Effect of Toll-like receptor 4 signal transduction on airway inflammation in infant asthmatic rat

AIM: To study the change and regulatory mechanism of Toll-like receptor 4 (TLR4) on eosinophil (EOS) apoptosis. METHODS: Twenty-seven SD rats were randomly divided into control group (A), asthma group (B) and dexamethasone group (D). Asthmatic model rats were sensitized and repeatedly exposed to aerosolized ovalbumin. Pulmonary tissues were observed under light microscope (LM). The inflammatory cells in BALF were counted. The levels of IL-10 in serum were measured by ELISA. Expressions of TLR4 mRNA were tested by hybridization. The apoptotic EOS was detected by TUNEL.RESULTS: (1) LM showed that inflammatory cells infiltrated around the bronchus, airway mucous plug in group B, obviously lightened in group D. (2) Inflammatory cells count in BALF: the total cellular score, EOS absolute count and EOS% in group B were significantly increased (P<0.01). Compared to group B, a significant decrease in group D was observed (P<0.01). (3) The level of IL-10 in group B was significantly higher than that in group A and in group D (P<0.01). (4) No significant difference (P>0.05) of TLR4 mRNA expression was observed between group A and group B. However, that in group D were significantly increased (P< 0.01). (5) Percentages of apoptotic EOS in group B were significantly lower than those in group A (P<0.01), those in group D were significantly increased (P<0.01). A significant correlation between TLR4 mRNA and apoptotic EOS (r=0.612, P<0.01) was observed. CONCLUSION: Dexamethasone can increase IL-10 secretion, induce EOS apoptosis, which may correlate with TLR4 signal transduction.     

Effect of dexamethasone on the adrenomedullin and its gene expression in lung tissue of asthmatic rats

AIM: To study the effect of dexamethasone (DEX) on the adrenomedullin (ADM) and its gene expression in lung tissue of asthmatic rats. METHODS: 30 healthy male SD rats were randomly divided into three groups (10 for each). The asthmatic model was established by ovalbumin inhalation and injection. The mRNA expression of ADM was examined by RT-PCR and the protein expression was detected by immunohistochemical method. The airway wall thickness, the airway smooth muscle (ASM) thickness and pulmonary tissue changes were observed under light microscope. RESULTS: The expression of ADM mRNA and protein in the asthma group A were higher than those in the control group(group C) (P<0.05), indicating that the moderate expression of ADM in asthmatic rat lung tissue is compensatory. The expression was significantly higher in DEX group (group B) than that in group A (P<0.01), indicating that DEX stimulated the expression of ADM mRNA and protein in lung tissue of asthmatic rats. CONCLUSION: The remarkable expression of ADM after the therapy of dexamethasone is one of its therapeutic mechanisms.     

Protective effects and mechanism of astragalus injection on asthmatic rats

AIM: To explore the protective effects and mechanism of astragalus injection on asthmatic rats.METHODS: OVA was injected intraperitoneally and inhaled to produce the asthmatic model.Forty rats were randomly divided into five groups: control group,asthma group and astragalus groups of high,medium and low dose.The concentrations of IL-4,IFN-γ in BALF,the expression of IL-4 mRNA,IFN-γ mRNA and phospho-p38 MAPK in lung tissues were respectively measured by ELISA,RT-PCR and Western blotting.The number of inflammatory cells in BALF and histropathology changes were observed.RESULTS: In asthmatic group,the number of inflammatory cells and the concentrations of IL-4 in BALF and the expression of IL-4 mRNA,phospho-p38 MAPK in lung tissue were higher,but IFN-γ and IFN-γ mRNA were lower than those in normal control rats (P<0.01).In astragalus group,the number of inflammatory cells,the concentrations of IL-4 in BALF and the expression of IL-4 mRNA,phospho-p38 MAPK in lung tissue were lower,but IFN-γ and IFN-γ mRNA were higher than those in normal control rats (P<0.01),and histropathology damage was alleviated significantly.The efficacies in the astragalus groups of high,medium and low dose were similar,which no significant difference was observed among them.There were positive correlations between the expression of 〖JP3〗phospho-p38 MAPK and the number of eosinophil,the concentration of IL-4,IL-4 mRNA (r=0.63,r=0.69,r=0.71,〖JP〗 P<0.01),and negative correlations between the expression of phospho-p38 MAPK and IFN-γ and IFN-γ mRNA (r=-0.65,r=-0.68,P<0.01).CONCLUSION: p38 MAPK may play a role in pathological process of asthma.Astragalus effectively treats asthma by inhibiting the expression of phospho-p38 MAPK,correcting the inbalance of IFN-γ/ IL-4 and decreasing the number of inflammatory cells.     

