Effects of 5-HT and electrolytes on the airway remodeling of bronchial asthma in guinea pigs

AIM: To explore the effects of 5-HT and electrolytes on the airway remodeling in guinea pigs with bronchial asthma.METHODS: 70 guinea pigs were divided into 7 groups: control group, model group, continued model group, 5-HT group, anti-5-HT group, high Mg2+ group, low Mg2+ group.Remodeling model was established with ovalbumin.RESULTS: ① In model group, 5-HT of serum and thickness of airway walls were significantly increased compared with control group (P<0.05,P<0.01).② In continued model group, 5-HT and thickness of airway walls were significantly increased compared with model group (P<0.05, P<0.01).③ In 5-HT group, thicknesses of airway walls were significantly increased compared with continued model group (P<0.05).④ In anti-5-HT group, thicknesses of airway walls were significantly decreased compared with continued model group (P<0.05).⑤ In high Mg2+ group, thicknesses of airway walls were significantly decreased compared with continued model group (P<0.05).⑥ In low Mg2+ group, thickness of airway smooth muscle was significantly increased compared with continued model group (P<0.05).⑦ With the aggravation or alleviation of airway remodeling, concentration of Ca2+ in serum was upward or downward.However, concentration of PO3-4 was downward or upward.⑧ Veriety of Na+, K+, Cl- was no significant difference among groups.⑨ Concentration of 5-HT in serum was corrected with that of Ca2+.CONCLUSIONS: ① 5-HT mediates airway remodeling of asthma in guinea pigs whereas Mg2+ may play a regulatory role.② Increase in Ca2+ and decrease in PO3+4 may promote the airway remodeling of asthma whereas Na+, K+, Cl- may not play any role.③ Concentration of 5-HT in serum was corrected with that of Ca2+ in airway remodeling of asthma.     

Role of calcineurin in airway remodeling in guinea pig model of asthma

AIM:To investigate the role of calcineurin (CaN) in airway remodeling in guinea pig model of asthma.METHODS:Male guinea pigs were randomly divided into three groups: control, asthma group and CsA group. The following parameters were measured: 1. The protein content, cell count and differential count of BALF; 2. The amount of [³H]-TdR incorporation into central airway smooth muscle; 3. The mean thickness of airway wall and airway smooth muscle of small airwaysl; 4.CaN activity of trachea and lung tissue.RESULTS:1. The protein content, cell count and eosinophil of BALF in CsA group were 46%, 51% and 60% lower than those in asthma group, respectively (P＜0.01); 2. [³H]-TdR incorporation in CsA group was 22% lower than that in asthma group (P＜0.05);3. The mean thickness of airway wall and airway smooth muscle were 34% and 37% less in CsA group than those in asthma group, respectively (P＜0.01); 4. CaN activity of lung tissue and trachea were 52% and 44% lower in CsA group than those in asthma group, respectively (P＜0.01).CONCLUSION:CsA reduced airway remodeling in guinea pig model of asthma, indicating the role of CaN in the airway remodeling.     

Effect of mesenteric lymph duct ligation on actue lung injury in rats

AIM：To explore the effect of mesenteric lymph duct ligation against actue lung injury (ALI) in rats.METHODS：45 Wistar rats were divided into three groups：the ligation group,the non-ligation group and sham operated group,and the two-hit model was established by hemorrhage and LPS injection.Mesenteric lymph was diverted by ligating mesenteric lymph duct in ligation group.All rats facilitated blood withdrawal for blood sample to arterial gas analysis after 24 hours.Then the WBC,NO,NOS,MDA,SOD and lung permeability index (LPI) were determined in bronchoalveolar lavage fluid (BALF),the MPO and ATPase activity were determined in lung homogenate.The ultrastructure was also observed.RESULTS：After two-hit,the PaCO2,the total cells and PMN,the NO2-/NO3-,NOS and MDA content in BALF and MPO activity in lung homogenate and LPI in non-ligation group were significantly increased than those in sham operated group.PaO2 and pH in arterial blood,SOD in BALF and the ATPase in lung homogenate were significantly lower (P<0.01 or P<0.05).The total cells and PMN,MDA,NO2-/NO3- in BALF,LPI in ligation group were significantly increased than those in sham operated group,and SOD in BALF was significantly lower (P<0.01 or P<0.05).The pH and PaO2 in arterial blood,the ATPase in lung homogenate in ligation group were significantly increased than those in non-ligation group,and the PaCO2,the total cells,PMN,NO2-/NO3-,NOS,MDA in BALF,LPI,and MPO in lung homogenate in ligation group were significantly lower than those in non-ligation group (P<0.01 or P<0.05).The injury of pulmonary vascular endothelium in ligation group was lighter than that in non-ligation group.CONCLUSION：The ligation of mesenteric lymph duct attenuates the ALI of rats.Mesenteric lymph might play an important role in the pathogenesis of ALI.     

