Rac1 signaling regulates cigarette smoke-induced inflammation in the lung via the Erk1/2 MAPK and STAT3 pathways.

Cigarette smoke (CS) is a major risk factor for the development of chronic obstructive pulmonary disease (COPD). Our previous studies have indicated that Rac1 is involved in lipopolysaccharide-induced pulmonary injury and CS-mediated epithelial-mesenchymal transition. However, the contribution of Rac1 activity to CS-induced lung inflammation remains not fully clear. In this study, we investigated the regulation of Rac1 in CS-induced pulmonary inflammation. Mice or 16HBE cells were exposed to CS or cigarette smoke extract (CSE) to induce acute inflammation. The lungs of mice exposed to CS showed an increase in the release of interleukin-6 (IL-6) and keratinocyte-derived chemokine (KC), as well as an accumulation of inflammatory cells, indicating high Rac1 activity. The exposure of 16HBE cells to CSE resulted in elevated Rac1 levels, as well as increased release of IL-6 and interleukin-8 (IL-8). Selective inhibition of Rac1 ameliorated the release of IL-6 and KC as well as inflammation in the lungs of CS-exposed mice. Histological assessment showed that treatment with a Rac1 inhibitor, NSC23766, led to a decrease in CD68 and CD11b positive cells and the infiltration of neutrophils and macrophages into the alveolar spaces. Selective inhibition or knockdown of Rac1 decreased IL-6 and IL-8 release in 16HBE cells induced by CSE, which correlated with CSE-induced Rac1-regulated Erk1/2 mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription-3 (STAT3) signaling. Our data suggest an important role for Rac1 in the pathological alterations associated with CS-mediated inflammation. Rac1 may be a promising therapeutic target for the treatment of CS-induced pulmonary inflammation.

Ambroxol inhalation ameliorates LPS-induced airway inflammation and mucus secretion through the extracellular signal-regulated kinase 1/2 signaling pathway.

Ambroxol, a metabolite of bromhexine, is shown to exert several pharmacological activities, including secretolytic, anti-inflammatory and antioxidant actions. Oral and intravenous administration of ambroxol is useful for the airway inflammatory diseases. However, little is known about its potential in inhalation therapy for lipopolysaccharide (LPS)-induced mucous hypersecretion and inflammatory response. In the present study, we compared the pharmacological effects of ambroxol by inhalation with intravenous administration and preliminarily explored its mechanism of action. Our results demonstrated that ambroxol administered by inhalation inhibited MUC5AC expression, reduced glycosaminoglycan levels, enhanced the function of mucociliary clearance and promoted sputum excretion, suggesting that ambroxol increases expectoration of sputum by reducing its viscosity. Moreover, ambroxol significantly alleviated LPS-induced the influx of inflammatory cells and the extracellular signal-regulated kinase 1/2 (Erk 1/2) expression in lung tissues, and inhibited increases in the mRNA expression of the pro-inflammatory cytokines tumor necrosis factor (TNF)-α, CCL-2 (monocyte chemotactic protein-1), KC (keratinocyte cell protein) and interleukin (IL)-1ß in lung tissues. The secretolytic and anti-inflammatory effects of inhaled ambroxol at a dose of 7.5 mg/ml was comparable to that of ambroxol at 20 mg/ml i.v. and dexamethasone at 0.5 mg/kg i.p. In addition, we found that ambroxol dose-dependently inhibited LPS-induced increases in the mRNA expression of MUC5AC, TNF-α, and IL-1ß in human bronchial epithelial cell (NCI-H292) by inhibiting the Erk signaling pathway. These results demonstrate the beneficial effects of ambroxol in inhalation therapy for the airway inflammatory diseases.

EETs Attenuate Ox-LDL-Induced LTB4 Production and Activity by Inhibiting p38 MAPK Phosphorylation and 5-LO/BLT1 Receptor Expression in Rat Pulmonary Arterial Endothelial Cells.