Effects of PFOA exposure on inflammatory mediators IL-4, IFN-γ and glucocorticoid receptor in asthmatic mice

AIM: To investigate the effects of perfluorooctanoic acid (PFOA) exposure on the changes of asthmatic mouse airway inflammation, inflammatory mediators interleukin-4 (IL-4) and interferon-γ (IFN-γ) in serum, and glucocorticoid receptor (GR) expression in the lung tissue.METHODS: BALB/c mice (n=30) were randomly divided into 5 groups:normal control (C) group, asthma (A) group, asthma+low-dose PFOA (AP10) group, asthma+ mode-rate-dose PFOA (AP50) group and asthma+high-dose PFOA (AP100) group. Asthma model and PFOA exposure model of mice were established according to the grouping. The animals were sacrificed and their lungs were collected for HE staining, transmission electron microscopy, Western blot and immunohistochemical staining. ELISA was applied to detect the levels of IL-4 and IFN-γ in the serum.RESULTS: HE staining of the lungs showed that the asthmatic mice, compared with the normal control mice, had obvious mucus secretion around the airways and infiltration of inflammatory cells around airways and blood vessels, and the effects were much more marked in AP groups. Ultrastructural alteration of the lung tissues in the asthmatic mice were indicated by transmission electron microscopy. Compared with C group, the results of ELISA in A group and AP groups proved that IL-4 in the serum was increased and IFN-γ was decreased significantly (P<0.05). Compare with A group, IL-4 was significantly increased and IFN-γ was decreased in AP100 group (P<0.05), and no difference of those between AP10 group and AP50 group was found. The results of Western blot indicated that GR protein expression in the asthmatic mice were decreased compare with the normal mice (P<0.05), and no difference of that among A group and AP groups was observed. Immunohistochemical staining manifested that GR protein was mainly located in the cytoplasm of bronchial columnar epithelial cells, airway smooth muscle cells and vascular smooth muscle cells.CONCLUSION: Acute airway PFOA exposure in asthmatic mice dose-dependently exacebates lung inflammation by inducing Th2 type immune responses, promotes infiltration of inflammatory cells and mucus secretion around the airways and blood vessels, and destroys the ultrastructure of the lung tissues.     

Expression of IFN-γ, IL-4 and IL-17A in asthmatic mice vaccinated with BCG and HepB in neonatal period

