Transcriptomics reveals apigenin alleviates airway inflammation and epithelial cell apoptosis in allergic asthma via MAPK pathway.

Persistent chronic inflammation of the lungs and airway remodeling are important pathological features that cannot be ignored in patients with chronic asthma. Apigenin (API) is a natural small molecule compound with good anti-inflammatory and antioxidant activity that has been widely reported in recent years, but its role in chronic asthma is not well defined. Our study began with oral gavage intervention using API (10, 20 mg/kg) or dexamethasone (DEX, 2 mg/kg) in a BALB/c mouse model of ovalbumin (OVA) sensitization. Different doses of API intervention effectively reduced airway resistance in the administered group. Additionally, inflammation was downregulated, mucus secretion was reduced, and airway remodeling was inhibited in the API intervention group compared with the model group. Asthma-related inflammatory cytokines, such as IgE, IL-4, IL-5, IL-13, and IL-17, were downregulated in alveolar lavage fluid. Moreover, the apoptosis level of the administered group was found to be lower than that of the model group in the Tunel staining experiment. By analyzing transcriptome sequencing results, we found that API may exert anti-inflammatory and anti-apoptotic effects by inhibiting the MAPK pathway. Our subsequent results supported this conclusion, showing that the phosphorylation levels of ERKs, JNKs, and p38 MAPKs were inhibited in the administered group relative to the model group. Downstream expression of the apoptosis-related protein B-cell lymphoma-2 (Bcl-2) was upregulated, and the expression of Bcl-2-associated × protein (Bax) and cleaved caspase-3 was downregulated. To further investigate the specific mechanism by which API acted, we established an in vitro model with house dust mite (HDM) stimulation, using API (10, 20 µM) for administration intervention. The results showed that API was able to improve cell viability, inhibit ROS production, and reverse HDM-induced decreases in mitochondrial membrane potential (MMP) and apoptosis in airway epithelial cells via the MAPK pathway.

Iristectorigenin A exerts novel protective properties against airway inflammation and mucus hypersecretion in OVA-induced asthmatic mice: Iristectorigenin A ameliorates asthma phenotype.

BACKGROUND: Despite the substantial amount of efforts made to reduce morbidity and improve respiratory management, asthma control remained a major challenge for severe patients. Plant isoflavones, one of the most estrogenic compounds, are considered a potential alternative therapy for asthma. Iristectorigenin A, a naturally occurring isoflavone, is extracted from a variety of medical plants and its biological activity has not been reported previously. PURPOSE: In present study, we aim to reveal the potential therapeutic role of Iristectorigenin A against acute asthmatic mice. STUDY DESIGN: We established ovalbumin (OVA) induced asthmatic murine model and orally administrated Iristectorigenin A at concentration of 5 and 10 mg/kg and dexamethasone as a positive control substance. METHODS: Asthmatic murine model was established with OVA sensitization and challenge. Lung function was assessed with FinePoint Ventilation system recording lung resistance (RI) and lung compliance (Cydn). White cells were sorted and counted in BALF. Histopathological assessment was conducted by H&E, PAS, and Masson's trichrome staining on paraffin embedded lung tissues. BALF content of IL-4, IL-5, IL-33, IL-13, INF-γ, IL-9 and serum IgE, IgG1 were measured using ELISA kit. Expression levels of mRNAs associated with inflammatory cytokines and goblet cell metaplasia were evaluated via quantitative RT-PCR. Protein expression levels of FOXA3, MUC5AC, SPDEF were estimated by immunohistochemistry on lung tissue, while NOTCH1 and NOTCH2 expressions were evaluated by western blotting analysis. RESULTS: Iristectorigenin A resulted in improved airway hyperresponsiveness (AHR) mirrored by decreased RI and increased Cydn. With Iristectorigenin A, we also observed reduced number of BALF leukocytes, improved inflammatory cell infiltration in lung tissue, decreased content of BALF IL-4, IL-5, IL-33, but not IL-13, INF-γ, IL-9, and their mRNA levels, along with decreased levels of OVA-specific IgE, IgG1 in asthmatic mice. Additionally, Iristectorigenin A exhibited significant therapeutic potential on attenuating mucus production reflected by mitigated FOXA3 and MUC5AC immunostaining on the airway epithelium, as well as decreased mRNAs associated with goblet cell metaplasia. At last, a decrease in elevated expression level of NOTCH2, but not NOTCH1, in asthmatic mice lung tissue was observed by western blotting analysis. CONCLUSION: Our study provides strong evidence that Iristectorigenin A can be potential therapeutic agent ameliorating airway inflammation and mucus hypersecretion in allergic asthma. This is a first research reported the potential of Iristectorigenin A as an alternative therapeutic agent.

