/kg) immediately after LPS injection. The animals were sacrificed at 6 h after LPS or NS administration. Partial pressure of arterial oxygen (PaO 2), pH and base excess (BE) were measured, and the lungs were removed for evaluation of histological characteristics and determining the concentrations of TNF-α, IL-1β, macrophage inflammatory protein 2 (MIP-2), malondialdehyde (MDA), nitric oxide (NO), prostaglandin E 2 (PGE 2) and myeloperoxidase (MPO) in lung tissues, lung wet/dry weight ratio (W/D), and albumin in brochoalveolar lavage fluid (BLAF). The pulmonary expression of nuclear factor kappa B (NF-κB) p65 was evaluated by Western blotting. RESULTS：Compared with NS group, PaO 2, pH and BE was lower in L group, which was increased by treatment with dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone. Compared with NS group, LPS induced marked lung histological injury, which was less pronounced in the animals treated with dexmedetomidine-ulinastatin combination but not dexmedetomidine or ulinastatin alone. The levels of IL-1β, IL-6, MIP-2, MDA, NO and PGE 2 in the lung tissues increased in L group compared with NS group, which were reduced by dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone. The MPO activity, MDA level and W/D increased in the lung tissues in L group compared with NS group, which was reduced by dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone. Compared with NS group, the albumin concentration in the BLAF increased, which was reduced by dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone. Compared with NS group, the expression of NF-κB p65 increased in L group, which was reduced by dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone.CONCLUSION：Dexmedetomidine-ulinastatin combination has a protective effect on LPS-induced acute lung injury in the rats.     

Influence of complement bypass-activation on IL-8 expression in endothelial cells

AIM:To study the induction of IL-8 expression by bypass-activated complement in human umbilical vein endothelial cells (HUVECs) and regulatory effect of nuclear factor-kappa B on the expression of IL-8. METHODS:In vitro, zymosan-activated human serum(ZAHS) directly challenged the HUVECs monolayers. Following techniques were used in the experiment: ① RIA for measurement of IL-8,ISH for measurement of their mRNA.② EMSA for measurement of nuclear factor-kappa B(NF-κB). RESULTS:①After HUVECs monolayers were stimulated with ZAHS, the level of IL-8 increased significantly at 4 h. ②The NF-κB activity began upregulated within 30 min after ZAHS stimulation, maximal NF-κB activity was observed at 120 min. Pretreatment of endothelial monolayers with PDTC (20 μmol/L) significantly inhibited the secretion of IL-8 (P＜0.05). CONCLUSION:Bypass-activated complement directly challenged HUVECs to secret IL-8. Cytoplasma to nuclear translocation of NF-κB was necessary for this response.     

Effects of SAHA on hippocampal TLR4/MYD88 signaling and neuronal apoptosis after seizure in developing rats

AIM: To investigate the effect of vorinostat(suberoylanilide hydroxamic acid, SAHA), a histone deacetylase inhibitor, on seizure-induced brain damage in developing rats and its mechanism. METHODS: Male Sprague-Dawley rats(n=32) were randomly divided into control group, pentylenetetrazole(PTZ) group, PTZ+10 mg/kg SAHA group and PTZ+50 mg/kg SAHA group. Intraperitoneal injection of PTZ was used to induce rat seizure. SAHA was injected intraperitoneally 2 h before PTZ injection. The rats in different seizure stages were counted and mean seizure score was analyzed at 30~60 min after PTZ injection. Hippocampal tissues were sampled at 24 h after seizures. The expression of TLR4, MYD88, NF-κB P65 and IL-1β at mRNA and protein levels was detected by RT-qPCR and Western blot, respectively. The pathological changes of the brain tissues were observed by HE staining. The apoptotic neurons were observed by TUNEL staining. RESULTS: The mRNA and protein levels of TLR4, MYD88, NF-κB P65 and IL-1β, the apoptosis of neurons, the inflammation reaction and mean seizure score significantly increased after PTZ treatment(P<0.05), and these effects were attenuated by treatment with SAHA. Compared with PTZ+10 mg/kg SAHA group, PTZ+50 mg/kg SAHA group showed more significant protective effect against seizure-induced brain damage. CONCLUSION: Histone deacetylase inhibitor SAHA suppresses seizure-induced TLR4/MYD88 signaling and reduces apoptosis of neurons, suggesting a protective effect against brain damage associated with seizure in developing rats.     

Hypoxia-inducible factor-1α attenuates myocardial inflammatory injury induced by ischemia and reperfusion in rats

AIM:To investigate the role of hypoxia-inducible factor-1α (HIF-1α) stable expression in myocardial inflammatory injury induced by ischemia and reperfusion (I/R) in rats. METHODS:Male Wistar rats were randomly divided into 4 groups:sham operation (sham) group, I/R group, HIF-1α stabilizer dimethyloxalyl glycine (DMOG)+I/R group and HIF-1α inhibitor YC-1+I/R group. The protein expression of myocardial Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) was determined by Western blot. The mRNA levels of interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), IL-6, TLR4 and NF-κB were detected by real-time PCR. The myeloperoxidase (MPO) activity in the myocardial tissues was measured. HE staining was used to observe the infiltration of inflammatory cells. RESULTS:HIF-1α decreased the infiltration of inflammatory cells, the MPO activity, and the mRNA levels of inflammatory factors IL-1β, IL-6 and TNF-α in the myocardial tissues. HIF-1α also reduced the expression of TLR4 and NF-κB at mRNA and protein levels (P<0.05). CONCLUSION:The stable expression of HIF-1α has an anti-inflammatory effect on the myocardial tissues after I/R injury in rats. The mechanism may be related to the inhibition of TLR4/NF-κB signaling pathway.     