Effect of airway remodeling on airway responsiveness in asthmatic guinea pigs

AIM: To establish a guinea pig asthma model and to evaluate the effect of airway remodeling on airway responsiveness. METHODS: The guinea pig asthma model was established by ovalbumin (OVA) sensitization and challenge repeatedly. Bronchial provocation tests were conducted through intravenous injection of acetylcholine. The airway morphologic parameters were measured by computer image analysis system. White blood cells and the differential count in bronchoalveolar lavage fluid (BALF) were examined. RESULTS: The resistance of airway was increased significantly after 4 weeks of OVA exposure, but the increase disappeared upon prolonged exposure. After 8 weeks of OVA exposure, fiber tissue in large airway was increased, and the thickness of smooth muscle layer of small airway was enlarged, as compared with that in control animals. CONCLUSION: Airway responsiveness has changed after prolonged OVA exposure in guinea pigs. This change is related to airway remodeling.     

Effects of electrolyzed free radicals on endothelium of isolated guinea pig coronary and epithelium of airway tube

AIM and METHODS:To study the damage effects of free radicals from electrolyzed krebs solution(direct current,10 mA,1-2 min) on isolated guinea pig coronary and airway tube. RESULTS:In Langendorff’s perfused guinea pig hearts,the electrolyzed free radicals increased coronary perfusion pressure(4.4±1.2) kPa,inhibited myocyte contractility [(0.8±0.8) g vs (2 9±0 6) g, P< 0.05],increased TBARS level and decreased SOD activity.In isolated perfused lungs of guinia pig,electrolyzed Krebs solution promoted significantly the airway perfusion pressure [(0.03±0.01) kPa vs (2.20±0.29) kPa, P< 0.01] and histamine reactivity [(0.65±0.37) kPa vs (2.05±0.25) kPa, P< 0.01]. Hydroxyl radicals scavenger DMSO and natural medicine gypenosides prevented the effects of oxygen free radicals. CONCLUSION: These results indicated that the free radicals by electrolyzation could induce damages of coronary endothelium and airway epithelium.     

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 histamine and hypoxia on eNOS gene expression in cultured porcine pulmonary and aorta endothelial cells

AIM: To investigate the effect of histamine and hypoxia on the expression of eNOS mRNA and protein in cultured porcine pulmonary artery and aorta endothelial cells. METHODS: Semi-quantitative RT-PCR and immuno-cytochemistry were used. RESULTS: (1) Histamine increased eNOS mRNA expression in a dose-and time dependent manner. For pulmonary endothelial cells, the effect reached peak when exposed to 10-5 mol/L histamine in 24 h. eNOS mRNA level was increased to 178.2%±7.7% (P<0.01) compared with control. eNOS protein was also enhanced to 173%±47% (P<0.01) compared with control. For aorta endothelial cells, the effect reach peak when exposed to 10-6 mol/L histamine in 24 h. The eNOS mRNA level was increased to 177.4%±14.3% (P<0.01) compared with control. The eNOS protein was also enhanced to 165%±54% (P<0.01). (2) The eNOS mRNA was enhanced in pulmonary endothelial cells after exposed to hypoxia for 12 h and reached peak in 24 h, increasing to 151.0%±9.1% (P<0.01). The protein expression was also enhanced to 216%±44% (P<0.01) compared with control. But there was no significant change in eNOS mRNA and protein expression in aorta endothelial cells during hypoxia. CONCLUSION: The experiments show that histamine increases the endothelial eNOS expression in both pulmonary and aorta endothelial cells, whereas hypoxia only increases eNOS expression in pulmonary endothelial cells. This may account partly for the different responses of pulmonary circulation and systemic circulation to hypoxia.     

