Pulmonary hypertension secondary to seronegative rheumatoid arthritis overlapping antisynthetase syndrome: A case report.

BACKGROUND: Polyarthritis is the most frequent clinical manifestation in antisynthetase syndrome (ASS) forms of idiopathic inflammatory myositis and may be misdiagnosed as rheumatoid arthritis (RA), particularly in patients with seronegative RA (SNRA). It is unclear whether there is an overlap between ASS and RA, or if ASS sometimes mimics RA. Pulmonary hypertension (PAH) is common in connective tissue diseases (CTDs). However, published reports on CTD-PAH do not include overlapping CTDs, and its incidence and impact on patient prognosis are unclear. CASE SUMMARY: We report the case of a 63-year-old woman who presented with a 3-mo history of symptom aggravation of recurrent symmetrical joint swelling and pain that had persisted for over 10 years. The patient was diagnosed with RA and interstitial lung disease. The patient repeatedly presented to the hospital's respiratory and rheumatology departments with arthralgia, plus shortness of breath after activity. Relevant tests indicated that anti-CCP and RF remained negative, while anti-J0-1 and anti-Ro-52 were strongly positive. It was not until recently that we recognized that this could be an unusual case of SNRA with concurrent ASS. Joint pain was relieved after regular anti-rheumatic treatment. Chest computed tomography scans showed that pulmonary interstitial changes did not progress significantly over several years; however, they showed gradual widening of the pulmonary artery, and cardiac ultrasound indicated elevated pulmonary artery systolic pressure. The prescribed treatment of PAH was not effective in improving shortness of breath. CONCLUSION: Overlap of RA and ASS may be missed. Further research is necessary to facilitate early diagnosis, effective evaluation, and prognosis.

Clinical features and risk factors associated with severe COVID-19 patients in China.

BACKGROUND: Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly spread throughout the world. In this study, we aimed to identify the risk factors for severe COVID-19 to improve treatment guidelines. METHODS: A multicenter, cross-sectional study was conducted on 313 patients hospitalized with COVID-19. Patients were classified into two groups based on disease severity (nonsevere and severe) according to initial clinical presentation. Laboratory test results and epidemiological and clinical characteristics were analyzed using descriptive statistics. Univariate and multivariate logistic regression models were used to detect potential risk factors associated with severe COVID-19. RESULTS: A total of 289 patients (197 nonsevere and 92 severe cases) with a median age of 45.0 (33.0, 61.0) years were included in this study, and 53.3% (154/289) were male. Fever (192/286, 67.1%) and cough (170/289, 58.8%) were commonly observed, followed by sore throat (49/289, 17.0%). Multivariate logistic regression analysis suggested that patients who were aged ≥ 65 years (OR: 2.725, 95% confidence interval [CI]: 1.317-5.636; P = 0.007), were male (OR: 1.878, 95% CI: 1.002-3.520, P = 0.049), had comorbid diabetes (OR: 3.314, 95% CI: 1.126-9.758, P = 0.030), cough (OR: 3.427, 95% CI: 1.752-6.706, P < 0.001), and/or diarrhea (OR: 2.629, 95% CI: 1.109-6.231, P = 0.028) on admission had a higher risk of severe disease. Moreover, stratification analysis indicated that male patients with diabetes were more likely to have severe COVID-19 (71.4% vs. 28.6%, χ2 = 8.183, P = 0.004). CONCLUSIONS: The clinical characteristics of those with severe and nonsevere COVID-19 were significantly different. The elderly, male patients with COVID-19, diabetes, and presenting with cough and/or diarrhea on admission may require close monitoring to prevent deterioration.

Unexplained elevation of erythrocyte sedimentation rate in a patient recovering from COVID-19: A case report.

