Effect of hydrogen sulfide on airway inflammation induced by ozone in mice

AIM: To investigate the effect of hydrogen sulfide (H₂S) on airway inflammation induced by ozone (O₃) exposure and its mechanisms.METHODS: C57BL/6 mice (n=32) were randomly divided into control group, O₃ group, NaHS+O₃ group and NaHS group. The mice in O₃ group and O₃+NaHS group were exposed to 2.14 mg/m³ O₃ for 3 h on days 1, 3 and 5, while the mice in control group and NaHS group were exposed to filtered air. NaHS (14 μmol/kg) was administered intraperitoneally to the mice in NaHS group and O₃+NaHS group 30 min before each exposure. After the last exposure for 24 h, the airway responsiveness was determined, and bronchoalveolar lavage fluid (BALF) was collected for counting inflammatory cells and measuring total protein concentration. The lung tissues were collected for observing the morphological changes with HE staining. The levels of interleukin-6 (IL-6), interleukin-8 (IL-8), malondialdehyde (MDA) and NF-κB p65 protein in the lungs were determined.RESULTS: Compared with control group, the airway responsiveness, inflammatory cells, protein concentration, inflammation score, levels of IL-6, IL-8, MDA and NF-κB p65 in O₃ group increased significantly, but these in NaHS+O₃ group decreased compared with O₃  group.CONCLUSION: The present findings suggest that H₂S attenuates O₃ induced airway inflammation by inhibiting NF-κB expression and preventing lipid peroxidation.     

Effect of intranasal treatment with Toll-like receptor 9 ligand CpG oligodeoxynucleotides on airway inflammation in mice with allergic combined airway disease

AIM: To investigate the therapeutic effect of intranasal administration of CpG oligodeoxynucleotides (CpG-ODN), compared with intradermal administration, on lower airway inflammation in ovalbumin (OVA)-induced allergic combined airway disease (ACAD) mouse model.METHODS: Totally 30 female BALB/c mice aged from 6 to 8 weeks were randomly divided into control group, allergic rhinitis model group (AR group), ACAD group, ACAD intranasally treated with CpG-ODN group (CpG i.n. group) and ACAD intradermally treated with CpG-ODN group (CpG i.d. group). The mice were sensitized and challenged with OVA. Treatment with CpG-ODN was also performed during challenge, either intranasally or intradermally. Immunologic variables and nasal symptom were studied.RESULTS: Compared with CpG i.d. group and ACAD group, the percentage of eosinophils from bronchoalveolar lavage fluid (BALF), the levels of Th2 cytokine production in BALF and supernatants of cultured splenic lymphocytes, OVA-specific IgE from blood, peribronchial inflammation score in the lung, and nasal symptoms were significantly reduced in CpG i.n. group.CONCLUSION: Allergic rhinitis treated by CpG-ODN has a significant improvement on lower airway inflammation in ACAD mouse model; and it may be more effective when administrated intranasally than intradermally.     

Effect of erythromycin on transforming growth factor-β1 and γ-glutamylcysteine synthetase in lung of smoking rats

AIM: To investigate the effect of erythromycin on the level of transforming growth factor-β₁ (TGF-β₁) and γ-glutaglutamylcysteine synthetase (γ-GCS) in smoking rats,and to explore the antioxidate therapeutic role of erythromycin in chronic obstructive pulmonary disease.METHODS: Wistar rats were exposed to cigarettes smoking to establish the model.After passive smoking for 4 weeks,erythromycin intragastric intervention was administered continuously for 8 weeks.The expiratory airway resistance and lung compliance were assessed and the expression levels of TGF-β₁ and γ-GCS proteins (and the mRNA) in airway endothelial cells and alveolar macrophages were observed respectively by immunohistochemical,immunocytochemical and (in situ) hybridization.RESULTS: The expiratory airway resistance was increased and the lung compliance was degraded significantly in smoking group and erythromycin group,compared to control group.In erythromycin group,the airway resistance was lower and the lung compliance was higher than that in smoking group (P<0.05).The levels of TGF-β₁ and γ-GCS in smoking group and erythromycin group was obviously increased in airway endothelial cells and alveolar macrophages in comparison with control group (P<0.05).The levels of TGF-β₁ and γ-GCS were inhibited by erythromycin (P<0.05).TGF-β₁ was obviously positive correlated with γ-GCS in smoking group,but this was not found in erythromycin group.CONCLUSION: Erythromycin therapy improves pulmonary function and relieves emphysema change induced by smoking in rats,and decreases the expression of TGF-β₁ and γ-GCS in alveolar macrophages and airway endothelial cells,suggesting that erythromycin may play a role in the antioxidate therapeutic in COPD.     