Effects of IL-32γ on proliferation and cell cycle of rat vascular smooth muscle cells

AIM: To observe the effects of interleukin-32γ (IL-32γ)on the proliferation and cell cycle of rat vascular smooth muscle cells (VSMCs). METHODS: The VSMCs were isolated from the thoracic aorta of SD rats by the method of tissue-piece inoculation. The cells were cultured and treated with different concentrations of IL-32γ. The proliferation of the cells was examined by MTT assay. The cell cycles were analyzed by flow cytometry. The protein levels of NF-κB p65 and cyclin D1 were detected by Western blotting. The expression of proliferating cell nuclear antigen (PCNA)was examined by immunocytochemical staining. RESULTS: Administration of IL-32γ at the concentrations of 10~50 μg/L for 24~48 h significantly promoted the proliferation of VSMCs in a dose- and time-dependent manner. After stimulation with IL-32γ at the concentration of 50 μg/L for 24 h, the cell cycle transition from G₁ phase to S/G₂ phase was accelerated and the expression levels of NF-κB p65, cyclin D1 and PCNA increased as compared with those in control group. CONCLUSION: IL-32γ promotes the proliferation of rat VSMCs and accelerates the cell cycle transition via upregulating the expression of NF-κB p65 and cyclin D1.     

Effects of angiopoietin 4 on lipopolysaccharide-induced injury of human umbilical vein endothelial cells

AIM:To observe the effects of angiopoietin 4 (Ang-4) on lipopolysaccharide (LPS)-induced injury of human umbilical vein endothelial cells (HUVECs). METHODS:The EnVision immunohistochemical method was used to identify the HUVECs. After pre-treated with different doses of Ang-4 for 0.5 h, HUVECs was exposed to LPS at concentration of 10 mg/L for 24 h. The cell viability was evaluated by MTT assay. The content of tumor necrosis factor-alpha (TNF-α) in the supernatant and the concentrations of intracellular and supernatant von Willebrand factor (vWF) were detected by ELISA. The mRNA levels of Toll-like receptor 4 (TLR4), NF-κB p65 and TNF-α were determined by real-time PCR. RESULTS:Factor Ⅷ in the cytoplasm was positive in the HUVECs.Compared with normal group, LPS reduced the cell viability (P<0.01), and significantly increased the secretion of TNF-α and vWF (P<0.01). The mRNA expression of TLR4, NF-κB p65 and TNF-α also increased (P<0.01). Ang-4 at concentration of 100 μg/L enhanced the cell viability (P<0.01), reduced the content of vWF and TNF-α, and inhibited the LPS-induced increases in the mRNA levels of TLR4, NF-κB p65 and TNF-α (P<0.01). CONCLUSION: Ang-4 antagonizes LPS-induced damage in HUVECs by inhibiting TLR4-NF-κB p65-TNF-α signaling pathways.     

Angiotensin-(1-7)/Mas receptor axis protects cardiomyocytes against high glucose-induced injury by modulating nuclear factor-κB pathway

AIM: To study whether the angiotensin-(1-7)[Ang-(1-7)]/Mas receptor axis protects cardiomyocytes against high glucose(HG)-induced injury by inhibiting nuclear factor-κB(NF-κB) pathway. METHODS: The cell viability was measured by CCK-8 assay. The intracellular levels of reactive oxygen species(ROS) were detected by DCFH-DA staining. The number of apoptotic cells was tested by Hoechst 33258 nuclear staining. Mitochondrial membrane potential(MMP) was examined by JC-1 staining. The levels of NF-κB p65 subunit and cleaved caspase-3 protein were determined by Western blotting. RESULTS: Treatment of H9c2 cardiac cells with 35 mmol/L glucose(HG) for 30, 60, 90, 120 and 150 min significantly enhanced the levels of phosphorated(p) NF-κB p65, peaking at 60 min. Co-treatment of the cells with 1 μmol/L Ang-(1-7) and HG for 60 min attenuated the up-regulation of p-NF-κB p65 induced by HG. Co-treatment of the cells with Ang-(1-7) at concentrations of 0.1~30 μmol/L and HG for 24 h inhibited HG-induced cytotoxicity, evidenced by an increase in cell viability. On the other hand, 1 μmol/L Ang-(1-7) ameliorated HG-induced apoptosis, oxidative stress and mitochondrial damage, indicated by decreases in the number of apoptotic cells, cleaved caspase-3 level, ROS generation and MMP loss. However, the above cardioprotective effects of Ang-(1-7) were markedly blocked by A-779, an antagonist of Ang-(1-7) receptor(Mas receptor). Similarly, co-treatment of H9c2 cardiac cells with 100 μmol/L PDTC(an inhibitor of NF-κB) and HG for 24 h also obviously reduced the above injuries induced by HG. CONCLUSION: Ang-(1-7)/Mas receptor axis prevents the cardiomyocytes from the HG-induced injury by inhibiting NF-κB pathway.