Efficacy and safety of modified Bushen Yiqi formulas (MBYF) as an add-on to formoterol and budesonide in the management of COPD: study protocol for a multicentre, double-blind, placebo-controlled, parallel-group, randomized clinical trial: FB-MBYF Trial.

BACKGROUND: Inhaled glucocorticoid corticosteroid (ICS), long-acting ß2-adrenoceptor agonist (LABA), and other drugs have limited therapeutic effects on COPD with significant individual differences. Traditional Chinese medicine (TCM)-modified Bushen Yiqi formula (MBYF) demonstrates advantages in COPD management in China. This study aims to evaluate the efficacy and safety of MBYF as an add-on to budesonide/formoterol in COPD patients and confirm the related genes affecting the therapeutic effect in the treatment of COPD. METHODS: In this multicentre, randomised, double-blind, placebo-controlled, parallel-group study, eligible patients with COPD will randomly receive a 360-day placebo or MBYF as an adjuvant to budesonide/formoterol in a 1:1 ratio and be followed up with every 2 months. The primary outcomes will be the frequency, times, and severity of acute exacerbation of COPD (AECOPD), COPD assessment test (CAT) score, and pulmonary function tests (PFTs). The secondary outcomes will include the modified Medical Research Council (mMRC) dyspnoea scale, 6-min walking test (6MWT), BODE index, quantitative scores of syndromes classified in TCM, inflammation indices, and hypothalamic-pituitary-adrenaline (HPA) axis function. We will also test the genotype to determine the relationship between drugs and efficacy. All the data will be recorded in case report forms (CRFs) and analysed by SPSS V.20.0. DISCUSSION: A randomized clinical trial design to evaluate the efficacy and safety of MBYF in COPD is described. The results will provide evidence for the combination therapy of modern medicine and TCM medicine, and individual therapy for COPD. TRIAL REGISTRATION: ID:  ChiCTR1900026124 , Prospective registration.

Efficacy and safety of Jia Wei Bushen Yiqi formulas as an adjunct therapy to systemic glucocorticoids on acute exacerbation of COPD: study protocol for a randomized, double-blinded, multi-center, placebo-controlled clinical trial.

BACKGROUND: Systemic glucocorticoids are effective for the management of chronic obstructive pulmonary disease (COPD) exacerbation but have serious adverse effects. Traditional Chinese medicine (TCM) can bring additional benefits to these patients but has few adverse effects. The present study aims to evaluate the efficacy and safety of Jia Wei Bushen Yiqi (JWBY) formulas in patients who suffer from COPD exacerbations and to investigate whether the short-term (5-days) systemic glucocorticoid therapy is non-inferior to the long-term (9-day) regime. METHODS: In this multi-center, randomized, double-blinded trial, eligible inpatients with COPD exacerbation are randomly assigned to four groups (A, B, C, and D). Group A will receive placebo plus 5-day prednisone, group B will receive placebo plus 9-day prednisone, group C will receive JWBY formulas plus 5-day prednisone, and group D will receive JWBY formulas plus 9-day prednisone. The primary outcomes are the time interval to the patient's next exacerbation during a 180-day following up and the COPD assessment test (CAT) during treatment. Secondary outcomes include lung function, TCM syndrome assessment, laboratory tests, and safety. The changes of the hypothalamic pituitary adrenaline axis (HPA axis) and inflammatory cytokine will be measured as well. DISCUSSION: By demonstrating the advantages of utilizing TCM and an appropriate duration of systemic glucocorticoids, this effectiveness comparison trial will provide new references to physicians on how to improve the management of COPD exacerbation. The results of HPA axis and inflammation cytokine measurements will shed light on the molecular mechanisms and entail further mechanism studies. TRIAL REGISTRATION: www.chictr.org.cn ChiCTR1900023364. Registered on 24 May 2019.