Cytochrome P-450 epoxygenase (EPOX)-derived epoxyeicosatrienoic acids (EETs), 5-lipoxygenase (5-LO), and leukotriene B4 (LTB4), the product of 5-LO, all play a pivotal role in the vascular inflammatory process. We have previously shown that EETs can alleviate oxidized low-density lipoprotein (ox-LDL)-induced endothelial inflammation in primary rat pulmonary artery endothelial cells (RPAECs). Here, we investigated whether ox-LDL can promote LTB4 production through the 5-LO pathway. We further explored how exogenous EETs influence ox-LDL-induced LTB4 production and activity. We found that treatment with ox-LDL increased the production of LTB4 and further led to the expression and release of both monocyte chemoattractant protein-1 (MCP-1/CCL2) and intercellular adhesion molecule-1 (ICAM-1). All of the above ox-LDL-induced changes were attenuated by the presence of 11,12-EET and 14,15-EET, as these molecules inhibited the 5-LO pathway. Furthermore, the LTB4 receptor 1 (BLT1 receptor) antagonist U75302 attenuated ox-LDL-induced ICAM-1 and MCP-1/CCL2 expression and production, whereas LY255283, a LTB4 receptor 2 (BLT2 receptor) antagonist, produced no such effects. Moreover, in RPAECs, we demonstrated that the increased expression of 5-LO and BLT1 following ox-LDL treatment resulted from the activation of nuclear factor-κB (NF-κB) via the p38 mitogen-activated protein kinase (MAPK) pathway. Our results indicated that EETs suppress ox-LDL-induced LTB4 production and subsequent inflammatory responses by downregulating the 5-LO/BLT1 receptor pathway, in which p38 MAPK phosphorylation activates NF-κB. These results suggest that the metabolism of arachidonic acid via the 5-LO and EPOX pathways may present a mutual constraint on the physiological regulation of vascular endothelial cells.

Effects of the inhalation of the m3 receptor antagonist bencycloquidium bromide in a mouse cigarette smoke-induced airway inflammation model.

Bencycloquidium bromide (BCQB), a novel M3 receptor antagonist, alleviates airway hyperresponsiveness, inflammation, and airway remodeling in a murine model of asthma. The aim of this study was to investigate the anti-inflammatory activity of inhaled BCQB in a cigarette smoke (CS)-induced model of acute lung inflammation. Mice exposed to CS developed chronic obstructive pulmonary disease (COPD). Inhalation of BCQB suppressed the accumulation of neutrophils and macrophages in airways and lung and also inhibited the CS-induced increases in mRNA levels of keratinocyte-derived chemokine, monocyte chemotactic protein-1, tumor necrosis factor-alpha, and interleukin-1ß in lung and protein expression levels in bronchoalveolar lavage fluid. Moreover, BCQB (300 µg/ml) inhibited the CS-induced changes in superoxide dismutase and myeloperoxidase activities in the lungs. Our study suggests that BCQB might be a potential therapy for inflammation in CS-induced pulmonary diseases, including COPD.

Ciclamilast ameliorates adjuvant-induced arthritis in a rat model.

We assessed the effect of a novel and selective phosphodiesterase 4 (PDE4) inhibitor, ciclamilast, on chronic inflammation in adjuvant-induced arthritis (AIA), a rat model of rheumatoid arthritis (RA), and acute inflammation in the rat and mouse model of carrageenan-induced paw edema and peritonitis. Our results showed that daily oral administration of ciclamilast at 1, 3, and 10 mg/kg dose-dependently inhibited the increase in hind paw volume of rats with AIA. The inhibition of paw edema was associated with inhibition of both the production of cytokines such as TNF-α, IL-1ß, and IL-6 and cell infiltration assessed in subcutaneous paw tissue. Moreover, there was significantly less tissue destruction in the ciclamilast-treated rats compared to the vehicle-treated rats, as assessed by radiographic analysis and histopathological evaluation. In the two acute inflammation models, ciclamilast inhibited carrageenan-induced paw edema in rats and inflammatory cell migration into the peritoneal cavity in mice in a dose-dependent manner. These results not only suggest that ciclamilast, as a disease-modifying antirheumatic drug (DMARD), can attenuate RA but also provide proof of principle that a PDE4 inhibitor may be useful for the treatment of arthritis.

Cigarette smoke extract-induced BEAS-2B cell apoptosis and anti-oxidative Nrf-2 up-regulation are mediated by ROS-stimulated p38 activation.

