Crocin from saffron ameliorates allergic airway inflammation through NF-κB, IL-17, and Nrf2/HO-1 signaling pathways in mice.

Objectives: Asthma is a complex inflammatory disorder with the infiltration of inflammatory cells in the lung airways. Saffron's active component, crocin, has been proven to possess anti-inflammatory and anti-oxidant effects. The objective of this current study was to explore the impact of crocin on NF-kB and nuclear erythroid 2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1) signaling pathways in ovalbumin (OVA)-sensitized mice, aiming to understand its mechanism.

Materials And Methods: Four different groups were formed by dividing forty male BALB/C mice: control group, OVA-sensitized group (OVA), OVA combined with crocin 30 mg/kg (OVA-Cr30), and the OVA combined with crocin 60 mg/kg (OVA-Cr60). In order to determine the total number of WBC and inflammatory cells infiltrating the lung, we utilized the bronchoalveolar lavage fluid for counting purposes. The mRNA and protein levels of Nrf2, HO-1, IL-17, and NF-κB in lung tissue were assessed through real-time PCR and western blot techniques.

Results: Crocin significantly prevented the increase of total WBC and inflammatory cells in the lung tissue (<0.001 for all) and histopathological changes in OVA-sensitized mice. Furthermore, crocin displayed suppressive effects on the enhancement of NF-kB (<0.01) and IL-17 (<0.05) mRNA and protein levels in OVA-sensitized mice while preserving Nrf2 (<0.01) and HO-1 (<0.05) expression levels. Crocin effects became increasingly apparent when utilized at high concentrations.

Conclusion: Crocin decreased airway inflammation, partially by inhibiting NF-κB and IL-17 and up-regulating Nrf2/HO-1 mRNA and protein expression levels.