BACKGROUND: A disease caused by a novel coronavirus virus, named coronavirus disease 2019 (COVID-19), broke out in Wuhan, China in December 2019, and spread around the word. As of March 4, 2020, 93090 confirmed cases and 2984 deaths have been reported in more than 80 countries and territories. It has triggered global public health security. However, the features and prognosis of COVID-19 are incompletely understood. CASE SUMMARY: We here report that the erythrocyte sedimentation rate (ESR) increased in a confirmed COVID patient. The high level of ESR sustained for a long time even after the patient recovered from COVID-19, while all results related to tumor, tuberculosis, rheumatic diseases, anemia, etc. cannot explain the abnormal elevation of ESR presented in this case. CONCLUSION: Although the increased ESR cannot be explained by all existing evidence, it possibly links the abnormal pathologic change in some COVID-19 patients and negative prognosis, and provides the clue to dissect the mechanism of illness progressing in COVID-19 and its prognosis.

[Effect of Curcumin on TGF-ß2 Regulated PPAR-γ/PDGF-ß Signaling Pathway in Lung Fibroblasts of Mice].

OBJECTIVE: To explore the effect of curcumin on TGF-ß2 regulated peroxisome proliferater activated receptor y (PPAR-γ)/platelet derived growth factor ß (PDGF-ß) signaling pathway in lung fibroblasts of mice. METHODS: C57BL/6 mouse lung fibroblasts were in vitro cultured with TGF-ß2, curcumin, or TGF-ß2 plus curcumin. The cell proliferation was detected by cell growth counting in the blank control group, low, middle, and high dose curcumin groups (5, 25, 50 µmol/L), the TGF-ß2 (10 ng/mL) group, TGF-ß2 (10 ng/mL) plus curcumin (5, 25, 50 µmol/L) groups. mRNA expressions of PPAR-γ, platelet-derived growth factor receptor ß (PDGFR-ß), fibroblast growth factor R1 (FGFR1) were detected using reverse transcription PCR. Protein levels of PPAR-γ and collagen-1 were detected using Western blot and ELISA in the blank control group, the TGF-ß2 group, the TGF-ß2 (10 ng/mL) plus curcumin 50 µmol/L group. RESULTS: Compared with the blank control group, curcumin 50 µmol/L showed the most significant inhibition on cell proliferation at 48 h and 72 h. Compared with the TGF-ß2 group, TGF-ß2 (10 ng/mL) plus curcumin 50 mol/L also showed the most significant inhibition on cell proliferation at 48 h and 72 h. Compared with the blank control group, mRNA expressions of PPAR-γ and PDGF-ß, as well as protein expression of PPAR-γ increased, the collagen-1 expression also increased in the TGF-ß2 group (P < 0.05). Compared with the TGF-ß2 group, mRNA expressions of PPAR-γ obviously increased in the TGF-ß2 (10 ng/mL) plus curcumin 25 µmol/L group and the TGF-ß2 (10 ng/mL) plus curcumin 50 µmol/L group, higher than that in the TGF-ß2 (10 ng/mL) plus curcumin 5 [µmol/L group (P < 0.05). mRNA expressions of PPAR-γ was higher in the TGF-ß2 (10 ng/mL) plus curcumin 50 µmol/L group than in the TGF-ß2 (10 ng/mL) plus curcumin 25 µmol/L group (P < 0.05). mRNA expressions of PDGF-ß was lower in TGF-ß2 (10 ng/mL) plus curcumin groups than in the TGF-ß2 group (P < 0.05). Besides, PDGF-ß mRNA expressions were lower in the TGF-ß2 (10 ng/mL) plus curcumin 50 µmol/L group than in the TGF-ß2 (10 ng/mL) plus curcumin 5 µmol/L group and the TGF-ß2 (10 ng/mL) plus curcumin 25 µmol/L group (P < 0.05). There was no statistical difference in FGFR1 mRNA expressions between the TGF-ß2 group and 3 TGF-ß2 plus curcumin groups (P > 0.05). Compared with the TGF-ß2 group, PPAR-γ protein expressions increased and collagen-1 protein expressions decreased in the TGF-ß2 (10 ng/mL) plus curcumin 50 µLmol/L group (P < 0.05, P < 0.01). CONCLUSIONS: Curcumin not only could inhibit TGF-ß2 induced proliferation of lung fibroblasts, but also could inhibit the synthesis of collagens. These might be associated with up-regulating PPAR-γ expressions and down-regulating PDGF-ß expressions. Therefore, curcumin might inhibit the occurrence and developing of lung fibrosis through blocking PPAR-γ/PDGF-ß signaling pathway.