AIM: To investigate the expression of IFN-γ, IL-4 and IL-17A in asthmatic mice vaccinated with bacillus Calmette-Guérin (BCG) and hepatitis B (HepB) in the neonatal period. METHODS: BALB/c mice were randomly divided into BGG+HepB+ovalbumin (OVA) group (B/H/O group), B/O group, H/O group, B/H group, OVA group, BCG group, HepB group and normal saline (NS) group (n=6). The mice in B/H/O group and B/H group at 0, 7 and 14 d received subcutaneous injection of 1×10⁵ CFU BCG for 3 times, while at 0 and 28 d received intramuscular injection of 1.5 μg HepB on the hindlimb twice. The mice in other groups were individually vaccinated with BCG or HepB. OVA sensitization and aerosol inhalation were performed to establish the asthma model. The lung tissues were collected for HE staining. Bronchoalveolar lavage fluid (BALF) and peripheral blood (PB) were collected, and the number of eosinophils (EOS) in BALF was counted. The serum levels of IFN-γ and IL-4, and the level of IL-17A in lung tissue homogenate were measured by ELISA. RESULTS: The pathological changes of the lung in OVA group, B/O group, B/H/O group and H/O group were observed. There were extensive inflammatory cell infiltration around the bronchus, and epithe-lial cell hypertrophy. Those in B/H/O group and H/O group were worse than those in OVA group, while those in B/O group was better than those in OVA group. Total BALF cell counts in B/H/O group, B/O group and H/O group were decreased (P<0.05) as compared with OVA group. The BALF EOS count in B/H/O group was higher than that in B/H group, that in B/O group was higher than that in BCG group, and that in H/O group was higher than that in HepB groups (P<0.05). Compared with H/O group, OVA group and NS group, the serum IFN-γ/IL-4 ratio in HepB group was increased (P<0.05), and compared with B/H/O group, B/O group, OVA group and NS group, that in B/H group was also increased (P<0.05). Compared with OVA group, the level of IL-17A in the lung tissues of B/H/O group and B/O group was decreased (P<0.05), and compared with B/O group, that in B/H/O group was further decreased (P<0.05). CONCLUSION: Combined vaccination of BCG and HepB reduces the inflammotory responses in the lung tissues of asthmatic mice. The mechanism may be related with the decrease in the release of IL-4, the increase in IFN-γ/IL-4, and the inhibition of IL-17A expression.     

Effects of Jiedu-Qingfei mixture on NF-κB and p38 MAPK pathways in lung tissues of rats with Mycoplasma pneumoniae infection

AIM: To observe the therapeutic effect of Jiedu-Qingfei mixture on Mycoplasma pneumoniae (MP)-infected rat lung tissues and to explore its mechanism. METHODS: SD rats (n=40) were randomly divided into 4 groups:blank control group, model group, Jiedu-Qingfei group and positive control group, with 10 rats in each group. The rats in experimental groups were slowly dripped with 1×10⁹ CFU/L MP solution into their nostrils for 4 d. One rat in each group was sacrificed for MP nucleic acid detection at the second day after inoculation, and the other rats were given gavage therapy. The rats in blank control group and model group were intragastrically given the same volume of normal saline, the rats in Jiedu-Qingfei group were given 8 mL/kg Jiedu-Qingfei mixture daily for 4 weeks, and the rats in psoitive control group were given dexmethasone sodium phosphate (0.5 mg·kg^-1·d^-1). After the experiment, the rats were killed. The serum and bronchoalveolar lavage fluid (BALF) were collected for detecting the levels of interleukin-12 (IL-12), IL-13 and TNF-α by ELISA. The right lung tissues were used for pathological observation and HE staining, while the left lung tissues were used to detect the expression of NF-κB p50, I-κBα and p38 mitogen-activated protein kinase (p38 MAPK) at mRNA and protein levels. RESULTS: The results of MP nucleic acid detection showed that all the rats except blank control group were MP nucleic acid positive, indicating that the rat model of MP infection was successfully established. On the 1st day of the treatment, the pathological scores of the lung tissues in model group and Jiedu-Qingfei group were significantly higher than those in blank control group (P<0.05). After treatment, the pathological scores of the lung tissues in mo-del group were significantly higher than those in blank control group and Jiedu-Qingfei group. The levels of IL-12 in the serum and BALF in model group were significantly lower than those in blank control group after MP infection (P<0.05), while those after treatment with Jiedu-Qingfei mixture were significantly higher than those in model group (P<0.05). The levels of IL-13 and TNF-α in the serum and BALF of MP-infected rats were increased significantly, while those after treatment with Jiedu-Qingfei mixture were significantly lower than those in model group (P<0.05). The mRNA expression levels of NF-κB p50 and p38 MAPK in model group were increased significantly (P<0.01). After treatment, the mRNA expression levels of NF-κB p50 and p38 MAPK were decreased significantly compared with model group (P<0.01). The mRNA expression level of I-κBα in model group was significantly lower than that in control group. After treatment, the mRNA expression of I-κBα in Jiedu-Qingfei group was significantly higher than that in model group (P<0.05). The protein levels of NF-κB p50 and p38 MAPK in the lung tissues of model group were significantly higher than those of blank control group. After treatment, the protein expression of NF-κB p50 and p38 MAPK was decreased significantly. The protein level of I-κBα in model group was significantly lower than that in blank control group, and after treatment with Jiedu-Qingfei mixture, the protein expression level of I-κBα was increased significantly (P<0.05). CONCLUSION: Jiedu-Qingfei mixture may attenuate lung tissue inflammation caused by MP through NF-κB and p38 MAPK pathways.     

