Expression of calprotectin in rats with renal ischemia-reperfusion injury

AIM: To investigate the expression of calprotectin(CALP) in the rats with renal ischemia-reperfusion injury(IRI). METHODS: Male Sprague-Dawley rats were randomly divided into sham operation and IRI group(n=25 in each group). Blood samples and the kidneys were obtained at 6 h, 12 h, 24 h, 48 h and 72 h after reperfusion. The pathological changes of the kidneys were observed. The serum concentrations of blood urea nitrogen(BUN) and serum creatinine(SCr) were measured. The serum levels of CALP, tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) were detected by ELISA, and the expression of CALP, Toll-like receptor 4(TLR4) and NF-κB p65 in the renal tissues were determined by the methods of immunohistochemistry and Western blot. RESULTS: Different serial ischemia changes were observed in the renal tissues, mainly in the renal tubular epithelial cells and the mesenchyma, with the infiltration of inflammatory cells. The serum levels of BUN, SCr, CALP, TNF-α and IL-6 in IRI group were markedly increased as compared with sham group(P<0.05). The protein expression of CALP, TLR4 and NF-κB p65 in the renal tubular epithelial cells in IRI group was greatly enhanced in comparison with that in sham group(P<0.05). CONCLUSION: The serum concentrations of CALP, TNF-α and IL-6, and the protein expression levels of CALP, TLR4 and NF-κB p65 in the renal tissue are significantly increased in the rats with IRI, suggesting that calprotectin plays an important role in the inflammation in rats with IRI.     

Effects of tripterygium glycosides combined with dexamethasone on TLRs/NF-κB signaling pathway in EAE rats

AIM: To investigate the role of TLRs/NF-κB pathway in experimental allergic encephalomyelitis (EAE) rats treated with tripterygium glycosides (TG) + dexamethasone (DX). METHODS: Lewis rats were used in the study and divided into control group, EAE model group, therapy 1 group (EAE rats treated with DX) and therapy 2 group (EAE rats treated with DX+TG). The mean clinical score of the rats was determined. The expression of TLR4 and TLR9 at mRNA and protein levels was detected by the methods of real-time quantitative RT-PCR and immunohistochemistry. The protein level of NF-κB p65 was also measured. The levels of TNF-α, IL-1β and IL-6 were assayed by ELISA. RESULTS: The mean clinical scores at 5th, 16th and 20th day were lower in therapy 1 group and therapy 2 group than that in EAE model group. The mean clinical score in therapy 2 group was even lower than that in therapy 1 group. At the 16th day (the peaking period), the mRNA expression of TLR4 and TLR9 in therapy 1 group and therapy 2 group were obviously lower than that in EAE model group. The protein levels of TLR4, TLR9 and NF-κB p65 were also significantly lower in therapy 1 group and therapy 2 group than those in EAE model group at peak stage of EAE. The levels of TNF-α, IL-1β and IL-6 were lower in therapy1 group and therapy2 group than those in EAE model group. The significant differences of the mean clinical score, the mRNA expression of TLR4 and TLR9, the positive ratio of NF-κB p65 and the levels of TNF-α, IL-1β and IL-6 between therapy 1 group and therapy 2 group were found. The result of orthogonal factorial analysis of variance indicated that the difference of therapeutic effect between DX and DX+TG was significant (F=75.749, P<0.01). CONCLUSION: The TLRs/NF-κB pathway takes part in the pathological process of EAE. TG combined with DX alleviates the symptoms of EAE by suppressing inflammatory and immunological reactions of EAE.     

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.     