Doxycycline attenuates acrolein-induced mucin production, in part by inhibiting MMP-9.

Matrix metalloproteinases (MMPs), especially MMP-9, have been found to increase the expression of epidermal growth factor (EGF) receptor, a possible regulator of acrolein-induced mucin expression in the airway epithelium. The aim of this study was to investigate whether doxycycline, a tetracycline antibiotic that inhibits MMPs, attenuates mucus production and synthesis of mucin MUC5AC in acrolein-exposed rats. Sprague-Dawley rats were exposed to acrolein aerosol [3.0parts/million (ppm), 6h/day, 12days] and they received 20mg/kg doxycycline daily by gavage, beginning two days before exposure to acrolein until the end of the experiment. The production of mucin glycoproteins and expression of the MMP-9 and MUC5AC genes were measured in rat trachea. The increase in levels of MMP-9 mRNA and protein in airway epithelium after acrolein exposure was accompanied by an increase in MUC5AC mRNA expression. Doxycycline significantly prevented these increases in acrolein-induced expression of MMP-9 and MUC5AC and attenuated mucus production in tracheal epithelium. These results indicate that doxycycline attenuated acrolein-induced mucin synthesis, in part by inhibiting expression of MMP-9. Thus doxycycline may have a prophylactic effect in the treatment of smoking-induced mucus hypersecretion.

Effect of budesonide on TGF-beta1-enhanced VEGF production by lung fibroblasts.

VEGF (vascular endothelial growth factor) is a potent proangiogenic cytokine, and vascular change is one of the characteristic features of airway remodelling. Since the glucocorticoids have shown antifibrosis properties, we sought to investigate whether budesonide, a widely used glucocorticoid in clinical practice, could attenuate TGF-beta1 (transforming growth factor-beta1)-induced VEGF production by HFL-1 (human lung fibroblasts). HFL-1 fibroblasts were treated with various concentrations of budesonide (10(-11) M, 10(-9) M and 10(-7) M) in the absence or presence of TGF-beta1. Postculture media were collected for ELISA of VEGF at the indicated times. The cell lysates were subjected to Western blotting analysis to test TGF-beta1/Smad and MAP (mitogen-activated protein) kinase signalling activation, respectively. The results suggested that budesonide pretreatment reduced the significant increase of VEGF release induced by TGF-beta1 in HFL-1 fibroblasts in a dose-dependent manner, and suppressed the increase of phospho-Smad3 and phosphor-ERK (extracellular signal-regulated kinase) protein levels. In conclusion, budesonide may reduce TGF-beta1-induced VEGF production in the lung, probably through the Smad/ERK signalling pathway and, thus, may provide new sight into the molecular mechanism underlying glucocorticoid therapy for airway inflammatory diseases.

Simvastatin attenuates acrolein-induced mucin production in rats: involvement of the Ras/extracellular signal-regulated kinase pathway.