Effect of azithromycin on airway inflammation and airway mucus hypersecretion in rats with chronic obstructive pulmonary disease

AIM: To observe the effect of azithromycin on the rats with chronic obstructive pulmonary disease (COPD), and to explore the underlying mechanism about the airway inflammation and mucus hypersecretion. METHODS: Male SD rats were randomly divided into normal control group, COPD model group, azithromycin treatment group. The COPD model was established by the method of cigarette smoking combined with intratracheal injection of LPS. Pathological changes of the bronchi and lung tissues of the rats were observed with HE staining. Pulmonary ventilation function in the rats was detected with pulmonary function instrument. The levels of IL-8, IL-17 and TNF-α in bronchoalveolar lavage fluid (BALF) were measured by ELISA. The expression of MUC5ac and TLR4 at mRNA and protein levels in bronchi and lung tissues was determined by real-time PCR and Western blot.RESULTS: HE staining showed that the changes of bronchi and lung tissues in model group were consistent with typical pathological manifestations of COPD. Compared with model group, these changes were alleviated in treatment group. The pulmonary functions in model group were significantly decreased compared with control group. The levels of IL-8, IL-17 and TNF-α in the BALF in model group were significantly increased compared with control group (P <0.05). The expression of MUC5ac and TLR4 at mRNA and protein levels in model group was significantly higher than that in control group (P <0.05). Compared with model group, the degree of the descent in pulmonary function in treatment group was significantly lessened. Compared with model group, the levels of IL-8, IL-17 and TNF-α in treatment group were significantly inhibited (P <0.05). Furthermore, the expression of MUC5ac and TLR4 at mRNA and protein levels in treatment group was significantly lower than that in model group (P <0.05). CONCLUSION: Azithromycin decreases the levels of IL-8, IL-17 and TNF-α in the BALF of COPD model rats, inhibits the protein expression of MUC5ac and TLR4 in the lung tissues, thus playing a preventive and therapeutic role to reduce airway inflammation and airway mucus hypersecretion.     

Establishment of chronic obstructive pulmonary disease rat models by passive cigarette smoking and intratracheal instillation of lipopolysaccharide

AIM:To establish rat chronic obstructive pulmonary disease(COPD) models by passive cigarette smoking plus intratracheal instillation of lipopolysacchride(LPS) or passive cigarette smoking only, which would be similar to the pathogenesis of human COPD. METHODS:48 Wistar rats were randomly divided into 4 groups.(1) Healthy control I group(n=12), rats were bred 4 weeks;healthy control II group(n=12), rats were bred for 3months. (2) Model group I (n=12), 200μg lipopolysaccharide(LPS) was instilled intratracheally once for every two weeks and the rats were exposured to 5% of cigarette smoke, 0.5 h/d for 4 weeks.(3) Model group II(n=12),rats were exposed to 5% of cigarette smoke, 0.5 h/d for 3 months. The pathologic changes of airways and lung tissues, pulmonary function and blood gas analysis were determined. The airway wall lymphocytes and alveolar macrophages were counted. The cross areas of epithelial layer, smooth muscle layer and lamina propria of bronchi were measured. The hydroxyproline of lung tissue homogenates was determined by biochemistry method.RESULTS:The pathologic changes of airways and lung tissue of two models were similar to but milder than those of COPD patients(biopsy data). The collagen deposition and the cross areas of epithelial layer and smooth muscle layer in airway walls of two model groups were significantly increased than those of control groups(P＜0.01,P＜0.05).FEV_0.3/FVC% of two model groups, PaO₂ and SaO₂ of model I group were significantly decreased, while R_i and R_e in model I group were significantly increased than that of control I group(P＜0.05). The PaCO₂ and the counts of lymphocytes and alveolar macrophages of both model groups were significantly increased than those of the control groups (P＜0.01). Lots of alveolar macrophages had phagocyted smoke granules. The amounts of hydroxyproline of two model groups were significantly increased than those of control group((P＜0.05) and were negatively related to the FEV_0.3/FVC%, respectively (P＜0.01,P＜0.01) and positively related to airway resistance of model I group(P＜0.01). CONCLUSIONS:COPD rat models were successfully established by passive cigarette smoking plus intratracheal instillation of LPS and cigarette smoking only. The pathologic changes were similar but milder than those of COPD patients. The airway obstruction of model I group was more severe than that of model II group, but they have no significant difference.     