Cigarette smoke contains reactive oxygen (ROS) that can cause oxidative stress. It increases the number of apoptotic and necrotic lung cells and further induces the development of chronic airway disease. In this study, we investigated the effects of cigarette smoke extract (CSE) on apoptosis in human bronchial epithelial cells (BEAS-2B). CSE exposure induced ROS generation and p38 mitogen-activated protein kinase (MAPK) activation that are associated with the activation of apoptosis-regulating signal kinase 1 (ASK-1). N-acetylcysteine (a general antioxidant) attenuated the CSE-induced ASK-1 and p38 MAPK activation and cell apoptosis, suggesting a triggering role of ROS in ASK-1/p38 MAPK activation during apoptotic progression. In contrast, the inhibition and knockdown of p38 attenuated the expression of anti-oxidant master NF-E2-related factor 2 (Nrf-2) and CSE-induced apoptosis, suggesting that p38 MAPK modulates Nrf-2 expression and presumably prevents cell apoptosis. Taken together, the data presented in this manuscript demonstrate that the ROS-dependent ASK-1/p38 signaling cascade regulates CSE-induced BEAS-2B cell apoptosis. In addition, anti-oxidative Nrf-2 is also up-regulated by the ROS/p38 signaling cascade in this progression.

EETs alleviate ox-LDL-induced inflammation by inhibiting LOX-1 receptor expression in rat pulmonary arterial endothelial cells.

Oxidized low-density lipoprotein (Ox-LDL) is associated with atherosclerotic events through the modulation of arachidonic acid (AA) metabolism and activation of inflammatory signaling. Cytochrome P450 (CYP) epoxygenase-derived epoxyeicosatrienoic acids (EETs) mitigate inflammation through nuclear factor-κB (NF-κB). In this study, we explored the effects and mechanisms of exogenous EETs on the ox-LDL-induced inflammation of pulmonary artery endothelial cells (PAECs), which were cultured from rat pulmonary arteries. We determined that pre-treatment with 11,12-EET or 14,15-EET attenuated the ox-LDL-induced expression and release of intercellular adhesion molecule-1 (ICAM-1), E-selectin, and monocyte chemoattractant protein-1 (MCP-1) in a concentration-dependent manner. In addition, the ox-LDL-induced expression of CYP2J4 was upregulated by 11,12-EET and 14,15-EET (1µM). Furthermore, the endothelial receptor of lectin-like oxidized low-density lipoprotein (LOX-1) was downregulated in PAECs treated with EETs. The inflammatory responses evoked by ox-LDL (100µg/mL) were blocked by pharmacological inhibitors of Erk1/2 mitogen-activated protein kinase (MAPK) (U0126), p38 MAPK (SB203580), and NF-κB (PDTC). In addition, we confirmed that 11,12-EET suppresses phosphorylation of p38, degradation of IκBα, and activation of NF-κB (p65), whereas 14,15-EET can significantly suppress the phosphorylation of p38 and Erk1/2. Our results indicate that EETs exert beneficial effects on ox-LDL-induced inflammation primarily through the inhibition of LOX-1 receptor upregulation, MAPK phosphorylation, and NF-κB activation and through the upregulation of CYP2J4 expression. This study helps focus the current understanding of the contribution of EETs to the regulation of the inflammation of pulmonary vascular endothelial cells. Furthermore, the therapeutic potential of targeting the EET pathway in pulmonary vascular disease will be highlighted.

Cigarette smoke-induced alveolar epithelial-mesenchymal transition is mediated by Rac1 activation.

BACKGROUND: Epithelial-mesenchymal transition (EMT) is the major pathophysiological process in lung fibrosis observed in chronic obstructive pulmonary disease (COPD) and lung cancer. Smoking is a risk factor for developing EMT, yet the mechanism remains largely unknown. In this study, we investigated the role of Rac1 in cigarette smoke (CS) induced EMT. METHODS: EMT was induced in mice and pulmonary epithelial cells by exposure of CS and cigarette smoke extract (CSE) respectively. RESULTS: Treatment of pulmonary epithelial cells with CSE elevated Rac1 expression associated with increased TGF-ß1 release. Blocking TGF-ß pathway restrained CSE-induced changes in EMT-related markers. Pharmacological inhibition or knockdown of Rac1 decreased the CSE exposure induced TGF-ß1 release and ameliorated CSE-induced EMT. In CS-exposed mice, pharmacological inhibition of Rac1 reduced TGF-ß1 release and prevented aberrations in expression of EMT markers, suggesting that Rac1 is a critical signaling molecule for induction of CS-stimulated EMT. Furthermore, Rac1 inhibition or knockdown abrogated CSE-induced Smad2 and Akt (PKB, protein kinase B) activation in pulmonary epithelial cells. Inhibition of Smad2, PI3K (phosphatidylinositol 3-kinase) or Akt suppressed CSE-induced changes in epithelial and mesenchymal marker expression. CONCLUSIONS AND GENERAL SIGNIFICANCE: Altogether, these data suggest that CS initiates EMT through Rac1/Smad2 and Rac1/PI3K/Akt signaling pathway. Our data provide new insights into the fundamental basis of EMT and suggest a possible new course of therapy for COPD and lung cancer.