Role of three kinds of potassium channel in airway hyperresponsiveness of asthmatic guinea pigs

AIM: To investigate the role of Ca2+-activated, delayed-rectifier and ATP sensitive K+ channel (KCa, Kdr, KATP) in airway hyperresponsiveness of asthmatic guinea pigs. METHODS: The method of recording the tone of isolated trachea rings was performed, and the changes of dose-response curves of trachea rings to histamine caused by different K+ channel blockade were investigated. RESULTS: (1) After inhibition of KCa by tetraethylammonium (TEA), the dose-response curve of trachea rings to histamine did not change in control group, while the maximal contraction of trachea rings to 10-4 mol/L and 10-3 mol/L histamine decreased significantly (P<0.01) and dose-response curve shifted down significantly in asthmatic group. (2) After inhibition of Kdr by 4-aminopyridine (4-AP), the maximal contraction to 10-3 mol/L histamine decreased (P<0.05) and dose-response curve shifted down in control group, the response to 10-4 mol/L and 10-3 mol/L histamine decreased significantly (P<0.01) and dose-response curve shifted down more significantly in asthmatic group and the decrease of the latter was more significant than that in control group (P<0.05); (3) The dose-response curves did not change by KATP blocker glibenclamide (Glib) in both control and asthmatic group. CONCLUSION: The depression of both KCa and Kdr might mediate the airway hyperresponsiveness in asthmatic guinea pigs, whereas the KATP doesn't take part in it.     

Valsartan protects a rat model of adriamycin-induced dilated cardiomyopathy from left ventricular remodeling and failure

AIM: To investigate whether and how AT1 receptor blocker， valsartan， attenuates left ventricular remodeling and failure in a rat model of adriamycin（ADR）-induced dilated cardiomyopathy. METHODS: Weight-matched adult male Wistar rats were randomly divided into 3 groups as follows: 1) the ADR group, in which 2.5 mg/kg of ADR was weekly injected via a tail vein for 10 weeks (n=25); 2) concomitant AT1 receptor blocker valsartan and ADR, in which valsartan was administered by daily gavage at a dose of 30 mg·kg-1·d-1 (n=10); 3) control group (n=10). Hemodynamics and echocardiographic measurements were obtained at 12 weeks after treatment. Finally, left ventricle (LV) samples were collected at 12 weeks. The hydroxyproline content was determined by the methods of chloramines T. The expression of MMP-2, MMP-9 and tissue inhibitors of metalloproteinase-1 (TIMP-1) were measured by Western blotting. MMP-2 and -9 gelatinolytic activities were measured by gelatin zymography. RESULTS: Mortality was significantly lower in valsartan -treated rats than that in ADR rats (20% versus 40%, P<0.01). The dilatation of LV cavity was significantly attenuated in ADR-induced dilated cardiomyopathy rats given valsartan. Valsartan partially normalized LV contractile function, which was significantly reduced in ADR rats. The hydroxyproline content was increased in ADR-DCM group and significantly reduced by valsartan treatment (P<0.01). The protein levels of LV MMP-2 and MMP-9 were increased in ADR rats and attenuated by valsartan treatment (both P<0.01). However, no change in TIMP-1 was observed (P>0.05). The activities of LV myocardial MMP-2 and -9 gelatinolytic were increased significantly in ADR rats (both P<0.01) and attenuated by valsartan treatment (both P<0.01). CONCLUSION: Pretreatment with AT1 receptor blocker valsartan attenuates left ventricular remodeling and failure in a rat model of adriamycin-induced dilated cardiomyopathy.     

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 poly(ADP-ribose) polymerase on the response of guinea pig tracheas induced by peroxynitrite in vitro

AIM and METHODS: to elucidater the effect of poly(ADP-ribose) polymerase(PARP) on tracheal hyperreactivity of guinea - pig induced by peroxynitrite, the responses of guinea pig tracheas to histamine af- ter incubation with peroxynitrite in the absence and presence of 3 - aminobenzamide(3 - AB), a highly selective inhibitor for PARP, were observed in vitro. RESULTS: The exposure of tracheal strips to peroxynitrite led to epithelial damage and hyperreacitivity to histamine, both of which were reversed by 3 - AB(lmmol/L or 5mmol/L), whereas incubation of tracheal strips with 3 - AB(5mmol/L) had no effect on the reponses. CONCLUSION: PARP is involved in the epithelial damage and hyperreactivity of guinea - pig tracheas induced by peroxynitrite. The results suggested that inhibition of excessive activation of PARP may represent a novel strategy for the prevention and therapy of airway hyperreactivity in asthma.     