Inhibitory effect of T-bet gene transfer on airway inflammation in a established murine allergic asthmatic model

AIM: To investigate the effect of T-bet plasmid gene transfer to airway on allergen induced airway inflammation in a murine asthmatic model. METHODS: A mouse asthma model was established by sensitization with ovalbumin (OVA). Forty C57BL/6 mice were divided into 4 groups (10 mice in each group): the normal control group (group A), the asthmatic model group (group B), the pcDNA3 plasmid group (group C), and the pcDNA3-T-bet group (group D). The animals in group B, C and D were sensitized and challenged with OVA. The animals in group A were applied with normal saline. pcDNA3 plasmid at dose of 50 μg was intranasally administered at 24 h before intranasal challenges to the mice in group C, and the 50 μg pcDNA3-T-bet plasmid for the mice in group D. Bronchial alveolar lavage fluid (BALF) was collected and lung tissues were resected at 48 h after OVA challenge for later assay. RESULTS: After administration with pcDNA3-T-bet plasmid, high level of T-bet expression at 48 h was detected in the lung tissue by Western blotting. In pcDNA3-T-bet treated asthmatic models, histological evaluation revealed the significant suppression of eosinophil peribronchial and perivascular infiltration, and reduction of epithelial damage. The numbers of eosinophils, neutrophils and lymphocytes in BALF from pcDNA3-T-bet treated mice were significantly reduced compared to those in asthmatic control group (P<0.05). The level of IL-4 in BALF was significantly decreased in pcDNA3-T-bet group compared to that in asthmatic control group (P<0.05), while the level of IFN-γ in BALF was significantly increased in pcDNA3-T-bet group. No significant change of inflammation cells and cytokines in pcDNA3 plasmid group and asthmatic control group was observed (P>0.05). CONCLUSION: Intranasal pcDNA3-T-bet plasmid transfer inhibits asthmatic airway inflammation in the murine asthmatic model, suggesting a new therapeutic strategy for allergic asthma.     

Etanercept attenuates bleomycin-induced lung fibrosis in mice

AIM: To evaluate the effect of tumor necrosis factor α (TNF-α) antagonist etanercept on bleomycin-induced lung fibrosis in mice.METHODS: Forty-five Kunming female mice were randomly divided into 3 groups: the mice in control group were intraperitoneally injected with vehicle and intratracheally administered with saline aerosol, the mice in bleomycin group were intraperitoneally injected with vehicle and intratracheally administered with bleomycin (3 mg/kg) aerosol, and the mice in bleomycin+etanercept group were intraperitoneally injected with etanercept (4 mg/kg) every 3 d and intratracheally administered with bleomycin aerosol. All animals were sacrificed 28 d after treatments. The left lung was fixed in 10% neutral formalin and then stained with hematoxylin-eosin or Masson’s trichrome for the pathological examination. The tissues of right lung were sampled for measuring the content of hydroxyproline (HYP) by the method of alkaline hydrolysis. The serum concentrations of TNF-α and TGF-β were detected by ELISA. Total tissue protein was extracted for examination of ERK1/2, JNK and p38 by Western blotting.RESULTS: Etanercept prevented the collagen accumulation under the airway epithelium and decreased the scores of lung inflammation and fibrosis induced by bleomycin with significantly reduced the levels of tissue HYP, serum TNF-α and serum TGF-β. The protein phosphorylations of ERK/JNK/p38 in the lung tissues were remarkably decreased compared with BLM group.CONCLUSION: Etanercept decreases the phosphorylations of ERK1/2/JNK/p38 via inhibiting the expression of TNF-α and TGF-β. Etanercept might be useful in the treatment of pulmonary fibrosis.     

