Pathogenic role leukotriene B4 in lung injury induced by lung-protective mechanical ventilation in rabbits / 南方医科大学学报

OBJECTIVE@#To elucidate the pathogenic role of leukotriene B4 (LTB4) in pulmonary hyper-permeability and inflammation induced by lung-protective mechanical ventilation (LPMV) in rabbits.@*METHODS@#Thirty-two healthy Japanese white rabbits were randomized into 4 groups for treatment with vehicle or bestatin (a leukotriene A4 hydrolase inhibitor that inhibits LTB4 production) administered intragastrically at the daily dose of 8 mg/kg for 5 days, followed by sham operation (group S and group BS, respectively, in which the rabbits were anesthetized only) or LPMV (group PM and group BPM, respectively, in which the rabbits received ventilation with 50% oxygen at a tidal volume of 8 mL/kg for 5 h). The concentrations of LTB4 and cyclic adenosine monophosphate (cAMP) in the lung tissues were analyzed by ELISA. cAMP content, protein kinase A (PKA) protein expression and the Rap1-GTP protein to total Rap1 protein ratio were determined to assess the activities of cAMP/PKA and Rap1 signaling pathways. The lung injury was evaluated by assessing lung permeability index, lung wet/dry weight ratio, polymorphonuclear leukocyte (PMN) count in bronchoalveolar lavage fluid (BALF), pulmonary myeloperoxidase (MPO) activity and lung histological scores.@*RESULTS@#None of the examined parameters differed significantly between group S and group BS. All the parameters with the exception of lung histological score increased significantly in group PM and group BPM as compared to those in group S (@*CONCLUSIONS@#LPMV can induce LTB4 overproduction to down-regulate cAMP/PKA and Rap1 signaling pathways in the lungs of rabbits, which results in lung hyper-permeability and inflammation. Bestatin can inhibit LTB4 production in the lungs to protect against LPMV-induced lung hyper-permeability and inflammation.

Root canal contamination or exposure to lipopolysaccharide differentially modulate prostaglandin E 2 and leukotriene B 4 signaling in apical periodontitis

Abstract Purpose To evaluate the kinetics of apical periodontitis development in vivo , induced either by contamination of the root canals by microorganisms from the oral cavity or by inoculation of bacterial lipopolysaccharide (LPS) and the regulation of major enzymes and receptors involved in the arachidonic acid metabolism. Methodology Apical periodontitis was induced in C57BL6 mice (n=96), by root canal exposure to oral cavity (n=48 teeth) or inoculation of LPS (10 µL of a suspension of 0.1 µg/µL) from E. coli into the root canals (n= 48 teeth). Healthy teeth were used as control (n=48 teeth). After 7, 14, 21 and 28 days the animals were euthanized and tissues removed for histopathological and qRT-PCR analyses. Histological analysis data were analyzed using two-way ANOVA followed by Sidak's test, and qRT-PCR data using two-way ANOVA followed by Tukey's test (α=0.05). Results Contamination by microorganisms led to the development of apical periodontitis, characterized by the recruitment of inflammatory cells and bone tissue resorption, whereas inoculation of LPS induced inflammatory cells recruitment without bone resorption. Both stimuli induced mRNA expression for cyclooxygenase-2 and 5-lipoxygenase enzymes. Expression of prostaglandin E 2 and leukotriene B 4 cell surface receptors were more stimulated by LPS. Regarding nuclear peroxisome proliferator-activated receptors (PPAR), oral contamination induced the synthesis of mRNA for PPARδ, differently from inoculation of LPS, that induced PPARα and PPARγ expression. Conclusions Contamination of the root canals by microorganisms from oral cavity induced the development of apical periodontitis differently than by inoculation with LPS, characterized by less bone loss than the first model. Regardless of the model used, it was found a local increase in the synthesis of mRNA for the enzymes 5-lipoxygenase and cyclooxygenase-2 of the arachidonic acid metabolism, as well as in the surface and nuclear receptors for the lipid mediators prostaglandin E2 and leukotriene B4.

Leukotriene B4 in equine asthma syndrome: what do we know so far? / Leucotrieno B4 na síndrome asmática equina: o que sabemos até o momento?