CB2 receptor agonist JWH133 exerts protective effects on rat model of paraquat-induced acute lung injury

AIM: To study the protective effects of cannabinoid CB2 receptor agonist JWH133 on rat acute lung injury induced by paraquat (PQ).METHODS: Male Sprague-Dawley rats (n=72) were randomly divided into 4 groups. PQ group: PQ was administered intraperitoneally at the dose of 20 mg/kg; Low-dose JWH133 pretreatment group (L-JWH133 group): JWH133 (5 mg/kg, ip) was administered 1 h before PQ exposure; high-dose JWH133 pretreatment group (H-JWH133 group): JWH133 (20 mg/kg, ip) was administered 1 h before PQ exposure; control group: 1 mL saline was administered intraperitoneally. Arterial blood, bronchoalveolar lavage fluid (BALF) and lung tissue samples were collected at 8 h, 1 d and 3 d after PQ exposure. PaO2 and the levels of TNF-α and IL-1β in BALF were measured via blood gas analyzer and ELISA, respectively. The pathological changes and lung injury scores were assessed at 3 d after PQ exposure. NF-κB and AP-1 protein levels were also determined by Western blotting.RESULTS: The decrease in PaO2, structural injury of the lung tissues, interstitial pulmonary edema, and the increase in IL-1β and TNF-α in BALF were observed in PQ-treated rats compared with control group. JWH133 pretreatment reduced the degree of lung tissue injury, decreased the levels of IL-1β and TNF-α in BALF and the NF-κB and AP-1 protein expression in the lung tissue compared with PQ group, especially in H-JWH133 group. CONCLUSION: CB2 receptor agonist JWH133 inhibits NF-κB and AP-1 protein expression in the lung tissues, and reduces the secretion of IL-1β and TNF-α in BALF after paraquat exposure, thus attenuating paraquat-induced acute lung injury.     

Effect of recombinant rat CC16 protein on LPS-induced expression of TNF-α, IL-6 and IL-8 in rat tracheal epithelial cells

AIM: To explore the effect of recombinamt rat CC16 protein (rCC16) on LPS-induced expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-8 in the rat tracheal epithelial (RTE) cells.METHODS: The RTE cells were incubated with rCC16 at concentrations of 0.5, 1.0 and 2.0 mg/L in serum-free media for 2 h prior to LPS (0.1 mg/L) treatment for further 24 h. The cells were harvested for assessing the mRNA levels of TNF-α, IL-6 and IL-8 by RT-qPCR. The cell culture supernatants were collected for analyzing the protein levels of TNF-α, IL-6 and IL-8 by ELISA. In addition, the nuclear translocation of nuclear factor-κB (NF-κB) p65 was tested by Western blot.RESULTS: rCC16 inhibited LPS-induced IL-6 and IL-8 expression at both mRNA and protein levels in the RTE cells in a concentration-dependent (0~2 mg/L) manner, as demonstrated by RT-qPCR and ELISA. However, no concentration-dependent manner between the dose of rCC16 and TNF-α expression was observed, and rCC16 inhibited LPS-induced TNF-α expression at lower concentration (0.5 mg/L). rCC16 concentration-dependently inhibited the effects of LPS on the level of nuclear translocation of NF-κB p65.CONCLUSION: rCC16 suppresses LPS-mediated TNF-α, IL-6 and IL-8 production through inactivation of NF-κB activity in RTE cells.[KEY WORDS] CC16 protein; Airway inflammation; LPS; Inflammatory mediators; Nuclear factor-κB     

Inhibitory effect of madecassoside on LPS-stimulated microglia

AIM: To observe the inhibitory effect of madecassoside on the LPS-stimulated microglia and to investigate its possible mechanism. METHODS: Microglia cells of neonatal Sprague-Dawley (SD) rats were cultured, isolated and purified. Microglia cells were activated with lipopolysaccharide (LPS). The inhibitory effect of madecassoside on microglia was measured by MTT assay. Tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β) were detected by ELISA. Cell cycle and apoptotic rate were evaluated by flow cytometry. The expression of TLR4 was detected by Western blotting. The expression of NF-κB was detected by RT-PCR. RESULTS: LPS induced the proliferation of microglia and release inflammatory cytokines significantly. Compared with LPS group, madecassoside inhibited the proliferation of microglia induced by LPS in a dose dependent manner. The IC₅₀ value of madecassoside was 10.97 nmol/L to microglia after incubation for 48 h. Madecassoside also decreased the levels of TNF-α and IL-6, increased the ratios of microglia at the G₂ phase and the apoptotic rate, decreased the expression of TLR4 and NF-κB significantly (P<0.05). CONCLUSION: Madecassoside has inhibitory effects on the proliferation of LPS-stimulated microglia, by which the mechanism may be related to inhibition of the expression of TLR4 and NF-κB, change of cell cycle distribution and induction of microglia apoptosis.     