Improvement and evaluation of chronic bronchitis modeling methods in mice

AIM: To explore a more accurate and reliable pathological model of the chronic bronchitis, which has improved from the former single-factor modeling method of the disease.METHODS: The mice in complex group were treated with lipopolysaccharide(LPS) by tracheal injection on the 1st day and nasal drops on the 14th day, and from the 2nd day to 30th day, the animals were given passive smoking and sulfur dioxide(SO₂) inhalation(except on the 14th day). The mice in SO₂ group were exposed to SO₂ 2 min per day, while in smoking group, the mice were exposed to smoke for about 1 h per day(4 cigarettes each time until one pack of cigarettes were burning up). In LPS group, the mice had tracheal injection of LPS on the 1st day and nasal drops of LPS on the 14th day and 30th day. Every modeling process lasted for 30 days. After modeling, the improvement of chronic bronchitis model was evaluated by testing the general conditions of the mice, analyzing leukocyte count in bronchoalveolar lavage fluid(BALF), and observing the morphological changes of the bronchial and lung tissues.RESULTS: After modeling, the mice in every model group experienced symptoms including wet nose, cough, dry and lusterless hair, arched back and curled-up body, showing inactive, and slow down in response. The mice in complex group gained the lowest weight compared to other groups. From each model group, the inflammatory cells infiltrated evidently around the bronchial walls, especially in the bronchial cavity, and the mucilage secretion in the airway increased. The total number of leukocytes in BALF increased significantly in complex group. The inflammatory cell count in the lung tissue indicated that the mice in complex group had significantly higher levels of inflammatory cell infiltration. Besides, the comparison between smoke group and LPS group was statistically significant.CONCLUSION: Smoking, SO₂ inhalation and LPS injection induce bronchial lung disease in mice, and the complex chronic bronchitis mouse model is a better model with the pathological changes of bronchus, lung tissue and BALF, and pathogenesis of chronic bronchitis.     

Effect of Kechuanning on airway remodeling and protein level of p-ERK1/2 in lung tissues of asthmatic rats induced by virus

AIM:To investigate the effect of Kechuanning on airway remodeling and the protein level of p-ERK1/2 in lung tissues of asthmatic rats induced by virus. METHODS:The asthmatic rat model induced by respiratory syncytial virus was established. The experimental rats were divided into normal group, asthma model group, low dose (0.33 mL/kg), middle dose (3.0 mL/kg) and high dose (10 mL/kg) of Kechuanning groups, and PD98059 (3 mg/kg) group. The airway responsiveness of the rats was measured by animal ventilator. The pathological changes of the lung tissues were observed by HE staining. PAS staining and Masson staining were used to observe goblet epithelial cells metaplasia and airway collagen deposition. The expression of matrix metalloproteinases-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in the lung tissues of the rats was detected by immunohistochemical staining. The protein levels of ERK1/2 and p-ERK1/2 were determined by Western blot. RESULTS:Compared with model group, the airway responsiveness of the rats in middle dose and high dose of Kechuanning groups was significantly decreased (P<0.01), the injury of lung tissues was significantly decreased, the goblet epithelial cells metaplasia and airway collagen deposition were significantly reduced (P<0.01), and the expression of MMP-9 and TIMP-1 in the lung tissues was also significantly decreased (P<0.01). In addition, the protein level of p-ERK1/2 in high dose of Kechuanning group was significantly decreased compared with model group (P<0.01). CONCLUSION:Kechuanning may treat asthma by regulating the expression of p-ERK1/2 in the lung tissues and improving the airway remodeling symptoms of asthmatic rats induced by virus.     

