[The relationship between interleukin-8 and airway hyperresponsiveness]

Abstract

Objective: To explore the relationship between interleukin-8 (IL-8) and airway hyperresponsiveness (AHR) of asthma.

Method: IL-8 at a dose of 0.5 microgram/kg or 5 micrograms/kg was administered intranasally to guinea-pigs twice a week for 3 weeks. 24 hours after the last administration, airway responsiveness was measured as an overall index of airway response to increasing concentrations of inhaled histamine (25, 50, 100 and 200 micrograms/ml) and the numbers of different inflammatory cells in bronchoalveolar lavage fluid (BALF) was counted.

Results: The IL-8 treatment significantly enhanced airway responsiveness to histamine in a dose-dependent manner (P < 0.05 or 0.01) and induced a significant influx of neutrophils in BALF (P < 0.01), and there are many neutrophils within airway wall but not control animals treated with phosphate buffered saline (PBS).

Conclusion: The IL-8 given into the airways can produce neutrophil inflammation of the airways and induce AHR, it may play an important role in asthma, especially in the development of AHR.