The term "equine asthma syndrome" (EAS) was recently proposed due to the resemblance of the equine disease to human asthma. Leukotrienes cause constriction of the bronchi, especially in the lower airways and increase mucus secretion in the respiratory system. Leukotriene B4 (LTB4) has been discovered as a strong chemotactic factor, which plays a role in neutrophil migration. The immunologic background of EAS remains not fully elucidated despite many studies on the pathogenesis. This study aimed to evaluate the LTB4 concentration in the bronchoalveolar lavage fluid (BALF) of horses with and without pulmonary inflammatory disease. Thirty-five mixed breed horses were studied and LTB4 was determined by using specific ELISA Kit. The horses were grouped by 2 different criteria for statistical analysis of data: 1) according to the values for BALF citology and 2) according to the detection of LTB4 in BALF. There was significant difference of effect of age on the LTB4 detection in equine BALF. Younger animals were the majority where it was possible to detect LTB4 values in LBA. In conclusion, there was an effect of age on the detection of LTB4 in equine BALF, where LTB4 levels were more easily detected in younger animals than older animals and the results of this study raise the possibility of considering future studies with the objective of establishing the real role and the best moment to detect LTB4 in BALF of the equine asthma syndrome.(AU)

Recentemente, o termo "síndrome da asma equina" (SAE) foi proposto devido à semelhança da doença equina à asma humana. Os leucotrienos causam constrição dos brônquios, especialmente nas vias aéreas posteriores e aumentam a secreção de muco no sistema respiratório. O leucotrieno B4 (LTB4) foi descoberto como um forte fator quimiotático, que desempenha um papel na migração de neutrófilos. O fundo imunológico do SAE permanece não completamente elucidado apesar de muitos estudos sobre a patogênese. Este estudo teve como objetivo avaliar a concentração de LTB4 no lavado broncoalveolar (LBA) de equinos com e sem doença inflamatória pulmonar. Trinta e cinco cavalos de raças mistas foram estudados e o LTB4 foi determinado usando o kit ELISA específico. Os animais foram agrupados por dois critérios diferentes para análise estatística dos dados: 1) de acordo com os valores para citologia do LBA e 2) de acordo com a detecção do LTB4 no LBA. Houve diferença significativa do efeito da idade na detecção do LTB4 no LBA equino. Os animais mais jovens foram a maioria onde foi possível detectar os valores de LTB4 no LBA. Em conclusão, houve um efeito da idade na detecção de LTB4 em LBA equino, onde os níveis de LTB4 foram mais facilmente detectados em animais jovens do que em animais mais velhos e foi possível detectar a concentração de LTB4 no LBA equino e os resultados deste estudo levantam a possibilidade de considerar futuros estudos com o objetivo de estabelecer o real papel e o melhor momento para detectar LTB4 no LBA da síndrome asmática equina.(AU)

Diverse characters of Brennan’s paw incision model regarding certain parameters in the rat / 대한통증학회지

BACKGROUND: Brennan’s rodent paw incision model has been extensively used for understanding mechanisms underlying postoperative pain in humans. However, alterations of physiological parameters like blood pressure and heart rate, or even feeding and drinking patterns after the incision have not been documented as yet. Moreover, though eicosanoids like prostaglandins and leukotrienes contribute to inflammation, tissue levels of these inflammatory mediators have never been studied. This work further investigates the antinociceptive effect of protein C after intra-wound administration. METHODS: Separate groups of Sprague–Dawley rats were used for quantitation of cyclooxygenase (COX) activity and leukotriene B4 level by enzyme-linked immunosorbent assay, as well as estimation of cardiovascular parameters and feeding and drinking behavior after paw incision. In the next part, rats were subjected to incision and 10 μg of protein C was locally administered by a micropipette. Both evoked and non-evoked pain parameters were then estimated. RESULTS: COX, particularly COX-2 activity and leukotriene B4 levels increased after incision. Hemodynamic parameters were normal. Feeding and drinking were affected on days 1 and 3, and on day 1, respectively. Protein C attenuated non-evoked pain behavior alone up to day 2. CONCLUSIONS: Based upon current observations, Brennan’s rodent paw incision model appears to exhibit a prolonged period of nociception similar to that after surgery, with minimal interference of physiological parameters. Protein C, which is likely converted to activated protein C in the wound, attenuated the guarding score, which probably represents pain at rest after surgery in humans.

Inhibitory effect of the aqueous extract of a tetraploid ‘etteum’ variety in Platycodon grandiflorum on degranulation and inflammatory mediator release in RBL-2H3 cells / 한국영양학회지