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.     

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.     

Effects of mitogen activated protein kinase on γ-glutamylcysteine synthase in lung of guinea pigs with bronchial asthma

AIM: To investigate the effects of mitogen activated protein kinase on γ-glutamylcysteine synthase (γ-GCS) in lung of guinea pigs with bronchial asthma.METHODS: Twenty adult male guinea pigs were divided into asthmatic group and control group (10 in each group).Asthmatic model was established by ovalbumin intraperitoneal injection combined with inhalation.The numbers of total and inflammation cells in bronchoalveolar lavage fluid (BALF) were measured.The γ-GCS-h mRNA in lung tissue was examined by in situ hybridization and RT-PCR.Immunohistochemistry was used to detecte the expression of γ-GCS,phosphorylated extracellular signal regulated kinase (p-ERK),phosphrylated c-Jun amino terminal kinase (p-JNK) and phosphorylated p38 (p-p38) in lung tissues.Western blotting was conducted to determine the expressions of p-ERK,p-JNK and p-p38 in lung tissue.The activity of γ-GCS was measured by coupled enzyme assay.RESULTS: (1) The total cell number and number of eosinophils in BALF of asthmatic group were significantly higher than those in control group (P<0.01).(2) Immunohistochemistry indicated that the p-ERK,p-p38,p-JNK and γ-GCS were stronger expressed in asthmatic group than those in control group (P<0.01).Western blotting also discovered that the expressions of p-ERK,p-JNK and p-p38 in lung tissue of asthmatic group were stronger than those in control group.(3) Both in situ hybridization and RT-PCR analysis showed that the expression of γ-GCS-h mRNA was more positive in asthmatic group compared with control group (P <0.01).(4) The activity of γ-GCS of asthmatic group was significantly higher than that in control group (P<0.01).(5) Linear correlation analysis indicated that in lung tissue of guinea pig with asthma,p-ERK and p-p38 markedly positive correlated with γ-GCS-h mRAN and γ-GCS protein.No relationship between p-JNK and γ-GCS-h mRAN,γ-GCS protein was observed.CONCLUSION: The expressions of p-ERK,p-p38,p-JNK and γ-GCS increase in lung of guinea pigs with bronchial asthma.p-ERK and p-p38 may positively regulate the expression of γ-GCS.     

Changes of nitric oxide synthase and nitric oxide in lung of smoking rats

AIM:To observe the changes of iNOS and eNOS in lung tissue and NO in bronchoalveolar lavage fluid (BALF) in smoking rats.METHODS:80 Wistar rats were divided into control, smoking group, L-NIL group and L-NAME group (rats were exposed to smoke and injected (i.p.) with selective iNOS inhibitor L-NIL or NOS inhibitor L-NAME). iNOS and eNOS protein levels in whole lung were detected by immunohistochemical staining, and NOS mRNA was quantified using RT-PCR. In addition, NO₂^-/NO₃^- was determined using Griess assay.RESULTS:The expression of iNOS mRNA and protein in smoking rats increased, the expression of eNOS mRNA and eNOS protein decreased, and the total cell count and the level of NO₂^-/NO₃^-in BALF increased(P＜0.05). In vivo, L-NIL reduced the total cell count and NO₂^-/NO₃^- in BALF (P＜0.05), while L-NAME had no effect on them.CONCLUSION:Cigarette smoke increased expression of iNOS mRNA and protein and decreased expression of eNOS mRNA and protein. The large amount of NO generated by iNOS may amplify inflammation in lung tissue.     