Baicalin Exerts Anti-Airway Inflammation and Anti-Remodelling Effects in Severe Stage Rat Model of Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is a worldwide epidemic. Current approaches are disappointing due to limited improvement of the disease development. The present study established 36-week side stream cigarette smoke induced rat model of COPD with advanced stage feature and evaluted the effects of baicalin on the model. Fifty-four Sprague-Dawley rats were randomly divided into six groups including room air control, cigarette smoke exposure, baicalin (40 mg/kg, 80 mg/kg, and 160 mg/kg), and budesonide used as a positive control. Rats were exposed to cigarette smoke from 3R4F research cigarettes. Pulmonary function was evaluated and pathological changes were also observed. Cytokine level related to airway inflammation and remodelling in blood serum, bronchoalveolar lavage fluid, and lung tissue was determined. Blood gases and HPA axis function were also examined, and antioxidant levels were quantified. Results showed that, after treatment with baicalin, lung function was improved and histopathological changes were ameliorated. Baicalin also regulated proinflammatory and anti-inflammatory balance and also airway remodelling and anti-airway remodelling factors in blood serum, bronchoalveolar lavage fluid, and lung tissue. Antioxidant capacity was also increased after treatment with baicalin in COPD rat model. HPA axis function was improved in baicalin treated groups as compared to model group. Therefore, baicalin exerts lung function protection, proinflammatory and anti-inflammatory cytokine regulation, anti-airway remodelling, and antioxidant role in long term CS induced COPD model.

The Analysis of Constitutions of Traditional Chinese Medicine in Relation to Cerebral Infarction in a Chinese Sample.

OBJECTIVE: To investigate the relationships between the constitutions of Traditional Chinese Medicine (TCM) and patients with cerebral infarction (CI) in a Chinese sample. METHODS: A total of 3748 participants with complete data were available for data analysis. All study subjects underwent complete clinical baseline characteristics' evaluation, including a physical examination and response to a structured, nurse-assisted, self-administrated questionnaire. A population of 2010 neutral participants were used as the control group. Multiple variable regression (MLR) were employed to estimate the relationship between constitutions of TCM and the outcome. DESIGN: A cross-sectional study was conducted to evaluate the association of body constitution of TCM and CI. SETTINGS/LOCATION: Communications and healthcare centers in Shanghai. SUBJECTS: A total of 3748 participants with complete data were available for data analysis. OUTCOME MEASURES: All study subjects underwent complete clinical baseline characteristics' evaluation, including a physical examination and response to a structured, nurse-assisted, self-administrated questionnaire. A population of 2010 neutral participants were used as the control group. MLR were employed to estimate the relationship between constitutions of TCM and the outcome. RESULT: The prevalence of CI was 2.84% and 4.66% in neutral participants and yang-deficient participants (p = 0.012), respectively. Univariate analysis demonstrated a positive correlation between yang deficiency and CI. After adjustment for relevant potential confounding factors, the MLR detected significant associations between yang deficiency and CI (odds ratio = 1.44, p = 0.093). CONCLUSION: A yang-deficient constitution was significantly and independently associated with CI. A higher prevalence of CI was found in yang-deficient participants as compared with neutral participants.

