The Change Of Pulmonary Surfactant System In Asthma Rat And The Protective Effects Of Ambroxol

【Objective】 To investigate the relationship between pulmonary surfactant(PS) system and asthma, the present study was designed to observe the change of PS system in asthma rat. To evaluate the protective effects of Ambroxol in asthma, we observed the effects of Ambroxol treatment on PS system and airway inflammation of chronic asthmatic rat.【Methods】 The rat asthma model were established with ovalbumin sensitize and challenge method. 3 group were studied: control group, asthma group and Ambroxol treated group(treated group):1. The rats were challenged with aerosol of ovalbumin or saline and the change of intratracheal pressure of sensitized rats. 2. Bronchial alveolar lavage (BLA) were performed after challenge. The total and differential white blood cell counts of bronchial alveolar lavage fluid (BALF) were carried out. Lung tissue section were stained with hematoxylin and eosin for general morphology and Alician Blue-Periodic Acid Schiff (AB-PAS) for identification of goblet cell. The pathologic changes were observed inender optical microscope. 3.PS was extracted from bronchial alveolar lavage fluid (BALF) using chloroform/methanol and the amount of total phospholipid (TPL). disaturated phosphatidylcholine (DSPC), total protein (TP) were determined. Surface activity of PS in BALF were measured with Wilhelmy film balance; 4.The concentration of pulmonary surfactant protein A(SP-A) in the BALF and the distribution of SP-A in the lung were assayed by Western Blot and immumohistochemistry(IHC) methods, respectively, 5. The bivariate co-relationships between the surface activity of PS in BALF and the amounts of DSPC,TP,SP-A in BALF were analysed.【Result】1. The intratracheal pressure of sensitized rats in 3 groups before antigen challenge were similar. The intratracheal pressure of rats in asthmagroup significantly increased after antigen challenge and the percentages of intratracheal pressure increasing were higher than those in the control group(119.2％±30.1％ vs 18.4％±4.7％,P<0.01).The percentages of intratracheal pressure increasing in treated group were significantly decreased than those in the asthma group(58.8％±19.0％ vs 119.2％±30.1％,P<0.01). 2. The total cell numberS were significantly increased in the asthma group than those in the control group(P<0.001)The number of eosinophils and netrophils were significantly increased in the asthma group than those in the control group and the number of macrophages and lymphocytes likewise. The total cell numbers were significantly decreased in the treated group than those in the asthma group(P<0.001).The bronchoconstriction and inflammatory cells infiltration surrounding bronchi in the asthma group were observed. Goblet cell hyperplasia(GCH)and mucus retarded in airway lumen in the asthma group were also observed. The airway inflammation and GCH were significantly alleviated in treated group. 3. TPL and DSPC in asthma group were similar to those in the control group(P>0.05). The concentration of TP in BALF increased obviously in asthma group than those in other two groups(p<0.01).We also found that the of PS in BALF had a significantly decrease in asthma group. It indicated an increase in minimum surface tension(STmin) and a decrease in stability index(SI). The concentration of TPL in BALF were much higher in treated group than those in the of other two groups(p<0.01). The concentration of DSPC in BALF were much higher in treated group than those in the asthma groups(p<0.01). The PS in BALF of treated group revealed a better surface activity. 4. When compared with normal rats, there were marked reductions of SP-A levels in BALF of asthmatic rats (p<0.01).The SP-A levels in BALF of treated rats were higher than those of asthmatic rats. 5. The surface activity correlated positively with the DSPC and SP-A levels in BALF and correlated negatively with the TP levels in BALF.【Conclusions】1.These results indicated the involvement of pulmonary surfactant system in the allerigic bronchial inflammation of asthmat...