PURPOSE: Platycodon grandiflorum (a domestic diploid variety, DV-PG) has been used as a food and component of various traditional oriental medicines. Although DV-PG is known to have an anti-allergic effect, little is known about the beneficial health effects of the tetraploid ‘Etteum’ variety in the Platycodon grandiflorum (TV-PG), which is a recently developed variety. In this study, we investigated the effect of TV-PG on the rat basophilic leukemia mast cell (RBL-2H3)-mediated allergic response. METHODS: To examine the effects of TV-PG on the allergic response, RBL-2H3 cells were sensitized with dinitropheny (DNP)-immunoglobin E, treated with various concentrations of TV-PG, and challenged with DNP-human serum albumin. We estimated cell granulation by measuring the release of β-hexosaminidase and production of inflammatory mediators by ELISA. RESULTS: TV-PG had no effect on the proliferation or cytotoxicity of RBL-2H3 cells within the concentration range of 0 to 200 µg/mL. TV-PG inhibited degranulation of RBL-2H3 cells by antigen stimulation in a dose-dependent manner. TV-PG also suppressed the production of inflammatory cytokines and mediators such as interleukin-4, tumor necrosis factor-α, prostagladin E2, and leukotriene B4 in RBL-2H3 cells by antigen stimulation. CONCLUSION: These results indicate that TV-PG exhibits anti-allergic activity via inhibition of degranulation as well as suppression of inflammatory mediators and cytokine release. These findings suggest that TV-PG may have potential as a preventive and therapeutic agent for the treatment of various allergic diseases.

Avaliação do efeito do antagonismo do receptor de leucotrienos na modulação da periodontite experimental em ratos / Cysteinyl leukotriene receptor antagonism modulates experimental periodontitis in rats

Na doença periodontal, quando ativada a resposta imunoinflamatória do hospedeiro, os leucotrienos (LTs) participam do processo de lesão tecidual pela quimiotaxia de leucócitos e ativação osteoclástica. O uso de antagonista do receptor de LTs está relacionado com a expressão de moléculas pró-inflamatórias e osteoclastogênese. No entanto, suas implicações na progressão da DP ainda não foram estudadas. Sendo assim, o trabalho teve como objetivo avaliar o efeito de antagonista do receptor de LTs (Montelucaste - MT) na modulação da periodontite experimental induzida pelo método da ligadura em ratos. Ratos Wistar machos (6-8 semanas, 200-250 gramas) foram divididos (12 animais/ grupo) nos seguintes grupos experimentais: Sham - sem ligadura/ sem tratamento (carboximetilcelulose - CMC 0,5%, via gavagem); Periodontite - com ligadura/ sem tratamento; MT 10 - com ligadura/ com tratamento (Montelucaste 10 mg/kg/dia, via gavagem); MT 30 - com ligadura/ com tratamento (Montelucaste 30 mg/kg/dia, via gavagem). Após período experimental (7, 14 e 21 dias) os animais foram submetidos à eutanásia e as hemimandíbulas retiradas para realização da análise de perda óssea alveolar (POA) macroscópica, análise histológica (H&E - histopatológico; picrosirius - colágeno), ELISA (LTB4), atividade de mieloperoxidase (MPO), avaliação de marcadores do estresse oxidativo (glutationa, expressão de proteínas carboniladas e proteínas modificadas por 4HNE) e expressão gênica de receptor do ativador de fator nuclear kappa B (RANK), ligante de RANK (RANKL), osteoprotegerina (OPG), fator de transcrição relacionado ao runt 2 (RUNX2), Colágeno tipo I, receptor de LT 1 (BLT1), receptor 1 de cisteinil-leucotrieno (CisLTR1), LTA4 hidrolase (LTA4H) e LTC4 sintase (LTC4S) (ANOVA, pós teste Sidak, p<0,05). O grupo Periodontite apresentou maior POA em comparação ao grupo Sham nos três períodos experimentais avaliados (p<0,05). MT passou a ser efetivo na redução da POA a partir do 14º dia (p<0,05). Ao analisar a degradação de colágeno, no 21º dia os grupos Periodontite e MT apresentaram maior perda em comparação ao grupo Sham (p<0,05). Não foram encontradas diferenças estatísticas quanto à expressão de LTB4 pelo teste ELISA (p>0,05), bem como na avaliação de marcadores de estresse oxidativo, independente do teste realizado (p>0,05). Em relação à MPO, o grupo Periodontite apresentou valores estatisticamente maiores em comparação ao grupo Sham nos três períodos experimentais (p<0,05). Nos períodos de 7 e 14 dias (30 mg/kg) o grupo MT promoveu diminuição da infiltração granulocítica em comparação ao grupo Periodontite (p<0,05), sem diferença em relação ao grupo Sham (p>0,05). Observou-se que a expressão de colágeno tipo 1 não apresentou diferença significante entre os grupos (p>0,05), e que o grupo MT 30 apresentou maior expressão de RUNX2 em comparação aos grupos Sham e Periodontite (p<0,05). No grupo MT 30 houve uma redução significante da expressão de LTA4H, BLT1 e LTC4S (p<0,05). A expressão de CysLTR1 não diferiu entre os grupos (p>0,05). Conclui-se que o uso de antagonista de receptor de LTs foi efetivo na redução do infiltrado granulocítico e da POA, com aumento de RUNX2.