Effects of NF-κB "decoy" oligodeoxynucleotides on TNF-α and IL-6 expression in LPS-induced mouse macrophages

AIM: To study the effect of NF-κB "decoy" oligodeoxynucleotides on TNF-α and IL-6 expression in LPS-induced mouse macrophages. METHODS: Mouse macrophage cell line J774.1 cells were cultured with LPS and liposome-mediated oligodeoxynucleotides, and the levels of TNF-α and IL-6 measured in the different culture supernatant by enzyme linked immunosorbent assay. RNA was extracted from macrophages, and the mRNA expression of TNF-α and IL-6 in macrophages was observed by RT-PCR. RESULTS: NF-κB "decoy" oligodeoxynucleotides decreased the expression of TNF-α and IL-6 in LPS-induced macrophages and inhibited generation of TNF-α and IL-6. The level of TNF-α and IL-6 did not change in control group. CONCLUSIONS: NF-κB "decoy" oligodeoxynucleotides inhibit the expression of TNF-α and IL-6 in LPS-induced macrophages, which is probably due to the specific inhibition of activated NF-κB binding sites .     

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.     

Changes of pro-inflammatory cytokines in serum and lung of rats with oleic acid-induced acute respiratory distress syndrome and the effect of anisodamine

AIM: To observe the changes of interleukin-6(IL-6), IL-8 and tumor necrosis factor-α(TNF-α) in serum and lung at different time, and the effects of anisodamine (654-2) treatment in rats with oleic acid-induced ARDS. METHODS: The ARDS model induced by intravenous injection of oleic acid in the rat was used and levels of IL-6, IL-8, TNF-α in serum and lung tissue supernatant were measured using enzyme linked immunosorbent assay (ELISA). RESULTS: Levels of serum and lung tissue IL-6, IL-8, TNF-α in oleic acid type ARDS 4 h group were increased significantly. These cytokines in oleic acid type ARDS 8 h group were lower than that of ARDS 4 h group, but serum IL-6, TNF-α and lung tissue IL-6 were still higher than that of control group . In oleic acid type ARDS 16 h group, serum IL-6, TNF-α were lower than that of the ARDS 8 h group and serum TNF-α and lung tissue IL-6 were higher than that of control group. After 654-2 treatment, the levels of serum and lung tissue IL-6, TNF-α were decreased significantly. CONCLUSION: IL-6, IL-8 and TNF- α might play important roles in the oleic acid-induced ARDS in the rat. 654-2 might alleviate ARDS by inhibiting excess production of IL-6 and TNF-α.     

Effect of GRK5 on activation of rat astrocytes

AIM: To study the effect of G-protein-coupled receptor kinase 5 (GRK5) on the activation of astrocytes in the brain cortex of newborn Wistar rats. METHODS: GRK5 gene was silenced in the model of rat brain cortex astrocytes in vitro for 24 h. N-acetylcysteine (NAC), which is a known inhibitor of NF-κB, was added into the culture medium according to gene silencing for 24 h. The expression levels of GFAP and caspase-3 were detected by the method of immunofluorescence, and the mRNA levels of NF-κB, TNF-α, IL-1β and iNOS were determined by real-time PCR. Moreover, the activity of SOD and concentrations of TNF-α and NO were measured. RESULTS: GRK5 gene silencing increased the expression of NF-κB at mRNA and protein levels obviously (P<0.01), and the mRNA levels of IL-1β and iNOS increased synchronously (P<0.01). Furthermore, caspase-3-positive cells in GRK5 siRNA group were increased compared with control siRNA group (P<0.01). Treatment with NAC obviously reduced the activity of NF-κB and weakened the effects induced by GRK5 siRNA (P<0.05). CONCLUSION: GRK5 siRNA increases NF-κB activity and induces the activation of astrocytes.     

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.     