Effects of glucocorticoid on miRNA-155 expression in CD4+T cells of asthmatic mice

AIM:To investigate the effects of glucocorticoid on the regulation of microRNA-155 (miRNA-155) expression in the CD4⁺ T cells of asthmatic mice. METHODS:The ovalbumin (OVA)-induced asthma mouse model was established and the mice were treated with glucocorticoid. The effects of glucocorticoid on the pulmpnary histopathological changes, the expression of miRNA-155 in the lung tissues and CD4⁺T cells, and the levels of cytokines in the bronchoal-veolar lavage fluid (BALF) were evaluated. RESULTS:The results of RT-qPCR showed that the expressions of miRNA-155 in the lung tissues and CD4⁺T cells from the spleen of asthmatic mice were significantly increased, and the level of miRNA-155 in the CD4⁺T cells was significantly increased with the increase in the allergen exposure time (P<0.01). HE and PAS staining showed that OVA significantly increased inflammatory cell infiltration as compared with control group, and the peribronchial and perivascular inflammation and mucus secretion of proliferative goblet cells were significantly reduced after glucocorticoid treatment. Glucocorticoid treatment inhibited the increase in the proportion of CD4⁺ CD8^- cells in the spleen and decreased the accumulation of CD4⁺ T cells in the lung tissues of asthmatic mice (P<0.01). After glucocorticoid treatment, the levels of interleukin-4 (IL-4), IL-5 and IL-13 in BALF were decreased, while the level of interferon-γ was increased significantly (P<0.01). CONCLUSION:Glucocorticoid reduces the accumulation of CD4⁺ T cells and inhibits the expression of miRNA-155 in the lung tissues and spleen CD4⁺ T cells of asthmatic mice.     

Expression of PPARγ, Nrf2 and γ-GCS-h in inflammatory cells in bronchoalveolar lavage fluid of guinea pigs with bronchial asthma

AIM: To investigate the expression of PPARγ and Nrf2/γ-GCS-h in inflammatory cells in bronchoalveolar lavage fluid(BALF) of guinea pig with bronchial asthma of acute episode, and to explore the roles of PPARγ on Nrf2/γ-GCS-h expression. METHODS: Forty adult male guinea pigs were randomly divided into 4 groups (10 guinea pigs in each group): control group (group A), asthmatic group (group B), dexamethasone treatment group (group C) and rogridone treatment group (group D). The asthmatic model was established by an ovalbumin challenge method. BALF was collected, and the total cell count and the proportion of the inflammatory cells were measured. After centrifugation, the concentrations of ROS and MDA in the clear supernatant were detected. The methods of in situ hybridization and immunohistochemistry were used for detecting the expression of PPARγ and Nrf2/γ-GCS-h at mRNA and protein levels. RESULTS: The proportion of eosinophils (EOS) in BALF in group B was significantly higher than that in groups A, C and D (P<0.01). The concentrations of ROS and MDA in BALF of group B was the highest. The difference of ROS and MDA was statistically significant (all P<0.05) as compared to the control. The results of immunohistochemistry and in situ hybridization indicated that the A value was the lowest in group B as compared to that in groups A, C and D (all P<0.01). In group B, the positive correlations were observed between PPARγ and Nrf2/γ-GCS-h, between γ-GCS-h and Nrf2. A negative correlation between the proportion of EOS in BALF and the expression of PPARγ and Nrf2/γ-GCS-h was also observed (all P<0.05). CONCLUSION: In acute asthmatic models induced by ovalbumin, the expression of PPARγ and Nrf2/γ-GCS-h is decreased, and PPARγ may up-regulate the expression of Nrf2/γ-GCS-h to inhibit the inflammatory and oxidative reactions, indicating a new way for prevention and treatment of bronchial asthma.     