Tryptophan Negatively Regulates IgE-mediated Mast Cell Activation / 체질인류학회지

Mast cells are major immune cells in allergy to secrete allergic mediators by a degranulation process and make and secrete inflammatory lipids and cytokines in response to antigen stimulation. An amino acid tryptophan regulates immune functions. Tryptophan ameliorates inflammatory colitis in which mast cells are engaged. However, its effects on mast cells remain to be solved. We investigated the effect of tryptophan on IgE-mediated allergic responses in the mast cells and mice. IgE-mediated passive cutaneous anaphylaxis (PCA) in mice were examined. Also IgE-mediated mast cell activation responses such as degranulation of stored granules and secretion of inflammatory lipid LTB₄ and cytokines (TNF-α and IL-4) were measured. Intraperitoneal administration of tryptophan suppressed PCA in mice. Also, in the cellular level tryptophan inhibited IgE-mediated mast cell activation such as IgE-mediated degranulation and the production of LTB₄. Also, it inhibited production of inflammatory cytokines TNF-α and IL-4. In summary, tryptophan suppressed IgE-mediated allergic activation in vivo and in vitro. Tryptophan supplementation is beneficial for IgE-mediated allergy.

Gastroprotective Effects of PMK-S005 against Ethanol-Induced Acute Gastric Damage in Rats

BACKGROUND/AIMS: This study aimed to examine the gastroprotective effects of PMK-S005, which is a synthetic S-allyl-L-cysteine (SAC; a sulfur-containing amino acid), against acute ethanol-induced gastric damage in rats. METHODS: Sprague-Dawley rats were divided into six groups, including a nonethanol group, groups treated with absolute ethanol 1 hour after pretreatment with various doses of PMK-S005 (1, 5, and 10 mg/kg) or rebamipide (50 mg/kg), and an absolute ethanol-only group. Ethanol-induced gross ulcer and mucus levels were measured. Myeloperoxidase, tumor necrosis factor α, interleukin 1β, PGE2, LTB4, cPLA2, COX-1, and COX-2 levels were estimated by enzyme-linked immunosorbent assay or Western blot analysis. Furthermore, the protein expression levels of antioxidant enzymes, including heme oxygenase-1 (HO-1), NAD(P)H:quinine oxidoreductase 1 (NQO-1), GCLC, and GCLM, were assessed. RESULTS: PMK-S005 significantly attenuated the ethanol-induced gastric damage; it reduced mucosal inflammatory cytokine production and increased mucus levels. The expression levels of cPLA2, COX-1, and COX-2 were decreased by PMK-S005. PMK-S005 did not affect PGE2 synthesis, but LTB4 production was significantly suppressed. In addition, long-term administration of PMK-S005 significantly increased the expression of HO-1, NQO-1, GCLC, and GCLM. CONCLUSIONS: These results strongly suggest that PMK-S005 prevents gastric mucosal damage and that these gastroprotective activities are due to anti-inflammatory effects and enhancement of the gastric defense system, including antioxidant enzymes.

A rare case of Sjogren-Larsson syndrome with recurrent pneumonia and asthma / 소아과

Sjogren-Larsson syndrome (SLS) is a rare autosomal recessive neurocutaneous disorder with worldwide incidence of 0.4 per 100,000 people. It is characterized by the triad of congenital ichthyosis, spastic diplegia or quadriplegia, and mental retardation. Herein we report a 2-year-old male child with SLS, asthma, and recurrent pneumonia. SLS was confirmed by a molecular genetics study that revealed a deletion mutation in the ALDH3A2 gene. An ALDH3A2 gene mutation results in dysfunction of the microsomal enzyme fatty aldehyde dehydrogenase and impaired metabolism and accumulation of leukotriene B4, which is a key molecule and a pro-inflammatory mediator in developing allergic diseases, especially asthma. An increased level of leukotriene B4 has been reported in SLS patients. As far as we are aware, this is the first report of SLS associated with asthma and recurrent pneumonia. In conclusion, pediatricians should be aware of and evaluate patients with SLS for possible associated asthma and allergic disorders.