Effects of Huaiyu decoctum on serum concentrations of TNF-α, IL-6 and IL-10 in rats after anorectal operation

ATM: To investigate the effects of Huaiyu decoctum on the serum concentrations of TNF-α, IL-6 and IL-10 in rats after anorectal operation. METHODS: Sprague-Dawley rats (n=40) were randomly divided into 4 groups:normal group, model group, low-dose Huaiyu decoctum group and high-dose Huaiyu decoctum group. The concentrations of TNF-α, IL-6 and IL-10 in the rat serum were measured by ELISA. The pathologic changes of the anorectal tissues were observed under microscope with HE staining. The protein expression of ICAM-1, VCAM-1 and NF-κB was determined by Western blotting. RESULTS: After Huaiyu decoctum administration, TNF-α and IL-6 concentrations in the serum were significantly decreased, and IL-10 concentration was increased as compared with model group. Moreover, Huaiyu decoctum markedly attenuated edema and hyperemia in the rats after anorectal operation. The protein expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and NF-κB in the anorectal tissues was obviously inhibited by Huaiyu decoctum treatment. CONCLUSION: Huaiyu decoctum improves the recovery of anorectal tissues after operation by decreasing the serum concentrations of TNF-α, IL-6 and IL-10, and reducing the protein expression of ICAM-1, VCAM-1 and NF-κB in the anorectal tissues.     

Toll-like receptor 3 signaling pathway plays an important role in cardiomyocyte apoptosis and inflammatory response in human viral myocarditis

AIM：To investigate the role of the signaling pathway mediated by Toll-like receptor 3 (TLR3) in cardiomyocyte apoptosis and inflammatory response in human viral myocarditis (VMC). METHODS：The expression of TLR3, TIR domain-containing adaptor inducing IFN-β(TRIF), NF-κB and casepase-3 in myocardial tissues was examined by the method of immunohistochemistry with SP staining, and the apoptosis of cardiomyocytes was detected by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL). The differences between VMC and control groups were analyzed. RESULTS： Compared with control group, the expression of TLR3, TRIF, NF-κB and casepase-3, and the apoptotic index in VMC group increased remarkably (P<0.05). The positive correlations between TLR3 and TRIF, between TLR3 and NF-κB, between TRIF and NF-κB, and between NF-κB and caspase-3 were observed. The change of the apoptotic index was in accordance with that of caspase-3. CONCLUSION：Inflammatory response and apoptosis mediated by TLR3 play an important role in the genesis and development of viral myocarditis．     

Inflammatory response in rat kidney with contrast-induced nephropathy

AIM：To observe the expression of tumor necrosis factor α (TNF-α) and nuclear factor κB (NF-κB) in the renal tissue of the rats with contrast-induced nephropathy (CIN). METHODS：Male Sprague-Dawley rats (n=96) were randomly divided into control group (n=48) and CIN group (n=48). The model rats in CIN group were intravenously injected with iodinated contrast media (76% compound diatrizoate injection,10 mL/kg), while the rats in control group were injected with the same volume of saline. Six rats in each group were sacrificed at 6 h, 12 h, 24 h, 48 h, 72 h, 5 d, 10 d and 15 d after intravenous injection, respectively, and the blood and kidney samples of the rats were obtained. The renal tubular injury was assessed by histological examination (HE staining). The expression of kidney injury molecule-1 (KIM-1), TNF-α and NF-κB at mRNA and protein levels in the renal tissues were semiquantitatively measured by the methods of RT-PCR and immunohistochemistry, respectively. The correlations between the expression of TNF-α, NF-κB and tubular injury score, KIM-1 expression in renal tissue of CIN group were analyzed. RESULTS：The levels of serum creatinine (SCr) and blood urea nitrogen (BUN) in control group were not changed between different time points (P>0.05). The levels of SCr and BUN in CIN group displayed significant increases at different time points (except 15 d) compared with control group (P<0.05). The renal tubular injury score in CIN group was significantly higher at all time points than that in control group (P<0.05). The expression of KIM-1, TNF-α and NF-κB at mRNA and protein levels up-regulated significantly at 6 h and the peaking of KIM-1 expression was at 24 h, while the peaking of TNF-α and NF-κB expression was at 48 h in CIN group. The expression of KIM-1,TNF-α and NF-κB was significantly increased in CIN group compared with control group except at 15 d (P<0.05). The expression of TNF-α and NF-κB at mRNA and protein levels showed close correlations with renal tubular injury score (r=0.843, 0.758, 0.743 and 0.707, P<0.05). The expression of TNF-α and NF-κB at mRNA and protein levels was also positively correlated with KIM-1 expression (r=0.863, 0.807, 0.839 and 0.855, P<0.05). CONCLUSION：The expression of TNF-α and NF-κB at mRNA and protein levels in the renal tissues of CIN group is up-regulated and is closely related with renal tubular injury, indicating that the inflammatory response is involved in the pathogenesis of CIN.     