Airway mucus overproduction is a cardinal feature of airway inflammatory diseases, such as chronic obstructive pulmonary disease and cystic fibrosis. Since the small G-protein Ras is known to modulate cellular functions in the lung, we sought to investigate whether the Ras inhibitor simvastatin could attenuate acrolein-induced mucin production in rat airways. Rats were exposed to acrolein for 12 days, after first being pretreated intragastrically for 24 h with either simvastatin alone or simvastatin in combination with mevalonate, which prevents the isoprenylation needed for Ras activation. Lung tissue was analyzed for extracellular signal-regulated kinase (ERK) activity, goblet cell metaplasia and mucin production. To analyze the effect of simvastatin on mucin production in more detail, acrolein-exposed human airway epithelial NCI-H292 cells were pretreated with simvastatin alone or together with mevalonate. Culture medium was collected to detect mucin secretion, and cell lysates were examined for Ras-GTPase activity and epidermal growth factor receptor (EGFR)/ERK phosphorylation. In vivo, simvastatin treatment dose-dependently suppressed acrolein-induced goblet cell hyperplasia and metaplasia in bronchial epithelium and inhibited ERK phosphorylation in rat lung homogenates. Moreover, simvastatin inhibited Muc5AC mucin synthesis at both the mRNA and protein levels in the lung. In vitro, simvastatin pretreatment attenuated the acrolein-induced significant increase in MUC5AC mucin expression, Ras-GTPase activity and EGFR/ERK phosphorylation. These inhibitory effects of simvastatin were neutralized by mevalonate administration both in vitro and in vivo. Our results suggest that simvastatin may attenuate acrolein-induced mucin protein synthesis in the airway and airway inflammation, possibly by blocking ERK activation mediated by Ras protein isoprenylation. Thus, the evidence from the experiment suggests that human trials are warranted to determine the potential safety and efficacy of simvastatin for treatment of over production of airway mucus.

Effects of single nucleotide polymorphisms 869 T/C and 915 G/C in the exon 1 locus of transforming growth factor-beta1 gene on chronic obstructive pulmonary disease susceptibility in Chinese.

BACKGROUND: The main risk factor for chronic obstructive pulmonary disease (COPD) is cigarette smoking. However, only 10% - 20% of chronic heavy smokers develop systematic COPD. We hypothesized that the inheritance of gene polymorphisms could influence the development of COPD, which was investigated by studying two single nucleotide polymorphisms (SNP) in exon 1 of the transforming growth factor-beta1 (TGF-beta1) gene. METHODS: We enrolled 219 patients with COPD as the research group and 148 healthy people as the control group, all of whom were Chinese Han people. The polymorphisms of the TGF-beta1 gene, 869T/C and 915G/C, were analyzed using the method of amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). RESULTS: The occurrence of the TGF-beta1 gene 869T/C polymorphism in patients with COPD was significantly different from the control group (P < 0.05), in which the relative risk of this disease increased in cases who had the C allele (OR: 1.131, 95%CI: 1.101 - 1.539). There was no increased frequency of TGF-beta1 915G/C gene in COPD patients compared with control subjects (P > 0.05). CONCLUSIONS: The polymorphism 869T/C in TGF-beta1 gene has a significant association with disease occurrence in COPD patients and the C allele might be a risk factor. The homozygous wild-type CC of 869T/C on TGFbeta1 could be a predisposing factor in COPD and those who carry the C allele might have particularly susceptibility to developing COPD.

Simvastatin attenuates experimental small airway remodelling in rats.

BACKGROUND AND OBJECTIVE: The aim of this study was to assess the beneficial effects of simvastatin on cigarette smoke-induced small airway remodeling in rats. METHODS: Simvastatin was administered at different doses for 16 weeks to rats with cigarette smoke-induced small airway remodelling. Morphological analyses were performed, and collagen deposition, production of growth factors, inflammatory parameters and RhoA, as well as the Smad signalling pathway in the lungs, were examined. RESULTS: Simvastatin attenuated small airway wall thickening and prevented the increase in lung hydroxyproline content and collagen deposition induced in airway walls by cigarette smoking. In addition, simvastatin downregulated transforming growth factor-beta1 and connective tissue growth factor protein and gene expression in the lungs. Furthermore, accumulation of macrophages and neutrophils and increases in tumour necrosis factor-alpha concentration in BAL fluid were inhibited by simvastatin. Simultaneously, the expression of RhoA and the phosphorylation of Smad2 and Smad3 in lungs exposed to cigarette smoke were inhibited during simvastatin administration. However, the increased expression of Smad2 and Smad3 proteins and the decreased level of Smad7 protein in remodelled lungs were not affected by simvastatin. CONCLUSIONS: Simvastatin attenuated experimental small airway remodelling, as indicated by decreases in collagen deposition and small airway wall thickening. Simvastatin may inhibit cigarette smoke-induced small airway remodelling by reducing growth factor expression and inflammation. The mechanism of action of simvastatin on small airway remodelling involved RhoA and the Smad signalling pathway. These findings indicate that simvastatin may have potential beneficial effects in the treatment of COPD.