Effects of docosahexaenoic acid on inflammation-associated cytokines in blood and pulmonary tissue of rats with severe scald injury / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the effects of docosahexaenoic acid (DHA) on the expressions of TNF-α, IL-6, and leukotriene B4 (LTB4) in serum and expression of NF-κB in pulmonary tissue of rats with severe scald injury.</p><p><b>METHODS</b>One hundred and sixty SD rats were divided into sham injury (A), sham injury+DHA (B), scald (C), and scald+DHA (D) groups according to the random number table, with 40 rats in each group. Rats in groups A and B were sham injured, while rats in groups C and D were inflicted with 30% TBSA full-thickness scald on the back. Rats in groups B and D were injected with 0.5 mg/mL DHA solution with the dosage of 1 mL/kg via tail vein 5 minutes post injury, while rats in groups A and C with normal saline solution 1 mL/kg. At post injury hour (PIH) 3, 6, 12, 24, and 48, pulmonary tissue and abdominal aorta blood were collected from 8 rats in each group. The serum levels of TNF-α, IL-6, and LTB4 were determined with ELISA, and the protein expression of NF-κB p65 in pulmonary tissue was determined with Western blotting. Data were processed with analysis of variance of factorial design and LSD-t test.</p><p><b>RESULTS</b>(1) The serum levels of TNF-α and IL-6 of rats in group A were similar to those of group B at each time point (with tTNF-α values from 0.223 to 0.947, tIL-6 values from 0.767 to 2.084, P values above 0.05). Compared with those of group A, the serum levels of TNF-α and IL-6 of rats in groups C and D were significantly higher at each time point (with tTNF-α values from 11.800 to 40.357, tIL-6 values from 10.334 to 39.321, P values below 0.01). The serum levels of TNF-α and IL-6 of rats in group D were significantly lower than those of group C at each time point (with tTNF-α values from -17.643 to -8.331, tIL-6 values from -21.596 to -6.332, P values below 0.01). The serum levels of TNF-α and IL-6 in groups C and D both showed a trend of increase earlier and decrease later, and they peaked at PIH 12, respectively (360.4 ± 13.2), (306.8 ± 7.2) pg/mL and (265.4 ± 12.3), (230.5 ± 2.2) pg/mL. (2) The serum level of LTB4 in group A was similar to that of group B at each time point (with t values from 0.787 to 1.096, P values above 0.05). The serum level of LTB4 was significantly higher in groups C and D than in group A at each time point (with t values from 7.501 to 38.962, P values below 0.01). The serum level of LTB4 in group D was obviously lower than that of group C at each time point (with t values from -19.244 to -2.532, P values below 0.01). The serum level of LTB4 in groups C and D both showed a trend of increase earlier and decrease later, and it peaked at PIH 12, (4.59 ± 0.29) and (2.85 ± 0.32) ng/mL respectively. (3) The protein expression of NF-κB p65 in pulmonary tissue in group A was similar to that of group B at each time point (with t values from 0.847 to 1.256, P values above 0.05). The protein expression of NF-κB p65 was significantly higher in groups C and D than in group A at each time point (with t values from 15.167 to 98.074, P values below 0.01). The protein expression of NF-κB p65 in group D was obviously lower than that of group C at each time point (with t values from -37.190 to -14.415, P values below 0.01). The protein expression of NF-κB p65 in groups C and D both showed a trend of increase earlier and decrease later, and it peaked at PIH 12, respectively 4.46 ± 0.12 and 2.94 ± 0.21.</p><p><b>CONCLUSIONS</b>Parenteral supply of DHA to rats with severe scald injury can reduce the levels of TNF-α, IL-6, and LTB4 in serum and decrease the expression of NF-κB in pulmonary tissue, thus alleviating the inflammation response.</p>

Clinical efficacy of montelukast for the treatment of bronchiolitis in infants / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To observe the effect of montelukast treatment on levels of serum leukotriene B4 and urinary leukotriene E4 in infants with bronchiolitis.</p><p><b>METHODS</b>Seventy-five children who were diagnosed with bronchiolitis between June 2014 and December 2014 were randomly assigned into two groups, one with thirty-eight cases as the montelukast treatment group and another thirty-seven cases as the control group. All of the children were given routine medical treatment. The children in the montelukast treatment group were additionally given montelukast daily (4 mg once a day, for 7 days). The serum leukotriene B4 and urinary leukotriene E4 levels were measured using ELISA before and after treatment. The relationship between serum leukotriene B4 and urinary leukotriene E4 levels was analyzed by Peason correlation analysis.</p><p><b>RESULTS</b>After 7 days of treatment, the serum leukotriene B4 and urinary leukotriene E4 levels in the montelukast treatment and control groups were significantly reduced compared with before treatment (P<0.05). The montelukast treatment group showed significantly lower serum leukotriene B4 and urinary leukotriene E4 levels than the control group (P<0.05). The remission time of cough, wheezing and lung wheezes and the length of hospital stay in the montelukast treatment group were significantly shortened compared with the control group (P<0.05). There was a positive correlation between serum leukotriene B4 and urinary leukotriene E4 levels (r=0.723, P<0.05).</p><p><b>CONCLUSIONS</b>Montelukast has a reliable clinical curative efficacy for bronchiolitis in infants, possibly by decreasing serum leukotriene D4 and urinary leukotriene E4 levels.</p>