Protective effect of recombinant human serum albumin-thioredoxin fusion protein on mice with acute lung injury induced by influenza virus

AIM To investigate the protective effect of recombinant human serum albumin (HSA)-thioredox?in (Trx) fusion protein (HSA-Trx) on mice with acute lung injury (ALI) induced by influenza virus infection. METH?ODS: The recombinant HAS-Trx fusion protein was generated by Pichia pastoris expression system. ICR mice were used to establish the animal model of ALI induced by PR8 (H1N1) influenza virus, and the experimental mice were divided into healthy control group, ALI group, ALI+Trx group and ALI+HSA-Trx group, with 10 mice in each group. The bronchoalveolar lavage fluid (BALF) in each group was collected, the total number of cells and the number of alveolar neutrophils were determined, the protein concentration was measured by Coomassie brilliant blue solution method, and the interferon-γ (IFN-γ) content in BALF was detected by ELISA. The lung tissues were collected for hematoxylin and eosin staining. The inducible nitric oxide synthase (iNOS), 8-hydroxydeoxyguanosine (8-OHdG) and 3-nitrotyrosine (NO₂-Tyr) in lung tissues were detected by immunofluorescence method. Peroxide concentration in plasma was evaluated using a CR2000RC analyzer. RESULTS HSA-Trx treatment significantly reduced the total number of cells, neutrophils and total protein in BALF of ALI mice (P<0.05), and decreased the levels of 8-OHdG, NO₂-Tyr in lung tissue and peroxide in plasma (P<0.05). However, it has no significant inhibitory effect on iNOS and IFN-γ expression (P>0.05). CONCLUSION HSA-Trx inhibits inflammatory response and excessive production of nitric oxide in the lung, thus protecting influ?enza virus-induced ALI mice.     

Effects of eosinophils deletion on sPLA2-X in bronchial asthma model mice

AIM To investigate the association between soluble phospholipase A2-X（sPLA2-X） and eosinophils in bronchial asthma， and to provide new insight and strategies for the treatment of bronchial asthma. METHODS Female Babl/c mice （n=48） of SPF grade and 6~8 weeks old were divided into 4 groups （with 12 in each group： healthy control group，asthma control group， eosinophil deletion group， and asthma /eosinophil deletion isotype control group）. The mouse model of bronchial asthma was constructed. The mice in healthy control group were intraperitoneally injected with saline on days 0， 7， and 14. The mice in other groups were intraperitoneally injected with 50 μg OVA and 2 mg aluminum hydroxide gel（soluble in 200 μL saline.On the 21st d and 26 th d， eosinophil deletion antibody （anti-CCR3） and isotype control were intraperitoneally injected and intranasally respectively， and then the lungs function test was conducted within 48 h after the end of nebulization.Half of the mice in each group were subjected to whole lung lavage， the remaining half were used for lung tissue section with HE staining， the whole blood was used to measure serum IgE， the supernatant of broncho alveolar lavage fluid （BALF） was used to measure cytokines， and total number of cells in the bronchoalveolar lavage fluid was analyzed for cell classification and flow cytometry. RESULTS （1）Compared with asthma control group，the airway and alveolar inflammatory responses in asthma/eosinophil deletion group was significantly alleviated.（2） Compared with asthma control group， anti-CCR3 successfully deleted eosinophils， and the percentage of eosinophils in bronchoalveolar lavage fluid in asthma/eosinophil deletion group was significantly reduced （P<0.05）.（3） The airway hyperresponsiveness in asthma/eosinophil deletion group was significantly decreased as compared with asthma control group（P<0.05）.（4） The levels of sPLA2-X in the serum and BALF was significantly reduced in asthma/eosinophil deletion group as compared with asthma control group（P<0.05）.（5）Compared with asthma control group，the levels of IL-4， IL-5， and IL-13 in the BALF of the mice in asthma/eosinophil deletion group were significantly reduced， and the serum level of IgE was also decreased （P<0.05）. CONCLUSION Eosinophils in bronchial asthma are importantly associated with sPLA2-X.     