Phosphodiesterase 3 inhibitor attenuates cough response in a sensitized guinea pig model

AIM: To investigate the effects of selective phosphodiesterase 3 inhibitor olprinone on cough response in guinea pigs sensitized and challenged with ovalbumin.METHODS: Forty sensitized guinea pigs were randomly divided into control (n=10), challenged (n=10), olprinone (n=10) and aminophylline group (n=10). Two hours after challenged with the aerosol of 1% ovalbumin or saline, animals were intraperitoneally injected either with saline, 25 mg/kg of olprinone or 25 mg/kg aminophylline. At 24 h, the injection was repeated with 2.5 mg/kg and 25 mg/kg olprinone or 2.5 mg/kg and 25 mg/kg aminophylline respectively in olprinone and aminophylline group, cough response to inhaled capsaicin and airway responsiveness to methacholine (PC150) were measured. Then, total cell number and differential counts were analyzed in bronchoalveolar lavage fluid. RESULTS: The cough frequency was (5±2) times/3 min in control group and (24±3) times/3 min in challenged group (P<0.05), while PC150 was (659±57) mg/L in control group and (238±67) mg/L in challenged group (P<0.05). 25 mg/kg olprinone significantly inhibited the augmented cough response and airway hyperresponsiveness, the cough frequency and PC150 were (15±2) times/3 min and (580±45) mg/L (P<0.05), which differed significantly from (18±2) times/3 min and (438±52) mg/L in aminophilline group (P<0.05). However, olprinone failed to reverse the elevated total cell number and percentage of eosinophils in bronchoalveolar lavage fluid from guinea pigs challenged with ovalbumin (P>0.05).CONCLUSION: Phosphodiesterase 3 inhibitor attenuates cough response associated with eosinophilic airway inflammation by bronchodilatory effect.     

Effects of Wnt/β-catenin signal pathway on asthma airway remodeling

AIM: To explore the effect of Wnt/β-catenin signaling pathway in airway smooth muscle cells (ASMC) on asthmatic airway remodeling.METHODS: The asthmatic airway remodeling model in rats was established and the ASMC was isolated and cultured. The protein expression of β-catenin, glycogen synthase kinase-3β (GSK-3β), c-Myc and cyclin D1 in the ASMC was determined by Western blot. After depressing the interaction between β-catenin and p300/CBP, the cell activity was measured by CCK-8 assay and the change of cell cycle distribution was analyzed by flow cytometry. Meanwhile, the protein expression of c-Myc and cyclin D1 in the ASMC was determined by Western blot after inhibiting P38 mitogen-activated protein kinase (MAPK) activity.RESULTS: The protein levels of β-catenin, c-Myc and cyclin D1 were significantly increased in asthma group while the protein level of GSK-3β was decreased in the same group (P<0.05). After depressing the interaction between β-catenin and p300/CBP, the cell activity of ASMC was decreased in asthma group compared with control group (P<0.05), and the change of the cell cycle distribution in asthma group was also more obvious (P<0.05). After inhibiting P38 MAPK activity, the protein levels of c-Myc and cyclin D1 were all decreased compared with control group in ASMC asthma and control rats (P<0.05).CONCLUSION: Wnt/β-catenin signaling pathway may participates in airway remodeling in asthma by increasing the protein expression of c-Myc and cyclin D1, reacting with the P38 MAPK signaling pathway and regulating the growth of ASMC.     

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.     

Effects of CpG-oligodeoxynucleotides and dexamethasone on airway remodeling and expression of MMP-9 and TIMP-1 in murine model of chronic asthma

AIM: To observe the changes of airway inflammation and remodeling in a murine model of chronic asthma with CpG- oligodeoxynucleotides(CpG ODN) and dexamethasone (DXM) treatments.METHODS: BALB/c mice were sensitized and repeatedly challenged with ovalbumin.Pathological slides were prepared from left lung and stained with hematoxylin-eosin.WAmus (smooth muscle area),Wamuc (mucous area) and WAi (inner wall area) of the airway were measured and standardized by Pbm (basement membrane perimeter). The areas of collagen Ⅰand Ⅲ in the lung tissue were determined by using a Sirius red-polarizing microscopy morphometry method.Expressions of matrix metalloprotease-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were detected by immunohistochemistry.RESULTS: WAmus/Pbm,WAmuc/Pbm and WAi/Pbm decreased significantly in CpG ODN and DXM treated group when compared with asthma group (P<0.05).No statistical significance between CpG ODN and DXM treated group was observed (P>0.05).Collagen deposition in asthma group increased more than that in CpG ODN and DXM treated group (P<0.05).The expressions of MMP-9 and TIMP-1 were much higher in asthma group than those in CpG ODN and DXM treated group (P<0.05).It had no statistical significance between CpG ODN and DXM treated group (P>0.05).CONCLUSION: Airway remodeling occurrs in the chronic asthma.Early intervention with steroid or CpG might partially inhibit its process via lowering expressions of MMP-9 and TIMP-1 in chronic asthma.     