The antalgic and antiphiogistic function and mechanism of RGDT plaster / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the antalgic and antiphlogistic functions and mechanism of ronggudingtong (RGDT) plaster (traditional Chinese medicine).</p><p><b>METHODS</b>The painful models were established with hot plate test or acetic acid writhing and the inflammatory models were established with daubing dimethylbenzene on auricle or injecting formaldehyde in toe or synovial envelope to study the antalgic and antiphlogistic functions of RGDT Plaster. The total protein and leukotriene B4(LTB4) in inflammatory exudate were detected to investigate the antalgic and antiphlogistic mechanism of RGDT plaster. The mice were randomly divided into different groups (n = 11), on the basis of drug using, the indexes of pain threshold, swelling degree were observed. Sixty-six mice were used to establish gasbag synovitis model and randomly divided into normal control group,model control group, positive control group (Voltaren gel 0.8 mg/d)and low/medium/high dosage RGDT plaster treating groups(30 mg/d, 60 mg/d, 120 mg/d).</p><p><b>RESULTS</b>30 mg/d, 60 mg/d,120 mg/d RGDT plaster could upgrade the pain thresholds, remit auricular and foot swelling (P < 0.05, P < 0.01), and degrade total protein and LTB4 in inflammatory exudates (P < 0.05, P < 0.01).</p><p><b>CONCLUSION</b>RGDT plaster has some antalgic and antiphlogistic functions, and one of the mechanisms is depressing synthesis of LTB4.</p>

MyD88-BLT2-dependent cascade contributes to LPS-induced interleukin-6 production in mouse macrophage

Endotoxic responses to bacterial lipopolysaccharide (LPS) are triggered by Toll-like receptor 4 (TLR4) and involve the production of inflammatory mediators, including interleukin-6 (IL-6), by macrophages. The detailed mechanism of IL-6 production by macrophages in response to LPS has remained unclear, however. We now show that LPS induces IL-6 synthesis in mouse peritoneal macrophages via the leukotriene B4 receptor BLT2. Our results suggest that TLR4-MyD88 signaling functions upstream of BLT2 and that the generation of reactive oxygen species (ROS) by NADPH oxidase 1 (Nox1) and consequent activation of the transcription factor nuclear factor (NF)-kappaB function downstream of BLT2 in this response. These results suggest that a TLR4-MyD88-BLT2-Nox1-ROS-NF-kappaB pathway contributes to the synthesis of IL-6 in LPS-stimulated mouse macrophages.

Effects of natural eggshell membrane (NEM) on monosodium iodoacetate-induced arthritis in rats / 한국영양학회지

PURPOSE: The aim of this study is to investigate anti-arthritis activity using natural eggshell membrane (NEM). METHODS: NEM was administered at 52 mg/kg, 200 mg/kg, and 400 mg/kg to SD-Rat, where arthritis was induced by monosodium iodoacetate (MIA) at 3 mg. NO production in serum was measured using Griess reagent. Cytokines including IL-1beta, and IL-6 were measured by Luminex and PGE2, MMP-2, MMP-9, TIMP-1, LTB4, and hs-CRP were measured by ELISA. The cartilage of patella volume was examined and 3-D high-resolution reconstructions of the cartilage of patella were obtained using a Micro-CT system. RESULTS: Production of NO, IL-1beta, IL-6, PGE2, MMP-2, MMP-9, TIMP-1, LTB4, and hs-CRP in serum was decreased, respectively, in comparison with control. The cartilage of patella volume increased significantly. In addition, the NEM group showed a decrease in the cartilage of patella, synovial membrane, and transformation of fibrous tissue. CONCLUSION: The results for NEM showed significant anti-arthritis activity. These results may be developed as a raw material for new health food to ease the symptoms mentioned above.

Increased inflammatory mediator in exhaled breath condensate from asthmatic children

PURPOSE: There has recently been increasing interest in the use of exhaled breath condensate (EBC) as a simple noninvasive means for understanding the physiology of asthma. The aim of this study was to evaluate the levels of leukotriene B4 (LTB4) and eosinophil cationic protein (ECP) in the EBC of asthmatic children. METHODS: We measured LTB4 and ECP levels in EBC from children aged 6-14 years, including healthy children (n=25) and asthmatic children (n=25). We also measured serum LTB4 and serum ECP. Pulmonary function tests and methacholine challenge tests were performed on all subjects. RESULTS: Exhaled LTB4 levels were increased significantly in patients with asthma compared to normal subjects (7.1+/-3.7 pg/mL vs. 2.2+/-1.7 pg/mL, P<0.05). Serum LTB4 levels were not significantly different in patients with asthma compared to normal subjects (674.7+/-484.1 pg/mL vs. 487.1+/-272.0 pg/mL, P=0.156,) and no significant correlations were found between exhaled and serum LTB4 concentrations in children with asthma (r=0.052, P=0.758). Exhaled ECP levels were not significantly different in patients with asthma compared to normal subjects (P=0.419). Serum ECP levels were significantly increased in patients with asthma compared to normal subjects (44.37+/-32.14 microg/L vs. 16.40+/-13.23 microg/L, P=0.001). CONCLUSION: We found significantly elevated LTB4 levels in the EBC of asthmatic children. Our results suggest that EBC may be one of the supportive tools to measure airway inflammation in children with asthma.

