The possibility to monitor longitudinally in no-invasive way the activation of IL-8 in the same mice CF compared to WT after intratracheally challenged with inflammatory stimuli such as: human TNF-alpha, LPS P. aeruginosis and with the culture supernatant obtained from the P. aeruginosa clinical strain VR1 is step a forward in investigating the molecular mechanism linked to cystic fibrosis and with the advantage of reducing the number of animals required. This evidence concerns the gene CXCL8 and cystic fibrosis.