Strain difference in an allergic asthma model in rats.

A new rat asthma model was devised, and with the model, allergic bronchoconstrictor responses and effects of disodium cromoglycate (DSCG) were compared among Wistar, Lewis and Fischer 344 rats. Rats were actively sensitized with DNP-Ascaris antigen (DNP-As) and killed Bordetella pertussis vaccine. After eight days, asthmatic response was provoked by inhalation of DNP-As. The bronchomotor response was measured with a modified Konzett-Rössler method in diaphragm-sectioned rats. The inhalation of DNP-As using a newly devised apparatus caused a marked asthmatic response with negligible effects on systemic blood pressure and heart rate. The extent of the bronchoconstriction provoked was of the following order: Wistar greater than Lewis = Fischer 344. There was no relationship between the individual 48 hr PCA titer and the bronchoconstriction that occurred in any strain of rats. The bronchoconstrictions were inhibited by DSCG (10 mg/kg, i.v.) and the inhibition ratios were 28%, 36% and 33% in Wistar, Lewis and Fischer 344 rats, respectively. The inhibitions were statistically significant in the latter two strains. Fischer 344 rats were more susceptible to the damage resulting from the operative procedures. The above findings suggest that Lewis rats are the most suitable among the above strains as a model for studying the effects of antiallergic agents.