p38 MAPK and MMP-9 cooperatively regulate mucus overproduction in mice exposed to acrolein fog.

OBJECTIVE: To evaluate the role of p38 mitogen-activated protein kinase (MAPK) on mice airway inflammation, mucus production and the possible cross-talk between p38 MAPK and matrix metalloproteinase-9 (MMP-9) in mucin protein synthesis. METHODS: Mice were exposed to 4.0 ppm of acrolein for 21 days with daily intraperitoneal injection of SB203580, a specific inhibitor of p38 MAPK. In control mice, sterile saline was administered instead. On days 7 and 21, mice were sacrificed to examine airway inflammation and mucus production by BALF cell counts, cytokine ELISA, and H&E and AB-PAS staining. The mRNA and protein levels of Muc5ac, p38 MAPK and MMP-9 in the lung were determined by RT-PCR, immunohistochemistry and Western blotting analysis. MMP-9 activity was measured by gelatin zymography. RESULTS: Both the numbers of inflammatory cells and mucus-secreting goblet cells were significantly increased in the airways of mice exposed to acrolein as compared to the control mice. Acrolein-increased phosphorylation of p38 MAPK was significantly reduced by SB203580. The airway inflammation and goblet cell hyperplasia after acrolein challenge were also attenuated by SB203580 administration. Moreover, SB203580 treatment decreased the acrolein-induced increase of Muc5ac and MMP-9 expression and MMP-9 activity in airway epithelium. CONCLUSIONS: The results indicate an important role of p38 MAPK in acrolein-induced airway inflammation and mucus hypersecretion in mice. The cooperation of p38 and MMP-9 may contribute to the mucin overproduction after inflammatory challenge.

Blockade of advanced glycation end product formation attenuates bleomycin-induced pulmonary fibrosis in rats.

BACKGROUND: Advanced glycation end products (AGEs) have been proposed to be involved in pulmonary fibrosis, but its role in this process has not been fully understood. To investigate the role of AGE formation in pulmonary fibrosis, we used a bleomycin (BLM)-stimulated rat model treated with aminoguanidine (AG), a crosslink inhibitor of AGE formation. METHODS: Rats were intratracheally instilled with BLM (5 mg/kg) and orally administered with AG (40, 80, 120 mg/kg) once daily for two weeks. AGEs level in lung tissue was determined by ELISA and pulmonary fibrosis was evaluated by Ashcroft score and hydroxyproline assay. The expression of heat shock protein 47 (HSP47), a collagen specific molecular chaperone, was measured with RT-PCR and Western blot. Moreover, TGFbeta1 and its downstream Smad proteins were analyzed by Western blot. RESULTS: AGEs level in rat lungs, as well as lung hydroxyproline content and Ashcroft score, was significantly enhanced by BLM stimulation, which was abrogated by AG treatment. BLM significantly increased the expression of HSP47 mRNA and protein in lung tissues, and AG treatment markedly decreased BLM-induced HSP47 expression in a dose-dependent manner (p < 0.05). In addition, AG dose-dependently downregulated BLM-stimulated overexpressions of TGFbeta1, phosphorylated (p)-Smad2 and p-Smad3 protein in lung tissues. CONCLUSION: These findings suggest AGE formation may participate in the process of BLM-induced pulmonary fibrosis, and blockade of AGE formation by AG treatment attenuates BLM-induced pulmonary fibrosis in rats, which is implicated in inhibition of HSP47 expression and TGFbeta/Smads signaling.

