Background and objective: Airway inflammation is a well-characterized pathological feature of asthma. The effects of two natural adjuvants on lungs of sensitized guinea pigs were examined.
Methods: The responses of guinea pig tracheal chains, WBC, differential WBC in lung lavage and IL-4 and interferon (IFN)-gamma levels in serum were examined in control guinea pigs and four treatment groups, including sensitized animals (S) and sensitized animals treated with the adjuvants PC (S + PC), G2 (S + G2) or both adjuvants (S + PCG2) (n = 6). Animals were sensitized by injection and inhalation of ovalbumin.
Results: Tracheal responsiveness to methacholine (concentration of methacholine causing 50% of maximum contraction), WBC, eosinophil, neutrophil and basophil numbers were increased and lymphocyte numbers were decreased in lung lavage of sensitized animals compared with the control group (P < 0.01 to P < 0.001). However, G2 adjuvant and the combination of G2 and PC adjuvants caused a significant reduction in tracheal responsiveness (P < 0.01 and P < 0.001, respectively). In addition both adjuvants prevented changes in WBC (P < 0.001 for both). Both adjuvants and the combination prevented changes in eosinophil, neutrophil and basophil numbers in lung lavage of sensitized animals (P < 0.05 to P < 0.001). The adjuvants also prevented changes in IL-4 but increased IFN-gamma levels in all treatment groups compared with group S (P < 0.001 for all cases).
Conclusions: These results indicate that the two natural adjuvants (especially G2 adjuvant) and their combination have therapeutic effects, with reduction in tracheal responsiveness and WBC in lung lavage of sensitized guinea pigs.