A Study of Traditional Chinese Medicine Body Constitution Associated with Overweight, Obesity, and Underweight.

OBJECTIVE: The aim of the study was to investigate the associations among the nine types of body constitution in traditional Chinese medicine (TCM) with the outcomes of overweight, obesity, and underweight. METHOD: Participants aged 30 to 90 years were recruited from communities in Shanghai and assessed using a self-administered questionnaire pertaining to their demographics, lifestyles, and self-reported medical history. The data of 3748 participants with complete information was available for the analysis. Multinomial logistic regression (MLR) analysis was performed to determine the associations among the TCM constitution variables and the health outcomes. RESULTS: The standards of classification and determination of the constitution in TCM were used to gauge the patients' constitution type. MLR revealed independent and significant associations among the Qi_Deficient and Yang_Deficient groups with the outcomes of overweight, obesity, and underweight (P < 0.10 for all). MLR revealed independent and significant associations among the Qi_Deficient and Yang_Deficient groups with the outcomes of overweight, obesity, and underweight (P < 0.05 for all). CONCLUSION: Our study revealed significant negative correlations between the Qi_Deficient and Yang_Deficient groups with the outcomes of overweight, obesity, and underweight. On the other hand, positive correlations were found between Phlegm_Dampness and the outcomes of overweight and obesity.

Regulation of hypothalamic-pituitary-adrenal axis activity and immunologic function contributed to the anti-inflammatory effect of acupuncture in the OVA-induced murine asthma model.

Asthma is a complex inflammatory disease of the airways and acupuncture is one of the effective therapies widely used to treat asthma in China. The aim of the study was to evaluate the regulatory role of acupuncture in airway inflammation and the hypothalamic-pituitary-adrenal (HPA) axis activity in OVA-induced murine asthma model. Our results demonstrated that acupuncture was effective in suppression of AHR, inhibition of total leukocyte, neutrophil, lymphocyte and eosinophil counts in BALF, attenuation of airway inflammation and TNF-α, IL-1ß, IL-5 and eotaxin secretion. Furthermore, the HPA axis activity was also regulated by acupuncture, which included promotion of adrenocorticotropic hormone and cortisol secretion in the plasma. Our findings revealed that acupuncture could attenuate airway inflammation and regulate HPA axis and immunologic function in the OVA-induced murine asthma model, which may provide support to better understand the contribution of acupuncture to the regulation of airway inflammation and HPA axis activity in asthma.

Acupuncture Attenuated Inflammation and Inhibited Th17 and Treg Activity in Experimental Asthma.

Acupuncture is an effective therapeutic method in asthma treatment in traditional Chinese medicine. Here, we evaluated the effect of acupuncture on airway hyperresponsiveness (AHR) and the associated inflammatory changes as well as Th17 and Treg activity in ovalbumin- (OVA-) induced experimental asthma. Our results revealed that acupuncture treatment significantly inhibited AHR, lung inflammation, and mucus secretion of experimental asthma mice. Furthermore, a decrease in lymphocytes and eosinophils as well as neutrophils was observed in bronchoalveolar lavage fluid (BALF) of mice treated with acupuncture. Acupuncture reduced the OVA specific IgE level as well as the Th17 cytokine levels including IL-17A, IL-17F, and IL-22 in the serum of the experimental asthma mice. Acupuncture treatment group also had reduced CD4+IL-17A+ cell numbers and increased CD4+Foxp3+ cell numbers in BALF. In addition, acupuncture could inhibit IL-17R, RORγt, p65, and the inhibitor of NF-κB kinase-α (IKKα) protein expression. Our results indicated that acupuncture was effective in inhibiting AHR and inflammation in OVA-induced experimental asthma, which may be associated with the regulation of Th17 and Treg activity and NF-κB pathway.

Effects of two Chinese herbal formulae for the treatment of moderate to severe stable chronic obstructive pulmonary disease: a multicenter, double-blind, randomized controlled trial.

