AIMTo establish an antigen-specific asthmatic model of guinea pig induced by protein antigen extracted from Dermatophagoides farinae (Der f), and study the desensitization of dust mite drops (DMD, extracted from Der f) in a dose progressive manner and long-term sublingual administration.

METHODSTo sensitize the guinea pigs, the protein antigen emulsified in aluminium hydroxide gel was subcutaneously and intraperitoneally injected. To observe early-phase reaction of asthma, lung resistance (R(L)) and lung dynamic compliance (Cdyn) in the sensitized guinea pigs were determined by intravenously injecting antigen. To observe late-phase reaction of asthma, the sensitized guinea pigs were challenged with aerosolized antigen for 7 days. Subsequently, methacholine (Mch) in a cumulative dose-manner induced-airway hyperreactivity (AHR), inflammatory cells numbers in bronchoalveolar lavage fluid (BALF) and pathological changes of lung tissue were measured in the model. From the first day of sensitization, the guinea pigs in treatment group sublingually received DMD in a dose progressive manner. The model group sublingually received equivalent saline. The normal control group did not receive any treatment.

RESULTSThe guinea pigs in model group showed a significant increase in R(L) and decrease in Cdyn, and developed a marked AHR to Mch. The number of total leukocytes and eosinophils increased significantly in BALF. Serious infiltration of eosinophils was observed in pathological section of lung tissue. Compared with model group, DMD treatment group exhibited a significant amelioration for early-phase and late-phase reaction of asthma.

CONCLUSIONDMD in a dose progressive manner and long-term sublingual administration displays a significant desensitization on Der f antigen-specific asthmatic reaction. The results provided experimental evidence for clinical therapy.