The Protective Effect of Eupatilin against Hydrogen Peroxide-Induced Injury Involving 5-Lipoxygenase in Feline Esophageal Epithelial Cells

In this study, we focused to identify whether eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone), an extract from Artemisia argyi folium, prevents H2O2-induced injury of cultured feline esophageal epithelial cells. Cell viability was measured by the conventional MTT reduction assay. Western blot analysis was performed to investigate the expression of 5-lipoxygenase by H2O2 treatment in the absence and presence of inhibitors. When cells were exposed to 600 microM H2O2 for 24 hours, cell viability was decreased to 40%. However, when cells were pretreated with 25~150 microM eupatilin for 12 hours, viability was significantly restored in a concentration-dependent manner. H2O2-treated cells were shown to express 5-lipoxygenase, whereas the cells pretreated with eupatilin exhibited reduction in the expression of 5-lipoxygenase. The H2O2-induced increase of 5-lipoxygenase expression was prevented by SB202190, SP600125, or NAC. We further demonstrated that the level of leukotriene B4 (LTB4) was also reduced by eupatilin, SB202190, SP600125, NAC, or nordihydroguaiaretic acid (a lipoxygenase inhibitor) pretreatment. H2O2 induced the activation of p38MAPK and JNK, this activation was inhibited by eupatilin. These results indicate that eupatilin may reduce H2O2-induced cytotoxicity, and 5-lipoxygenase expression and LTB4 production by controlling the p38 MAPK and JNK signaling pathways through antioxidative action in feline esophageal epithelial cells.

Expression of extracellular matrix metalloproteinase inducer in the unstable plaque of patients with acute coronary syndrome / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) in the unstable plaque of patients with acute coronary syndrome (ACS), and the impact of leukotriene B4 (LTB4) on the EMMPRIN expression in macrophages.</p><p><b>METHODS</b>The EMMPRIN expression was detected by immunohistochemistry in 11 unstable plaques from patients with ACS. Protein expression of EMMPRIN was evaluated by Western blot on macrophages differentiated from THP-1 which were stimulated with LTB4 in the absence or presence of LTB4 antagonist U75302. There are 8 study groups: 1-THP-1, 2-8-the macrophages derived from THP-1, 2-6-macrophages were stimulated by LTB4 (0, 10(-10), 10(-9), 10(-8) and 10(-7) mol/L) for 24 h, 7-8-the macrophages were pretreated by 10(-6) mol/L or 10(-7) mol/L U75302 2 h before the LTB4 (10(-7) mol/L) stimulation.</p><p><b>RESULTS</b>Abundant EMMPRIN expression was detected in macrophages and smooth muscle cells of unstable plaques from ACS patients. As to the THP-1 derived macrophages, EMMPRIN expression was significantly upregulated in a concentration-dependent manner in LTB4 stimulated groups, which was significantly higher in group 3-6 than in the THP-1 group (group 1) and macrophages group (group 2) (all P < 0.05) and pretreatment with U75302 significantly reduced the LTB4 induced upregulation of EMMPRIN in a dose-dependent manner (P < 0.05).</p><p><b>CONCLUSION</b>EMMPRIN expression is enhanced in macrophages and smooth muscle cells on unstable coronary artery plaques from ACS patients. LTB4 could stimulate EMMPRIN expression on THP-1 derived macrophages suggesting that LTB4 and EMMPRIN might be both involved in the formation and progression of unstable plaques, future studies are warranted to explore if LTB4 and EMMPRIN antagonists are effective or not for treating patients with ACS.</p>

5-(4-Hydroxy-2,3,5-trimethylbenzylidene) thiazolidine-2,4-dione attenuates atherosclerosis possibly by reducing monocyte recruitment to the lesion