OBJECTIVE: The study aims to evaluate the efficacy and safety of two Chinese herbal formulae for the treatment of stable COPD. METHODS: A multicenter, double-blind, double-dummy, and randomized controlled trial (RCT) was conducted. All groups were treated with additional conventional medicines. There were a 6-month treatment and a 12-month follow-up for 5 times. Primary outcomes included lung function test, exacerbation frequency, score of SGRQ. Second outcomes consisted of 6MWD, BODE index, psychological field score, inflammatory factors and cortisol. RESULTS: A total of 331 patients were randomly divided into two active treatment groups (Bushen Yiqi (BY) granule group, n = 109; Bushen Fangchuan (BF) tablet group, n = 109) and a placebo group (n = 113). Finally 262 patients completed the study. BY granule & BF tablet increased the values of VC, FEV1 (%) and FEV1/FVC (%), compared with placebo. BY granule improved PEF. Both treatments reduced acute exacerbation frequency (P = 0.067), BODE index and psychological field score, while improved 6MWD. In terms of descent rang of SGRQ score, both treatments increased (P = 0.01). Both treatments decreased inflammatory cytokines, such as IL-8, and IL-17(P = 0.0219). BY granule obviously descended IL-17(P<0.05), IL-1ß (P = 0.05), IL-6, compared with placebo. They improved the level of IL-10 and cortisol. BY granule raised cortisol (P = 0.07) and decreased TNF-α. Both treatments slightly descended TGF-ß1. In terms of safety, subject compliance and drug combination, there were no differences (P>0.05) among three groups. CONCLUSIONS: BY granule and BF tablet were positively effective for the treatment of COPD, and the former performed better in general. TRIAL REGISTRATION: Chinese Clinical Trial Register center ChiCTR-TRC-09000530.

Effects of Psoraleae fructus and its major component psoralen on Th2 response in allergic asthma.

This study is aimed to evaluate the effects of Psoraleae fructus (PF) on Th2 responses in a rat model of asthma in vivo and psoralen, a major constituent in PF, on Th2 responses in vitro. A rat model of asthma was established by sensitization and challenged with ovalbumin (OVA). Airway hyperresponsiveness was detected by direct airway resistance analysis. Lung tissues were examined for cell infiltration and mucus hypersecretion. Bronchoalveolar lavage fluid (BALF) was assessed for cytokine levels. In vitro study, Th2 cytokine production was evaluated in the culture supernatant of D10.G4.1 (D10 cells) followed by the determination of cell viability, meanwhile Th2 transcription factor GATA-3 expression in D10 cells was also determined. The oral administration of PF significantly reduced airway hyperresponsiveness (AHR) to aerosolized methacholine and decreased IL-4 and IL-13 levels in the BALF. Histological studies showed that PF markedly inhibited inflammatory infiltration and mucus secretion in the lung tissues. In vitro study, psoralen significantly suppressed Th2 cytokines of IL-4, IL-5 and IL-13 by ConA-stimulated D10 cells without inhibitory effect on cell viability. Furthermore, GATA-3 protein expression was also markedly reduced by psoralen. This study demonstrated that PF exhibited inhibitory effects on hyperresponsiveness and airway inflammation in a rat model of asthma, which was associated with the suppression of Th2 response. Psoralen, a major constituent of PF, has immunomodulatory properties on Th2 response in vitro, which indicated that psoralen might be a critical component of PF for its therapeutic effects.

Flavonoid components in Scutellaria baicalensis inhibit nicotine-induced proliferation, metastasis and lung cancer-associated inflammation in vitro.