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.     

Effect of NOD8 on production of nitric oxide,IL-1β and TNF-α in LPS-treated macrophages

AIM: To investigate the effect of NOD8 on lipopolysaccharide (LPS)-induced releases of nitric oxide (NO), tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) in RAW264.7 cells. METHODS: The plasmids of pEGFP-C2 and pEGFP-NOD8 were transfected into RAW264.7 cells respectively. The transfected and non-transfected cells were stimulated by LPS for 0, 6, 12 and 24 h. NO production was evaluated by Griess reagent assay, and the levels of IL-1β and TNF-α were measured by ELISA. The protein expression of NOD8 and the nuclear translocation of nuclear factor κB (NF-κB) p65 subunit were detected by Western blotting. The level of activated caspase-1 was determined by fluorimetric method. RESULTS: Compared with pEGFP-C2 group, the protein expression of NOD8 was significantly elevated in pEGFP-NOD8+LPS group. The releases of NO, IL-1β and TNF-α were obviously increased after RAW264.7 cells were treated with LPS for 6 h, 12 h and 24 h, and while the secretion of NO was significantly reduced in the cells transfected with pEGFP-NOD8 and induced by LPS for 12 h and 24 h, and the release of IL-1β was also significantly reduced at 6 h, 12 h and 24 h. However, no significant difference of TNF-α release was observed between pEGFP-C2+LPS group and pEGFP-NOD8+LPS group. The activation of caspase-1 in RAW264.7 cells stimulated with LPS for 6 h, 12 h and 24 h was markedly increased, and the expression of NF-κB p65 subunit in the cytoplasm was significantly decreased, indicating that p65 nuclear translocation was increased. In addition, the activation of caspase-1 and the nuclear translocation of p65 were significantly inhibited in pEGFP-NOD8+LPS group. CONCLUSION: NOD8 suppresses the releases of LPS-induced NO and IL-1β in RAW264.7 cells by inhibiting the activation of caspase-1 and NF-κB.     

Protective effects of taurine on LPS-induced myocardial damage in rats

AIM: To investigate the effects of taurine on lipopolysaccharide (LPS)-induced myocardial damage in rats. METHODS: Healthy male SD rats (n=30) were randomly divided into control group (CON), LPS model group (LPS) and taurine treatment group (TAU). The rats in CON group and LPS group were intravenously injected with normal saline, and the rats in TAU group were injected with taurine (100 mg/kg). After 2 h, the rats in LPS group and TAU group were intraperitoneally injected with LPS at 10 mg/kg, and the rats in CON group were injected with normal saline. Six hours after injection of LPS, the blood samples were collected for determination of superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) levels. The myocardial tissues were processed for histological examination and the analysis of Western blot. RESULTS: Compared with CON group, LPS significantly reduced SOD activity in the serum and heme oxygenase 1 (HO-1) protein expression in the myocardial tissues, increased the serum content of MDA and levels of TNF-α and IL-6. LPS also significantly elevated the levels of TNF-α and IL-6, and up-regulated the cyclooxygenase-2 (COX-2) expression and phosphorylation of nuclear factor kappa B (NF-κB) in the myocardial tissues. Taurine pretreatment significantly elevated SOD activity and HO-1 protein expression level, decreased the levels of COX-2, TNF-α, IL-6 and phosphorylated NF-κB. Histological observation showed that taurine reduced inflammatory response in the myocardial tissue. CONCLUSION: Taurine attenuates LPS-induced myocardial damage in rats. The beneficial effects of taurine may be associated with its reduction of p-NF-κB/COX-2 signaling by activation of HO-1/CO.