Acute lung injury in mice caused by SARS-CoV spike glycoprotein

AIM: To investigate the effect of spike protein of SARS-CoV on the pathological and immunological changes in the lungs of mice and to explore the mechanism of spike protein induced acute lung injury. METHODS: BALB/c mice were randomly divided into groups: control (PBS), spike protein and γ-interferon-inducible protein-10(IP-10).The agents were given either by intracheal instillation or tail venous injection. Clinical symptom and mortality were observed. Whole wet lungs were separated and weighed, then fixed in formalin, embedded in paraffin, section slices were stained with hematoxylin and eosin for pathological examination. Expression of IP-10 in the lung of mice was evaluated using immunofluorescence method. RESULTS: Mice received spike protein inhalation or injection appeared to be short of breath, and died. Increased lung wet weight, obvious alveolar destruction, mesenchyma infiltration with inflammatory cells, epithelial and vascular endothelial swelling and shedding were demonstrated in spike protein group. Similar lung injury was found in the IP-10 group. Spike protein induced the expression of IP-10 in the airway epithelium and vascular endothelium of the lung.CONCLUSION: (1) Spike protein of SARS-CoV administered by inhalation or injection causes acute lung injury in mice. (2) Spike protein of SARS-CoV induces the expression of IP-10 in the lung of mice. (3) IP-10 causes acute lung injury in mice.     

Chronic exposure to house dust mite induces airway remodeling related to Th1 inflammation in mice

AIM: To investigate the inflammatory characteristics in the airway of mice with chronic exposure to dust mite. METHODS: The α-SMA-Cre/R26R transgenic reporter mice were intranasally exposed to dust mite extract for 60 d (DME group), and then subjected to the measurement of lung resistance. The performance of bronchoalveolar lavage, pathological changes of the lung tissues and splenocytes isolation 24 h after the last challenge were observed. The protein extracts from the lungs were subjected to the detection of α-smooth muscle actin (α-SMA) by Western blotting. The supernatants of the lung homogenate were collected for testing the levels of interleukin-4 (IL-4) and interferon-γ (IFN-γ) with enzyme-linked immunosorbent assay. CD4⁺ T-cell subsets of the splenocytes were analyzed by flow cytometry.RESULTS: The mice chronically exposed to dust mite extract demonstrated severe airway hyperresponsiveness. The pulmonary pathological sections with HE staining manifested strong evidence of airway remodeling in DME group, corresponding to an enhanced X-gal staining that is related to α-SMA activation in the subepithelial basement membrane of bronchia. Total cell and lymphocyte counts were increased in the lungs of DME group compared to control group. No difference was found in eosinophil count of mice between DME and control groups. There was an elevated level of IFN-γ in the lungs of DME challenged mice coordinated with an increased proportion of IFN-γ-producing CD4⁺ T cells in the splenocytes.CONCLUSION: Chronic exposure to dust mite in the mice induces Th1-dominant inflammation with an airway hyperresponsiveness and the development of airway remodeling.     

Protective effect of N-acetylcysteine on mice with acute lung injury induced by H9N2 swine influenza virus