A variety of benzylidenethiazole analogs have been demonstrated to inhibit 5-lipoxygenase (5-LOX). Here we report the anti-atherogenic potential of 5-(4-hydroxy-2,3,5-trimethylbenzylidene) thiazolidin-2,4-dione (HMB-TZD), a benzylidenethiazole analog, and its potential mechanism of action in LDL receptor-deficient (Ldlr-/-) mice. HMB-TZD Treatment reduced leukotriene B4 (LTB4) production significantly in RAW264.7 macrophages and SVEC4-10 endothelial cells. Macrophages or endothelial cells pre-incubated with HMB-TZD for 2 h and then stimulated with lipopolysaccharide or tumor necrosis factor-alpha (TNF-alpha) displayed reduced cytokine production. Also, HMB-TZD reduced cell migration and adhesion in accordance with decreased proinflammatory molecule production in vitro and ex vivo. HMB-TZD treatment of 8-week-old male Ldlr-/- mice resulted in significantly reduced atherosclerotic lesions without a change to plasma lipid profiles. Moreover, aortic expression of pro-atherogenic molecules involved in the recruitment of monocytes to the aortic wall, including TNF-alpha , MCP-1, and VCAM-1, was downregulated. HMB-TZD also reduced macrophage infiltration into atherosclerotic lesions. In conclusion, HMB-TZD ameliorates atherosclerotic lesion formation possibly by reducing the expression of proinflammatory molecules and monocyte/macrophage recruitment to the lesion. These results suggest that HMB-TZD, and benzylidenethiazole analogs in general, may have therapeutic potential as treatments for atherosclerosis.

Chemopreventive effect of boswellic acid and curcumin on 7,12-dimethyl benzanthracene-induced hamster cheek pouch carcinogenesis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the chemopreventive effects of boswellic acid and curcumin on 7,12-dimethyl benzanthracene(DMBA)-induced oral carcinogenesis in the hamster cheek pouch model.</p><p><b>METHODS</b>Male Syrian golden hamsters (6 - 8 weeks old, 80 - 130 g in weight) were randomly divided into seven groups, with group A serving as the untreated negative control. The left cheek pouch of the remaining hamsters was topically treated with 0.5% DMBA in mineral oil three times a week for 6 weeks. They were then randomized to six groups with group B serving as a positive control and receiving no further treatment. Groups C-G were treated topically with 5, 10 mg/L boswellic acid, 5, 10 µmol/L curcumin, or the combination of 5 mg/L boswellic acid and 5 µmol/L curcumin three times per week for 18 weeks. The animals were injected with bromodeoxyuridine intraperitoneally at 50 mg/kg 2 h prior to killing. At the 25 th week all the hamsters were sacrificed and cheek pouch tissue was harvested. One half of the tissue was snap frozen in liquid nitrogen for analysis of arachidonic acid metabolites, and the other half was fixed in 10% phosphate-buffered saline(PBS)-buffered formalin for histopathological examination.</p><p><b>RESULTS</b>Six-weeks of DMBA followed by 18-weeks of topical application of boswellic acid and curcumin, both boswellic acid (5, 10 mg/L) and curcumin (5, 10 µmol/L) significantly inhibited the incidence from 93.8% to 73.9% (P > 0.05), numbers from 2.19 ± 0.98 to 1.13 ± 0.81 (P < 0.01) and size of visible tumors. Microscopically the incidence of squamous cell carcinoma and BrdU index were also significantly suppressed by boswellic acid and curcumin.</p><p><b>CONCLUSIONS</b>Both boswellic acid and curcumin were effective in preventing oral carcinogenesis in DMBA-induced hamster cheek pouch model.</p>

Low-dose UVB irradiation stimulates matrix metalloproteinase-1 expression via a BLT2-linked pathway in HaCaT cells

Skin exposure to low-dose ultraviolet B (UVB) light up-regulates the expression of matrix metalloproteinase-1 (MMP-1), thus contributing to premature skin aging (photo-aging). Although cyclooxygenase-2 (COX-2) and its product, prostaglandin E2 (PGE2), have been associated with UVB-induced signaling to MMP expression, very little are known about the roles of lipoxygenases and their products, especially leukotriene B4 (LTB4) and 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE), in MMP-1 expression in skin keratinocytes. In the present study, we demonstrate that BLT2, a cell surface receptor for LTB4 and 12(S)-HETE, plays a critical role in UVB-mediated MMP-1 upregulation in human HaCaT keratinocytes. Moreover, our results demonstrated that BLT2-mediated MMP-1 upregulation occurs through a signaling pathway dependent on reactive oxygen species (ROS) production and the subsequent stimulation of ERK. Blockage of BLT2 via siRNA knockdown or with the BLT2-antagonist LY255283 completely abolished the up-regulated expression of MMP-1 induced by low-dose UVB irradiation. Finally, when HaCaT cells were transiently transfected with a BLT2 expression plasmid, MMP-1 expression was significantly enhanced, along with ERK phosphorylation, suggesting that BLT2 overexpression alone is sufficient for MMP-1 up-regulation. Together, our results suggest that the BLT2-ROS-ERK-linked cascade is a novel signaling mechanism for MMP-1 upregulation in low-dose UVB-irradiated keratinocytes and thus potentially contributes to photo-aging.