The objective of the present study was to investigate the therapeutic efficacy of flavonoid components in Scutellaria baicalensis on proliferation, metastasis and lung cancer-associated inflammation during nicotine induction in the A549 and H1299 lung cancer cell lines. After experimental period, augmentation of proliferation was observed, accompanied by marked decrease in apoptotic cells in nicotine-induced lung cancer cells; additionally, nicotine-exposed cells exhibited increased invasive and migratory abilities based on invasion and wound-healing assay. Flavones in Scutellaria, baicalin, baicalein and wogonin significantly counteracted the above deleterious changes. Moreover, assessment of tumor apoptotic and metastatic factors on mRNA levels by quantitative PCR and protein levels by western blotting revealed that these phytochemical treatments effectively negated nicotine-induced upregulated expression of bcl-2, bcl-2/bax ratio, caspase-3, matrix metalloproteinase (MMP)-2 and MMP-9 as well as downregulated expression of bax. Further analysis of inflammatory markers such as tumor necrosis factor (TNF)-α and interleukin (IL)-6 in cell culture supernatant and mRNA and protein expression of nuclear transcription factor-kappaB (NF-κB) and I kappa B-alpha (IκB-α) was carried out to substantiate the anti-inflammatory effect of flavones in Scutellaria in nicotine-exposed lung cancer cells. The therapeutic effects observed in the present study are attributed to the potent potential against proliferation, metastasis and inflammatory microenvironment by flavonoid components in Scutellaria in nicotine-induced lung cancer cells.

Establishment and comparison of combining disease and syndrome model of asthma with "kidney yang deficiency" and "abnormal savda".

THE STUDY WAS THE FIRST TIME TO ESTABLISH AND COMPARE TWO RAT MODELS OF TWO COMMON SYNDROMES: Kidney Yang Deficiency syndrome (KYDS) in traditional Chinese medicine (TCM) and abnormal savda syndrome (ASS) in traditional Uighur medicine (TUM). Then, we also established and evaluated rat models of combining disease and syndrome models of asthma with KYDS or ASS. Results showed that usage of the high dose of corticosterone (CORT) injection or external factors could successfully establish the KYDS or ASS rat models, and the two models had similar changes in biological characterization, abnormal behaviors, dysfunction of hypothalamic-pituitary-target organ axes (HPTOA), and sympathetic/parasympathetic (S/P) nerve system but varied in different degrees. The rat models of combining disease and syndrome of asthma with KYDS or ASS had either pathological characteristics of asthma such as airway hyperresponsiveness (AHR), airway inflammation, airway remodeling, which were more serious than allergy exposure alone, or the syndrome performance of Kidney Yang Deficiency in TCM and abnormal savda in TUM. These findings provide a biological rationale for further investigation of combining disease and syndrome model of asthma as an effective animal model for exploring asthma based on the theory of traditional medicine.

Effects of baicalin on airway remodeling in asthmatic mice.

Airway remodeling is an important characteristic of asthma, linking inflammation with airway hyperresponsiveness. Baicalin, a major active component, was isolated from Radix Scutellariae. Many studies show that baicalin has anti-inflammatory, anti-bacterial, and anti-allergic effects. Here we investigate the influence of baicalin on asthmatic airway remodeling and the mechanism underlining the anti-remodeling effect in vivo.Asthmatic airway remodeling mice model was established by ovalbumin exposure. Seventy female BALB/c mice were randomly assigned to seven experimental groups: blank, ovalbumin, hexadecadrol, control, and baicalin (25 mg/kg, 50 mg/kg, 100 mg/kg) groups. Pulmonary function was measured using a whole-body plethysmograph in conscious and unrestrained mice. The lung pathology was observed and measured. The production of cytokines in bronchoalveolar lavage fluid and serum was measured using enzyme-labeled immunosorbent assay kits, and the expression levels of transforming growth factor-ß1 and vascular endothelial growth factor were detected by immunohistochemistry. The protein expression levels of transforming growth factor-ß1, vascular endothelial growth factor, extracellular signal-regulated kinase, and p21ras were measured using Western blot. The results show that ovalbumin exposure significantly increased the expression of interleukin-13 in BALF and serum, and transforming growth factor-ß1, vascular endothelial growth factor, extracellular signal-regulated kinase and p21ras expressions in the lungs. Baicalin attenuated the effects of ovalbumin significantly.It can be concluded that baicalin has significant anti-remodeling effect on ovalbumin-induced asthmatic airway remodeling mice model by decreasing expression of transforming growth factor-ß1, interleukin-13, and vascular endothelial growth factor and inhibiting the activation of the extracellular signal-regulated kinase pathway.