Effect of BQ123 on the voltage-gated K+ current of pulmonary artery smooth muscle cells of rats exposed to chronic hypoxia

AIM:To study the effect of BQ123 on voltage-gated K+ current in pulmonary artery smooth muscle cells (PASMCs) from chronic hypoxic rats. METHODS:Twelve age and body weight matched Wistar rats were randomly divided into control and chronic hypoxic group. Single PASMCs were obtained with acute enzyme (collagnaseⅠ plus papain) dispersing method. Using the whole cell patch-clamp technique in freshly isolated PASMCs from normorxic and hypoxic rats, the effects of ET-1 and BQ123, a selective ETA receptor antagonist, on voltage-gated K+ current were recorded. RESULTS:(1) ET-1 (10-8 mol·L-1) caused inhibition of K+ current in PASMCs from normoxic and hypoxic rats. The effect of ET-1 on K+ current in PASMCs from hypoxic rats was greater than that from normoxic rats ［+50 mV, percent inhibition were (71.04±6.58)% and (60.21±5.32)%, respectively, P<0.01, n=6］. (2) In normoxic PASMCs, neither BQ123 alone produced influence on the IKV (P>0.05, n=5), nor ETA receptor blockade had change of ET-1 mediated IKV inhibition. (3) In chronic hypoxic PASMCs, BQ123 significantly reduced the effect of ET-1 mediated IKV inhibition, from (28.49±6.69) pA/pF to (74.19±9.74) pA/pF at +50 mV (P<0.01, n=6). CONCLUSION:In normoxic condition, the effect of ET-1 on IKV of PASMCs is not mediated by BQ123, a selective ETA receptor antagonist. During exposure to chronic hypoxia, the inhibition of ET-1 on IKV of PASMCs is partly mediated by BQ123, namely, ETA receptor mediates the effect of ET-1 on IKV of chronic hypoxic PASMCs.     

Inhibitory effect of ground dragon on the expression of α-SMA and FN in the lung tissue of mouse with asthma

AIM: To investigate the inhibitory effect of ground dragon on the expression of α-SMA and FN in the lung tissue with asthma. METHODS: The BALB/c mice were divided into four groups: control group (group A, n=20), asthmatic model group (group B, n=20), large-dose ground dragon treatment group (group C, n=20) and low-dose ground dragon treatment group (group D, n=20). To establish a mouse model of chronic asthma, we sensitized the mouse with 0.02% ovalbumin (OVA) by intraperitoneal injection, and stimulated the mice with 1% OVA by atomization. The treatment groups were given ground dragon before stimulation every time. After the last time of stimulation, the mice were subjected to laboratory tests. Inflammatory cells in bronchoalveolar lavage fluid were counted. Total level of IgE in serum was detected by ELISA. FN mRNA and α-SMA mRNA in the lung tissue were measured by RT-PCR and AlphaImager 2200 semi-quantitation analysis system. Expressions of FN and α-SMA were measured by the method of two-step immunohistochemistry and leica QWIN V3 analysis system. RESULTS: (1) Compared with those in group A, the expressions of α-SMA and FN in group B were significantly increased (P<0.01). Compared with group B, those in group C were significantly decreased (P<0.01), while those in group D were slightly decreased (P>0.05). (2) Compared with those in group A, the expression levels of α-SMA mRNA and FN mRNA in group B had a great increase (P<0.01). There was a notably decreases of α-SMA mRNA and FN mRNA levels in group C, compared with group B (P<0.01). However, α-SMA and FN mRNA level in group D was just a slightly decreased, compared with group B (P>0.05). CONCLUSION: The ground dragon inhibits α-SMA and FN expression in the lung tissue of mice with chronic asthma, indicating that ground dragon may inhibit airway remodeling in asthma through the inhibition of α-SMA and FN expressions.     

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.