A C 21 -Steroidal Glycoside Isolated from the Roots of Cynanchum auriculatum Induces Cell Cycle Arrest and Apoptosis in Human Gastric Cancer SGC-7901 Cells.

Caudatin 3-O-ß-D-cymaropyranosyl-(1 → 4)-ß-D-oleandropyranosyl-(1 → 4)-ß-D-cymaropyranosyl-(1 → 4)-ß-D-cymaropyranoside (CGII) is one of the C21-steroidal glycosides isolated from the roots of Cynanchum auriculatum ROYLE ex WIGHT. This study aimed to determine the cell growth, cell proliferation, and apoptotic cell death of human gastric cancer cells after CGII treatment. MTT assay was used to determine cell growth; fluorescence-activated cell sorting analysis was used to evaluate cell cycle distribution and apoptotic cell death. Immunoblotting was applied for measuring the expression of proteins involved in the cell cycle progression. The activities of caspase-3, -8, and -9 were detected by colorimetric caspase activity assays. CGII inhibited cell growth of human gastric cancer SGC-7901 cells in a concentration- and time-dependent manner. Treatment of SGC-7901 cells with CGII resulted in G1 phase cell cycle arrest, accompanied with decreased expression of cyclin D1 and cyclin-dependent kinases 4 and 6. CGII induced cell apoptosis and activated caspase-3, caspase-8, and caspase-9. In contrast, pan-caspase inhibitor z-VAD-fmk partially abolished the CGII-induced growth inhibition of SGC-7901 cells. In conclusion, CGII inhibits cell growth of human gastric cancer cells by inducing G1 phase cell cycle arrest and caspase-dependent apoptosis cascades.

Intracerebroventricular injection of leukotriene B4 attenuates antigen-induced asthmatic response via BLT1 receptor stimulating HPA-axis in sensitized rats.

BACKGROUND: Basic and clinical studies suggest that hypothalamic-pituitary-adrenal (HPA) axis is the neuroendocrine-immune pathway that functionally regulates the chronic inflammatory disease including asthma. Our previous studies showed corresponding changes of cytokines and leukotriene B4 (LTB4) between brain and lung tissues in antigen-challenged asthmatic rats. Here, we investigated how the increased LTB4 level in brain interacts with HPA axis in regulating antigen-induced asthmatic response in sensitized rats. METHODS: Ovalbumin-sensitized rats were challenged by inhalation of antigen. Rats received vehicle, LTB4 or U75302 (a selective LTB4 BLT1 receptor inhibitor) was given via intracerebroventricular injection (i.c.v) 30 min before challenge. Lung resistance (RL) and dynamic lung compliance (Cdyn) were measured before and after antigen challenge. Inflammatory response in lung tissue was assessed 24 h after challenge. Expression of CRH mRNA and protein in hypothalamus were evaluated by RT-PCR and Western Blot, and plasma levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were measured using the ELISA kits. RESULTS: Antigen challenge decreased pulmonary function and induced airway inflammation, evoked HPA axis response in sensitized rats. Administration of LTB4 via i.c.v markedly attenuated airway contraction and inflammation. Meanwhile, LTB4 via i.c.v markedly increased CORT and ACTH level in plasma before antigen challenge, and followed by further increases in CORT and ACTH levels in plasma after antigen challenge in sensitized rats. Expression of CRH mRNA and protein in hypothalamus were also significantly increased by LTB4 via i.c.v in sensitized rats after antigen challenge. These effect were completely blocked by pre-treatment with BLT1 receptor antagonist U75302 (10 ng), but not by BLT2 antagonist LY255283. CONCLUSIONS: LTB4 administered via i.c.v down-regulates the airway contraction response and inflammation through activation of the HPA axis via its BLT1 receptor. This study expands our concept of the regulatory role of intracranial inflammatory mediators in inflammatory diseases including asthma. The favourable effects of LTB4 on the HPA axis may help to explain the phenomenon of self-relief after an asthmatic attack.

