Lipopolysaccharide (LPS) exposure differently affects allergic asthma exacerbations and its amelioration by intranasal curcumin in mice

• Dose and schedule of LPS exposure determines asthma exacerbations.
• Lower dose of LPS exposure is better in exacerbating allergic asthma.
• Enhanced airway inflammations are dominated by eosinophils and neutrophils.
• Th2 cytokine and IgE levels are enhanced after LPS exposure.
• Intranasal curcumin is better in ameliorating the exacerbations than dexamethasone.

AimLipopolysaccharide (LPS) is ubiquitous in the environment and can therefore, exacerbate allergic responses. Studies have suggested immunoregulatory effects of LPS according to route, dose and stage of exposure. Present study has examined whether dose and stage of LPS exposure (during sensitization and challenge with OVA) exacerbates airway inflammations, antigen specific-IgE level, histamine release, Th1/Th2 cytokine response. Further, anti-asthmatic potential of curcumin, through intranasal route has been evaluated for the first time in LPS induced airway inflammation in an ovalbumin (OVA)-challenged mouse asthma model.MethodsBalb/c mice were first sensitized with OVA on 1st and 8th day and exposed to two LPS doses (0.1/1.0 μg) separately on 2nd day and then further exposed to LPS with OVA-aerosol (from 9 to 14 day). Further, lower LPS dose (0.1 μg) was chosen for OVA exposed mouse model of asthma exacerbation study. Intranasal curcumin was administered from 9th to 14th day before every LPS exposure.ResultsExposure to LPS (0.1 μg) exacerbates airway inflammations in terms of IgE level, Th2-cytokine response (IL-4 and IL-5), histamine release, EPO and MPO activities and oxidative stress. Intranasal curcumin has effectively ameliorated airway exacerbations whereas dexamethasone, a known glucocorticosteroid, was not promising as compared to intranasal curcumin.ConclusionSchedule and dose of LPS exposure determines asthma exacerbations and intranasal curcumin could be better immunomodulatory agent in LPS exposed asthma exacerbations.