AIM: To investigate the effects of N-acetylcysteine (NAC) on acute lung injury induced by H9N2 swine influenza virus (SIV) in mice. METHODS: BALB/c mice were used to establish the animal model of acute lung injury by nasal inoculation of H9N2 SIV. The mice were divided into control group (without SIV infection), H9N2 SIV group (inoculation of H9N2 SIV) and NAC group (inoculation of H9N2 SIV plus pretreatment with NAC). The pulmonary edema was evaluated by determining the lung wet weight/dry weight (W/D) ratio. The pathological changes of the lung tissues were observed. The concontrations of TNF-α, IL-1β and IL-6 in bronchoalveolar lavage fluid (BALF) were measured.The virus titer, T-SOD activity, MPO activity and MDA content in the homogenate of the lung tissues were detected. RESULTS: Treatment with NAC decreased the morality of infected mice, and significantly prolonged the survival time of infected mice. The pathological changes of the lung tissues, the lung W/D ratio and the lung index were relieved when SIV infected the mice treated with NAC. Treatment with NAC significantly decreased the infiltration of inflammatory cells including macrophages, lymphocytes and neutrophils in the BALF. The levels of TNF-α, IL-6, IL-1β and MDA and the activity of MPO were also decreased. Treatment with NAC also significantly increased the T-SOD activity. CONCLUSION: The protective effect of NAC on the acute lung injury mouse model is related to suppression of the oxidative stress and inflammatory responses.     

Antioxidant effect of carnosine on H9N2 swine influenza virus-induced acute lung injury in mice

AIM:To investigate the antioxidant effect of carnosine on H9N2 swine influenza virus (H9N2-SIV)-induced acute lung injury (ALI). METHODS:One hundred and fifty SPF female BALB/c mice (6 to 8 weeks old) were randomly divided into control group, ALI group and carnosine intervention group with 50 each. The mice in control group were inoculated intranasally with normal allantoic fluid of chick embryos. The mice in ALI group were inoculated intranasally with allantoic fluid containing H9N2-SIV. The mice in carnosine group were treated with H9N2-SIV plus carnosine. On the 2nd, 4th, 6th, 8th and 14th days after treatment, 8 mice in each group were killed to observe the pathological changes of the lung. Meanwhile, the activity of superoxide dismutase (SOD) and myeloperoxidase (MPO), the content of malondialdehyde (MDA) and the wet weight/dry weight ratio (W/D) of the lung tissues were determined. RESULTS:Carnosine alleviated the symptom of the mice induced by H9N2-SIV infection, and increased the viability of the mice. In carnosine intervention group, edema degree of the lung (W/D) was apparently reduced (P<0.05). The pathological changes were alleviated on the 6th and 8th days of the experiment. On the same days, the content of MDA was lower obviously (P<0.05) and the activity of SOD was improved remarkably (P<0.05). On the 4th day of the experiment, the activity of MPO was reduced apparently (P<0.05) and continuously decreased on the 6th and 8th days (P<0.05). CONCLUSION: Carnosine protects the mice from acute lung injury induced by H9N2-SIV infection and increases the viability by reducing the content of MDA, lowering the activity of MPO, increasing the activity of SOD and inhibiting the production of free radicals and lipid peroxidation.     

Dynamic observation of asthma model induced by allergen in mice from acute inflammation to chronic remodeling

AIM: To dynamically observe and compare the relative changes of the indexes from the process of acute inflammation to chronic remodeling in asthmatic mice induced by ovalbumin (OVA).METHODS: Female BALB/c mice (n=60) were randomly divided into normal control group and asthma group. The mice in asthma group were sensitized and challenged by OVA, while the mice in normal group received equal volume of normal saline (NS). The challenge was performed for 3 consecutive days from the 21th day to observe the response of acute inflammation, and then the mice in different groups were challenged once per week for 5 weeks. Detailed comparisons of the dynamic changes of cell infiltration, cytokine expression and airway remodeling were conducted.RESULTS: Compared with NS group, the mice in OVA group showed a predominantly eosinophilic infiltration into the airway lumen, increased production of Th2-type cytokines, secretion of epithelial mucus and deposition of subepithelial collagen. In OVA challenge groups, the levels of inflammatory cells and inflammatory factors were remarkably higher in 24 d group, whereas the most obvious changes of goblet cell hyperplasia and airway remodeling were observed in 52 d group.CONCLUSION: Acute asthma model is sufficiently induced by 3 consecutive days of OVA challenge protocol, which is accompanied with high levels of inflammatory cells and inflammatory factors. The OVA challenge protocol once per week for 5 weeks could induce a chronic asthma model with obvious airway remodeling.     