Rosiglitazone, a peroxisome proliferator-activated receptor-gamma agonist, attenuates acrolein-induced airway mucus hypersecretion in rats.

BACKGROUND: Peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a member of the ligand-activated nuclear receptor superfamily, has been shown to be implicated in anti-inflammatory and immunomodulatory responses, but its role in airway mucus hypersecretion remains not clear. OBJECTIVE: To investigate the role of PPAR-gamma in airway mucus hypersecretion, we used an acrolein-exposed rat model treated with rosiglitazone, a peroxisome proliferator-activated receptor-gamma agonist. METHODS: Rats were exposed to acrolein (3.0 ppm, 6h/day, 7 days/week) and orally administered with rosiglitazone (2, 4, 8 mg/kg) once daily for up to 2 weeks. The expressions of Muc5ac protein and mRNA, and infiltration of inflammatory cells and levels of inflammatory cytokines (interleukin (IL)-1beta, IL-8 and tumor necrosis factor (TNF)-alpha) in bronchoalveolar lavage fluid (BALF) were detected with real-time PCR, Western blot, cell counting and ELISA. In addition, the role of nuclear factor (NF)-kappaB pathway in this process was also explored. RESULTS: Acrolein exposure significantly induced goblet cell hyperplasia in bronchial epithelium and Muc5ac mRNA and protein expressions in rat lungs, as well as the associated airway inflammation evidenced by the increased numbers of inflammatory cells and levels of inflammatory cytokines in BALF, which were attenuated with rosiglitazone treatment in a dose-dependent manner (P<0.05). Simultaneously, the increased expression of NF-kappaB and decreased expression of cytoplasmic IkappaB in acrolein-exposed lungs were reversed by rosiglitazone treatment. CONCLUSIONS: These findings suggest that PPAR-gamma activation by its ligands can attenuate acrolein-induced airway mucus hypersecretion in rats, which may be involved in inhibition of NF-kappaB pathway.

VEGFR-2 antagonist SU5416 attenuates bleomycin-induced pulmonary fibrosis in mice.

OBJECTIVE: Abnormal angiogenesis is a central hallmark for the development and progression of idiopathic pulmonary fibrosis. It has been shown that vascular endothelial growth factor (VEGF) is one of the critical angiogenic factors in angiogenesis. The aim of the present study was to assess whether disruption of VEGF pathway would attenuate bleomycin-induced pulmonary fibrosis. METHODS: Bleomycin-induced pulmonary fibrosis mice were treated intraperitoneally with VEGF receptor tyrosine kinase inhibitor SU5416 at different phases after bleomycin infusion. We measured angiogenesis and inflammatory response in both bleomycin-treated and control mice, and correlated these levels with pulmonary fibrosis. RESULTS: The increased expressions of VEGF/VEGFR (Flk-1) were correlated to a larger number of microvessels and a higher score of pulmonary fibrosis. Early administration of SU5416 inhibited pulmonary collagen deposition, histopathologic fibroplasias and the activation of TGF-beta1/Smad3 signaling pathway in bleomycin-stimulated lung. These were also paralleled by a reduction of VEGF/VEGFR-2 (Flk-1) expression and microvessel numbers in lung. Furthermore, SU5416 inhibited inflammatory cell numbers and LDH activity in BALF and IL-13 expression in lung tissue at early inflammatory phase of bleomycin-induced pulmonary fibrosis. CONCLUSION: These results suggest that the VEGFR-2 inhibitor, SU5416, attenuates histopathologic fibroplasias and collagen deposition by regulating angiogenesis and inflammation in the lung.

