Anti-asthma potential of crocin and its effect on MAPK signaling pathway in a murine model of allergic airway disease

Context: Crocin, a diterpenoid glucoside, has multitudinous activities such as anti-inflammation, anti-allergy, anti-oxidation and relaxing smooth muscles. Objective: In this study, the potential of crocin as an anti-asthma agent was investigated in a murine model. Materials and methods: BALB/c mice were sensitized and challenged by ovalbumin (OVA) to induce allergic airway inflammation, with crocin administered one hour before every OVA challenge. Airway hyper-reactivity was evaluated by lung function analysis systems. Leukocyte counts in bronchoalveolar lavage fluid (BALF) were measured by a hemocytometer and Diff-Quick-stained smears. Lung tissues were stained with hematoxylin-eosin, Congo red and methylene blue for histopathological inspection. Inflammatory mediators in serum, BALF and lung were measured by ELISA or RT-PCR. Effects of crocin on MAPK signaling pathways were investigated by western blot analysis. Results: Crocin significantly suppressed airway inflammation and hyper-reactivity, reduced levels of BALF interleukin (IL-4), IL-5, IL-13 and tryptase, lung eosinophil peroxidase and serum OVA-specific IgE, and inhibited the expression of lung eotaxin, p-ERK, p-JNK and p-p38 in the OVA-challenged mice. Conclusions: These results demonstrated that the suppression of crocin on airway inflammation and hyper-reactivity in a murine model, thus crocin might have a great potential to be a candidate for the treatment of asthma.