Effects of xiao-qing-long-tang (XQLT) on bronchoconstriction and airway eosinophil infiltration in ovalbumin-sensitized guinea pigs: in vivo and in vitro studies.
BACKGROUND
Xiao-qing-long-tang (XQLT sho-seiru-to), a traditional Chinese medicine, has been used to treat patients with bronchial asthma in Oriental countries for several centuries. However, the therapeutic mechanisms of this Chinese medicine remain a matter of considerable debate. Therefore, a series of experiments using ovalbumin-sensitized guinea pigs was performed to elucidate the possible antiasthmatic effect of XQLT.


METHODS
The effect of XQLT on ovalbumin-induced airway inflammation in a guinea pig model of allergic asthma was examined, and early and late asthmatic responses were measured in terms of airway resistance and extent of eosinophil infiltration. Furthermore, the bronchorelaxing effect of XQLT was measured in isolated guinea pig trachea.


RESULTS
XQLT significantly inhibited the antigen-induced immediate asthmatic response (IAR) and late asthmatic response (LAR) in actively sensitized guinea pigs. Cumulative administration of XQLT caused concentration-dependent relaxation of the carbachol-precontracted guinea pig trachea. The bronchorelaxing effect of XQLT was reversed by ICI-118551, a selective beta2-adrenoceptor antagonist. Furthermore, examination of bronchoalveolar lavage fluid (BALF) revealed that XQLT significantly suppressed the increase in eosinophils (24 h after antigen challenge) in the airway. In addition, XQLT significantly attenuated the increase in eosinophils at 1, 6, 24, 48, and 72 h after antigen challenge when it was administered once daily from the day of sensitization to the day of challenge. Histopathologic examination results showed that XQLT suppressed eosinophil infiltration into lung tissue.


CONCLUSIONS
These results demonstrate that the antiasthmatic effects of XQLT appear to be partly mediated by stimulation of beta2-adrenoceptors, leading to bronchorelaxation, and that XQLT inhibits the infiltration of eosinophils into the airway. Thus, XQLT may be useful for the prevention or treatment of asthma.
Kao
S T
ST
Institute of Chinese Medical Science, China Medical College, No. 91 Hsueh Shih Road, Taichung, Taiwan, ROC.
Lin
C S
CS
Hsieh
C C
CC
Hsieh
W T
WT
Lin
J G
JG
D000818:Animals; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology; D016535:Bronchial Hyperreactivity / Q000188:drug therapy* / Q000209:etiology / Q000276:immunology; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D016084:Bronchoconstriction / Q000187:drug effects*; D002452:Cell Count; D004195:Disease Models, Animal; D004365:Drugs, Chinese Herbal / Q000627:therapeutic use; D004804:Eosinophils / Q000276:immunology*; D006168:Guinea Pigs; D007114:Immunization; D008297:Male; D010047:Ovalbumin / Q000276:immunology*; D013997:Time Factors; D014132:Trachea / Q000187:drug effects* / Q000276:immunology
D018927:Anti-Asthmatic Agents; D004365:Drugs, Chinese Herbal; C090832:sho-seiryu-to; D010047:Ovalbumin