Toll-like receptor 4 relates to lipopolysaccharide-induced mucus hypersecretion in rat airway.

BACKGROUND: Toll-like receptor 4 (TLR4) is a transmembrane protein that participates in the recognition of lipopolysaccharide (LPS), a potentially important source of inflammation. To investigate the role of TLR4 in LPS-induced airway mucus hypersecretion (AMH), we used a LPS-induced rat model treated with dexamethasone (DEX). METHODS: Rats were randomly divided into four experimental groups: 1) saline (SA)-treated with distilled water (DW) (control group); 2) LPS-treated with DW (LPS group); 3) LPS-treated with DEX (LPS plus DEX group); 4) SA-treated with DEX (DEX group). DEX (5 mg/kg) was intraperitoneally injected 1 h before being administered intratracheally with LPS. Expressions of TLR4 and MUC5AC were evaluated with RT-PCR, in situ hybridization, immunohistochemistry and Alcian blue/Periodic acid-schiff (AB/PAS) staining. RESULTS: Increased expressions of TLR4 protein and mRNA were found in rat airway treated with LPS and peaked on day 2 after LPS administration. Following this, LPS increased MUC5AC expression and AB/PAS-stained goblet cells in rat airway. Correlation analysis showed TLR4 correlated well with the expression of MUC5AC (r = 0.684, p <0.01) and AB/PAS-stained area (r = 0.781, p <0.01). In addition, DEX pretreatment significantly reduced LPS-induced overexpression of TLR4 (p <0.05) in rat airway. CONCLUSIONS: These results suggest TLR4 relates to LPS-induced AMH and support a role of TLR4 in DEX inhibition of LPS-induced AMH.

Macrolides attenuate mucus hypersecretion in rat airways through inactivation of NF-kappaB.

BACKGROUND AND OBJECTIVE: To examine the effect of a 14-membered ring macrolide on airway mucus hypersecretion in rats treated with LPS. METHODS: Mucus hypersecretion in rat airways was induced by intratracheal instillation of LPS. Rats treated with or without LPS were administered roxithromycin (1-10 mg/kg), josamycin (10 mg/kg) or amoxicillin (40 mg/kg), orally for 4 days. Expression of Muc5ac, nuclear factor (NF)-kappaB, and the mitogen-activated protein (MAP) kinases p38 and ERK1/2 in bronchial epithelium were detected by RT-PCR, immunohistochemistry or western blotting. Mucins, IL-1beta, IL-8 and tumour necrosis factor (TNF)-alpha in BAL fluid were assayed by enzyme-linked lectin assay and ELISA. RESULTS: LPS significantly induced the expression of Muc5ac mRNA and protein in bronchial epithelium, increased the release of mucins, IL-1beta, IL-8 and TNF-alpha, and increased neutrophil numbers in BAL. Moreover, LPS increased staining for NF-kappaB in the cytoplasm as well as nuclear translocation of NF-kappaB in airway epithelial cells. Upregulated expression of Muc5ac mRNA correlated positively with NF-kappaB activation and the levels of cytokines (P < 0.05). Roxithromycin (5 and 10 mg/kg) significantly attenuated bronchial Muc5ac expression and NF-kappaB nuclear translocation stimulated by LPS, and reduced neutrophil numbers, mucins and inflammatory cytokines in BAL (P < 0.05). However, LPS-stimulated expression of p38 and ERK1/2 in airway epithelium was not affected by roxithromycin. Josamycin and amoxicillin had no effects on Muc5ac expression, NF-kappaB activation or cytokine release. CONCLUSIONS: Roxithromycin inhibits the pulmonary inflammatory response and airway mucus hypersecretion induced by LPS. The inhibitory effect of roxithromycin on airway mucus hypersecretion may be mediated through reduction of NF-kappaB activation, neutrophil infiltration and release of inflammatory cytokines in the lung.