Effect of endothelin-1 on inflammation and oxidative stress in COPD

AIM:To investigate the effect of endothelin-1 on inflammation and oxidative stress in chronic obstructive pulmonary disease (COPD). METHODS:Healthy non-smokers (30 cases), healthy smokers (30 cases) and COPD patients (29 cases) were collected and induced to produce sputum. The concentration of endothelin-1 in the induced sputum was detected. The model of emphysema was established by cigarette smoke extract to stimulate SD rats. Endothelin A receptor antagonist BQ123 and non-selective endothelin receptor antagonist bosentan were used to intervene with the model rats. The experiment was divided into control group, cigarette-treated group, selective antagonist group and non-selective antagonist group. The protein levels of cleaved caspase-3 in the lung tissue were determined by Western blot. Gelatin zymography was used to analyze the activity of matrix metalloproteinase-2 (MMP-2) and MMP-9 in the lung tissue. The levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were measured by ELISA. The bioantioxidant power (BAP) was detected by BAP assay kit. RESULTS:The concentrations of endothelin-1 in induced sputum of healthy smokers and COPD patients were significantly higher than that of healthy non-smokers (P<0.05), and the level of endothelin-1 in COPD patients was significantly higher than that in healthy smokers (P<0.05). The levels of cleaved caspase-3, MMP-2, MMP-9, TNF-α and IL-1β in the lung tissues from cigarette-treated group were significantly higher than those in control group (P<0.05). The endothelin A receptor antagonist significantly inhibited the levels of cleaved caspase-3, MMP-2, MMP-9, TNF-α and IL-1β (P<0.05). The serum BAP in cigarette-treated group was significantly lower than that in control group (P<0.05). However, endothelin A receptor antagonist significantly increased serum BAP (P<0.05). CONCLUSION:Endothelin-1 may play an important role in the development and progression of COPD through regulating apoptosis, matrix metalloproteinase activity, inflammation and oxidative stress.     

Influence of Cordyceps sinensis on cytokine profile of dendritic cells in chronic obstructive pulmonary rat model

AIM: To investigate the effect of Cordyceps sinensis (CS) on dendritic cells (DCs) in the rat model of chronic obstructive pulmonary disease (COPD). METHODS: Eighteen Sprague-Dawley male rats were randomly divided into 3 groups: control group, COPD group and CS group.The rats in the latter 2 groups were exposed to cigarette smoking for 8 weeks with (CS group) or without (COPD group) CS treatment. The rats in control group were maintained under normal condition. After 8 weeks,the histological changes of the right lung were observed under microscope. The DCs from the 3 groups were harvested and the supernatants of DCs were analyzed for the levels of TNF-α and IL-12 p70 by commercially available ELISA kit. The DCs were then washed and cocultured in vitro with autologous T cells purified by a nylon cotton column. The supernatants of DCs-T coculture were collected after 72 h incubation, and analyzed for the levels of interleukin-5 (IL-5) and interferon-γ (IFN-γ) by ELISA. RESULTS: Analysis of the rat lung parenchyma revealed a significant decrease in the mean alveolar number, an indicator of alveolar density, in COPD group (38±16) and CS group (48±9) in comparison with control group (62±8). The mean alveolar number tended to be increased in CS group than that in COPD group, although this difference did not achieve statistical significance (P>0.05). The concentrations of TNF-α and IL-12 p70 in the culture supernatants of DCs and IFN-γ in the supernatants of DCs-T cocluture were up-regulated in CS group as compared with those in COPD group and control group (P<0.05). The level of IL-5 in the DCs-T coculture supernatants of the 3 groups did not show differences with statistical significance (P>0.05). CONCLUSION: The therapeutic effects of CS on COPD rats may be related to modulation of Th1 and Th2 cell functions. This effect is probably mediated through IL-12 p70 produced by DCs and Th1 cytokine IFN-γ produced by autologous T cells.