STRAIN-RELATED DIFFERENCES IN SEPHADEX BEAD-INDUCED AIRWAY HYPERRESPONSIVENESS AND INFLAMMATION IN RATS

Objective: The aim of this study was to compare Sephadex G-200 (Sephad ex)-induced airway hyperresponsiveness (AHR) and pulmonary eosinophili a among some rat strains. Materials: Sprague-Dawley (SD), Brown-Norway (BN), Fischer 344 (Fischer), Lewis and Wistar-Kyoto (WKY) rats were u sed. Methods: Sephadex (0.5 mg/animal) was intravenously administered on days 0, 2 and 5. Measurement of AHR using serotonin and bronchoalve olar lavage (BAL) was performed on day 7. Results: The Lewis strain ex hibited significant AHR to Sephadex but the BN, Fischer and WKY strain s did not. Additionally, the degree of AHR in Lewis rats was smaller t han in SD rats throughout the study. Eosinophils in BAL fluid, however , increased in each strain, and the magnitude of the response was BN > Lewis > WKY > Fischer. Both the AHR and pulmonary eosinophilia in Lew is rats were inhibited by dexamethasone (0.1 mg/kg, p.o. x3). Conclusi on: These results indicate that the Lewis rat is a useful strain for a nalysis of the mechanism of Sephadex-induced AKR and airway inflammati on.