[Inhibitory effects of an antisense PCDGF vector on proliferation and invasion of highly malignant ovarian cancer cells and the related mechanism].

OBJECTIVE: To investigate the inhibitory effects of an antisense PC cell derived growth factor (PCDGF) vector on proliferation and invasion of highly malignant ovarian cancer cell lines Sw626 and A2780 cells, and preliminarily explore the related mechanisms. METHODS: MTT assay and Boyden chamber in vitro invasion assay were employed to detect the changes of proliferation and invasion ability in the Sw626 and A2780 cells transfected with anti-sense PCDGF. The expression levels of cyclin D1 and CDK4 proteins before and after transfection were detected by Western blotting. The effects on the expression and activity of MMP-2 were evaluated by quantitative RT-PCR and zymography, respectively. RESULTS: Comparing with the blank group, the proliferation inhibition rate of the Sw626 and A2780 cells transfected with anti-sense PCDGF was 72.9% and 70.9%, respectively, and the invasion ability was inhibited by 62.9% and 59.0%, respectively. The levels of cyclin D1 and CDK4 protein expression in antisense PCDGF transfected cells were 0.38 +/- 0.08 and 0.37 +/- 0.13, respectively, all significantly lower than 0.84 +/- 0.11 and 0.64 +/- 0.11, respectively, in the blank group (P < 0.01). The MMP-2 mRNA expression level in antisense PCDGF transfected cell group was 0.66 +/- 0.11, not significantly decreased in comparison with 0.89 +/- 0.09 in the blank group (P > 0.05), but the activity of MMP-2 was inhibited significantly. CONCLUSION: The antisense PCDGF vector may inhibit markedly the proliferation and invasion of highly malignant ovarian cancer cells, and partially reverses their malignant phenotype. It seems to be related with down-regulating the expression of cyclin D1 and CDK4 and inhibiting the activity of MMP-2. Our findings indicate that PCDGF may become a new target for antisense gene therapy of ovarian cancer.

Oral administration of allergen extracts from Dermatophagoides farinae desensitizes specific allergen-induced inflammation and airway hyperresponsiveness in rats.

Clinically sublingual immunotherapy (SLIT) by using allergen extracts effectively alleviates the symptoms of allergic rhinitis and asthma. Supposed that oral administration of high-dose of allergen extracts imitates SLIT and may prevent IgE-related responses in allergic diseases, we investigated the effects of oral administration of allergen extracts from Dermatophagoides farinae (Derf) on allergen-induced inflammation and airway hyperresponsiveness (AHR) in a model of asthmatic rat. After administration to the specific Derf-sensitized rats with Derfdrop solution containing Derf1 and Derf2 extracts derived from Derf, the effects of Derfdrop on AHR, inflammatory cell accumulation, cytokine production in the bronchoalveolar lavage fluid and lung tissue, as well as serum IgE and IgG levels were investigated. Results indicated that Derfdrop not only dose-dependently prevented the AHR in response to methacholine, but also significantly reduced the serum total and allergen-specific IgE levels, all the maximal effects were achieved at dose of 5 mg/kg/d, and were as comparable as those of dexamethasone at dose of 1.0 mg/kg/d. Furthermore, oral administration of Derfdrop not only dose-dependently elevated allergen-specific serum IgG levels and reduced total and allergen-specific IgE levels, but also normalized the imbalance between the Th1 cytokine, IFN-gamma and Th2 cytokine, IL-4. Finally, oral administration of Derfdrop significantly reduced Goblet cell hyperplasia and eosinophilia in the Derf-sensitized allergic rat model. These data suggest that Derfdrop effectively improves specific allergen-induced inflammation and AHR in Derf-sensitized and -challenged rats and provide with the rationale for clinical SLIT by using Derfdrop in a specific allergen-induced asthma.

[Inhibitory effects of BIO-1211 on bronchoconstriction and neutrophil adhesion in rats].