Isorhamnetin inhibits ovalbumin-induced pulmonary inflammation in asthmatic mice

AIM To investigate the effect of isorhamnetin on pulmonary inflammation in asthmatic mice and to analyze its primary mechanism. METHODS BALB/c mice were randomly divided into normal control group, asthma model group, isorhamnetin low-dose （50 mg/kg） treatment group and isorhamnetin high-dose （150 mg/kg） treatment group. Ovalbumin （OVA） was used to establish a mouse asthma model. HE staining and PAS staining were used to observe the pathological changes of lung tissue. The contents of cysteinyl leukotriene1 （CysLT1）, cystelinyl leukotriene receptor 1 （CysLTR1）, interleukin-4 （IL-4）, IL-5, IL-13 and tumor necrosis factor-α （TNF-α） in bronchoalveolar lavage fluid （BALF） were measured by ELISA. The expression of nuclear factor of activated T cells 4（NFATc4） in lung tissue was detected by immunohistochemical staining. The protein expression of NFATc4, intercellular cell adhesion molecule-1 （ICAM-1） and vascular cell adhesion molecule-1 （VCAM-1） was determined by Western blot. RESULTS Isorhamnetin improved histopathological changes in OVA-induced asthma model mice, reduced the contents of CysLT1, CysLTR1, IL-4, IL-5, IL-13 and TNF-α in BALF, and reduced NFATc4, ICAM-1 and VCAM-1 expression in lung tissue （P<0.05）. CONCLUSION Isorhamnetin inhibits the inflammatory response of lung tissue in asthmatic model mice, and the mechanism may be related to the inhibition of the calcineurin/NFATc4 signaling pathway.     

Effects of Maxing-Shigan decoction on airway remodeling and expression of MMP-9 and TIMP-1 in lung tissues of asthmatic mice

AIM:To investigate the effects of Maxing-Shigan decoction on airway remodeling and expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the lung tissues of asthmatic mice, and to explore its possible mechanism in treatment of asthma. METHODS:The BALB/c mice were divided into blank control group, model group, low-dose Maxing-Shigan decoction group, middle-dose Maxing-Shigan decoction group, high-dose Maxing-Shigan decoction group and positive control group. The mice were sensitized and challenged with ovalbumin to establish asthma model. The mice in blank control group and model group were given saline by oral administration before 30 min of suscitation. The mice in low-dose, middle-dose and high-dose Maxing-Shigan decoction groups were given Maxing-Shigan decoction at 5.0 g/kg, 10.0 g/kg and 20.0 g/kg, respectively, by oral administration before 30 min of suscitation. The mice in positive control group was given dexamethasone at 0.005 g/kg by oral administration before 30 min of suscitation. After consecutive administration for 7 d, the variations of airway responsiveness, the percentage of the goblet cells, the collagen deposition, and the eosinophil (EOS) counts in bronchoalveolar lavage fluid (BALF) of each group were observed. The protein levels of MMP-9 and TIMP-1 in the lung tissues were determined by ELISA and Western blot. The mRNA expression of MMP-9 and TIMP-1 was detected by RT-qPCR. RESULTS:Compared with blank control group, the airway responsiveness, the goblet cell percentage, the collagen deposition, the EOS counts in BALF, the protein levels of MMP-9 and TIMP-1, and the mRNA expression of MMP-9 and TIMP-1 were significantly increased in model group (P<0.01). Compared with model group, all of the indexes were reversed in low-dose, middle-dose and high-dose Maxing-Shigan decoction groups and positive control group (P<0.05 or P<0.01). CONCLUSION:Maxing-Shigan decoction improves airway remodeling in asthma model mice by down-regulating the expression of MMP-9 and TIMP-1.     

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.