CD4+CD25+Foxp3+ T cells contribute to the antiasthmatic effects of Astragalus membranaceus extract in a rat model of asthma.

Astragalus membranaceus (AM), a traditional Chinese medicinal herb, has been widely used for centuries to treat asthma in China. Previous studies demonstrated that AM had inhibitory effects on airway hyperresponsiveness, inflammation and airway remodeling in murine models of asthma. However, it remained unclear whether the beneficial effects of AM on asthma were associated with CD4(+)CD25(+)Foxp3(+) Treg cells; this issue is the focus of the present work. An asthma model was established in Sprague-Dawley (SD) rats that were sensitized and challenged with ovalbumin. Bronchoalveolar lavage fluid (BALF) was assessed for inflammatory cell counts and cytokine levels. Airway hyperresponsiveness was detected by direct airway resistance analysis. Lung tissues were examined for cell infiltration, mucus hypersecretion and airway remodeling. CD4(+)CD25(+)Foxp3(+) Treg cells in the BALF and Foxp3 mRNA expression in lung tissues were examined. The oral administration of AM significantly reduced airway hyperresponsiveness to aerosolized methacholine and inhibited eosinophil counts and reduced IL-4, IL-5 and IL-13 levels and increased INF-γ levels in the BALF. Histological studies showed that AM markedly decreased inflammatory infiltration, mucus secretion and collagen deposition in the lung tissues. Notably, AM significantly increased population of CD4(+)CD25(+)Foxp3(+) Treg cells and promoted Foxp3(+) mRNA expression in a rat model of asthma. Together, these results suggest that the antiasthmatic effects of AM are at least partially associated with CD4(+)CD25(+)Foxp3(+) Tregs.

Baicalin is anti-inflammatory in cigarette smoke-induced inflammatory models in vivo and in vitro: A possible role for HDAC2 activity.

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease characterized by airway obstruction and progressive lung inflammation, which is insensitive to corticosteroids therapies. In this study, we investigated the mechanism underlying the attenuation of cigarette smoke (CS)-induced respiratory inflammation by baicalin, a flavonoid compound isolated from the root of Scutellaria baicalensis Georgi, in vivo and in vitro. In vivo, mice were exposed to smoke of 15 cigarettes for 1 h/day, 6 days/week for 3 months and dosed with baicalin (25, 50 and 100mg/kg) or dexamethasone (1mg/kg). In vitro, A549 cells were incubated with baicalin (10, 50 and 100 µM) or dexamethasone (10(-12), 10(-10), 10(-8) and 10(-6)M) followed by treatments with cigarette smoke extract (CSE, 2.5 and 5%), or TNF-α (10 ng/ml), or trichostatin A (TSA, 100 ng/ml). We found that baicalin significantly protected pulmonary function and attenuated CS-induced inflammatory response by decreasing inflammatory cells and production of TNF-α, IL-8 and MMP-9. This result was not found in the group treated with dexamethasone. Baicalin also showed efficacy in enhancing histone deacetylase (HDAC)2 activity and protein expression, however, it did not affect HDAC2 mRNA. Further studies revealed that baicalin inhibited HDAC2 phosphorylation, suggesting that it may directly affect the protein structure and effect by modification at post-translational level. Together these results suggest that baicalin has anti-inflammatory effects in cigarette smoke induced inflammatory models in mice and A549 cells, possibly achieved by modulating HDAC2.