OBJECTIVE: To determine the inhibitory effects of BIO-1211, a very late antigen-4 (vla-4) antagonist, on bronchoconstriction and neutrophil adhesion in rats. METHODS: For evaluating ovalbumin-induced bronchoconstriction in the sensitized rats, the changes in lung resistance (RL) and lung dynamic compliance (C(dyn)) were determined after antigen challenge. Neutrophils from the rats were used to determine fibronectin and serum-induced cell adhesion. The effect of BIO-1211 on wheezing was determined after inhalation of histamine and acetylcholine in guinea pigs. RESULT: BIO-1211 aerosol at 1, 3 and 10 mg/ml significantly inhibited the changes in lung resistance and lung dynamic compliance after antigen challenge in the sensitized rats in a dose-dependent manner. BIO-1211 at 25, 50, 100 and 200 microgram/ml inhibited the fibronectin-induced neutrophil adhesion by 23.5%, 24.6%, 61.4% and 58.1%, respectively, and serum-induced adhesion by 29.9%, 35.9%, 35.3% and 15.4%, respectively. Inhalation of 10 mg/ml BIO-1211 did not show any protection against histamine and acetylcholine-induced bronchoconstriction. CONCLUSION: BIO-1211 inhibits bronchoconstriction and neutrophil adhesion, which may be associated with its effect against bronchoconstriction in rats.

Anti-asthmatic effects of Perilla seed oil in the guinea pig in vitro and in vivo.

The aim of this study was to investigate the anti-asthmatic effects of Perilla seed oil in vitro and in vivo in sensitized guinea pigs. Aerosolized antigen caused an immediate bronchoconstriction. Perilla seed oil per os inhibited the increase in lung resistance and the decrease in dynamic lung compliance in a dose-dependent manner with an ED50 (95 % confidence interval, CI) of 1.10 (0.98 - 1.24) g/kg and 1.07 (0.94 - 1.22) g/kg, respectively. Infiltration of leukocytes, mononuclear cells, eosinophils and neutrophils induced by inhaling antigen was also inhibited by Perilla seed oil in a dose-dependent manner with an ED50 (95 % CI) of 1.00 (0.86 - 1.15), 1.24 (1.10 - 1.38), 0.63 (0.51 - 0.77) and 0.61 (0.38 - 0.98) g/kg, respectively. Perilla seed oil (5 - 500 microg/mL) inhibited the slow reaction substance of anaphylaxis (SRS-A) release induced by antigen challenge in lung tissue of sensitized guinea pigs. It also inhibited calcium ionophore (A(23187))-induced leukotriene (LT) D4 release from the lung tissue of non-sensitized guinea pigs in a concentration-dependent manner with an IC50 (95 % CI) of 50 (36 - 69) microg/mL. These results indicate that Perilla seed oil may improve lung function in asthma by controlling eicosanoid production and suppressing LT generation.

Changes of 5-lipoxygenase pathway and proinflammatory mediators in cerebral cortex and lung tissue of sensitized rats.

AIM: To explore the change of 5-lipoxygenase (5-LO) pathway expression and proinflammatory mediators level of lung tissue and cerebral cortex, and the possible regulatory mechanism through central nervous 5-LO pathways to pulmonary inflammatory status in antigen repeated challenged rats. METHODS: Four groups of rats were treated as control, asthma model, asthma model treatment with dexamethasone (DXM, 0.5 mg/kg, i.p.) and ketotifen (5 mg/kg, i.g.). Tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, interferon (IFN)-gamma, and nitric oxide (NO) were detected by ELISA kits. The mRNA expression of 5-LO and LTA4-hydrolase (LTA4-H) was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), and the protein content of 5-LO was measured by Western blot. RESULTS: Increase of TNF-alpha, IL-4, NO level, and decrease of IFN-gamma level in bronchoalveolar lavage fluid (BALF) and cerebral cortex in sensitized rats were shown after repeated antigen challenge. The expression of 5-LO and LTA4-H mRNA, and 5-LO protein levels were increased in lung tissue and cerebral cortex in asthma rats. In comparison with the asthma model, DXM significantly inhibited the increase of cytokine levels and the expression of 5-LO pathway enzyme (P<0.05). Ketotifen also inhibited the increase of TNF-alpha level and 5-LO pathway enzyme expression in lung and cerebral cortex, but had no effect on the level of NO, IL-4, and IFN-gamma. CONCLUSION: The correlative increase of 5-LO pathway enzyme expression and proinflammatory mediators of brain may have a regulatory effect on pulmonary inflammation in asthma.