| Objective: Bronchial asthma is a chronic allergic disease -caused by various factors and characterized by reversible airway obstruction, airway hyperreactivity and air tube inflammation. The global morbidity of childhood asthma has been increasing in recent years and become an important issue undermining the health of childhood. Jiawei-maxingshigan decotion (MG) is my tutor's clinical prescription. The decotion is very effective in controlling the pediatric asthma attacks with a clinical advantage. The experimental study mainly focuses on the effects of MG on airway inflammation and AHR in asthmatic rats and researches in the anti-inflammatory mechanism in order to provide theoretical foundation for the clinic application for the treatment of pediatric asthma.Method: 60 male Sprague-Dawley rats were randomly divided into six groups: normal control group, asthmatic model group, MG small-dose group, MG large-dose group, dexametha- sone treated group, MG and dexamethasone treated group(Uni- on group), with each group having 10 rats. Then each of them was injected with lml of 10% OVA. After 21 days, they were inhaled with 1% OVA for 20 minutes each day for 7 days and given medicine at the same time. 24 hours after last provocation, all the rats were killed. In order to observe the changes of lung histomorphology, we adopted the method of transmission electron microscope histochemistry to observe the ultrastructure change of rats of various groups. Peripheral eosinophil count was detected by conventional counting method. The concentrations of NO in serum and in pulmonary tissue measured bynitric acid reduction method and ET-1content in plasma and in pulmonary tissue were measured by radioimmunoassay. The protein expressions of iNOS and in the pulmonary tissues of all groups were measured by immunohist- ochemistry.Results1. The effects of MG on pathology morphology in pulmonary tissue in asthmatic ratsNormal group: The structures of bronchial tube and pulmonary tissue are normal and integrated.There were no mucus secretion and no infiltrating of inflammatory cells.Model group: There were lots of inflammatory cells infiltr- ating around bronchi and blood vessels in asthmatic group, such as neutrophils, eosinophils and lymphocytes. The membrane w- as increased thickness.Bronchoconstriction, mucus secretion and proliferation or apoptosis of bronchial cells also emerged.Dexamethasone treated group: The structures of bronchial tube and pulmonary tissue are basicly normal and the epithelium of bronchial tube is basicly complete without exudation in tube.MG large-dose group:The inflammation was improved ob- viously, and the infiltration of inflammatory cells around bronc- hial tube and perivascular was decreased, and the acidophilia g- ranular cells can seldom be seen. the hyperplasia of basilar me- mbrane was to lighten and exudation to be seldom in tube. The mucous epithelium of bronchial tube is basicly complete and regularityMG small-dose group:The infiltration of inflammatory cells was decreased or moderate, and some acidophilia granular cells and lymphocytes can still be seen. The damage of bronchial tube mucous epithelium was moderate, and the proliferation of shaped cells was not obvious.Union group: The mucous epithelium of bronchial tube is basicly complete. The membrane increased thickness was obviously decreased and the inflammatory cellsinfiltration can seldom be seen.2. The effect of the count of EOS in peripheral blood of every group asthmatic ratsThe model group's number of EOS in peripheral blood total count significantly increased compared with the normal group(P<0.001). MG and dexamethasone and drug combination ameliorate the number of EOS in peripheral blood, there was a significant difference from the model group(P<0.01), but there were no significant differences among the four drug treated groups(P>0.05). 3. The effect of the concentrations of ET-1 in plasma and in pulmonary tissueThe concentrations of ET-1 in plasma of the model group was significantly higher compared with those of the normal group (P<0.001). After drug treatment, the concentrations of ET-1 were decreased, there were a significant difference from those of the model group(P<0.01). The concentrations of ET-1 of MG large-dose were significantly different from those of MG small-dose group (P<0.01). The concentrations of ET-1 MG large-dose and dexamethasone group did not show any significant difference (P>0.05). The concentrations of ET-1 of MG large-dose were significantly different from those of drug combination group (P<0.05). The concentrations of ET-1 of dexamethasone and drug combination group were no significant difference(P>0.05).The concentrations of ET-1 in pulmonary tissue of the model group were significantly higher compared with those of the normal group(P<0.001). After drug treatment, the conceration of ET-1 were decreased, there was a significant difference compared with those of the model group (P<0.01). The concentrations of ET-1 of MG large-dose were significantly different from those of MG small-dose group (P<0.01). The concentrations of ET-1 MG large-dose group and dexamethaso- ne and drug combination were not significantly different (P>0.05).4. The effect of MG on the concentrations of NO in serum and in pulmonary tissueAfter drug treatment, the concentrations of NO in serum were decreased compared with model group, there were no significant differences of NO observed in serum among normal group, model group and four drug treated groups (P>0.05);The concentrations of NO in pulmonary tissue of model group were significantly higher compared with those of the normal group (P<0.001). After drug treatment, the concentrati- ons of NO in pulmonary tissue were decreased, there was a significant difference compared with those of the model group (P<0.01). The concentrations of NO of dexamethasone group and drug combination were not significantly different(P>0.05). The concentrations of NO of the MG large-dose group were significantly different from those of dexamethasone group (P<0.05). The concentrations of NO of the MG small-dose group were significant different from those of the MG lagre-dose group and dexamethasone and drug combination (P<0.01). The relationship between NO and ET-1 in pulmonary tissue was ob-viously positive correlativity(r=0.689, P<0.001). 5. The effect of MG on the expression of iNOS in asthmatic ratsThe expression of iNOS was significantly higher compared with that of the normal group (P<0.001). After drug treatment, the expression of iNOS was decreased compared with model group. The expressions of iNOS of MG large-dose group and dexamethasone and drug combination group were significant different compared with that of the model group (P<0.01). but there were no sigtnificant differences among the three groups(P<0.05). The expression of iNOS of small-dose group compared with that of the model group was not different (P>0.05). The expression of iNOS of MG large-dose group was significantly different from MG small-dose group(P<0.05).The relationship between iNOS and NO in pulmonary tissue was ob- viously positive correlativity(r=0.619, P<0.001),and between ET-1 in pulmonary tissue was obviously positive correlativity (r=0.744, P<0.001)Conclusion: MG decotion can improve the airway inflammation. The mechanisms relate to control EOS'chemotax- is, promote EOS' apoptosisthe airway inflammation. MG can decrease the level of ET-1 in plasma and in pulmonary tissue, the level of NO in serum and the expression of iNOS of pulmo- nary tissue. MG can control airway inflammation and reduce AHR. It has the effect of immunomo- dulation in asthma.
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