Standardized myrtol attenuates lipopolysaccharide induced acute lung injury in mice

Context: Standardized myrtol, an essential oil containing primarily cineole, limonene and α-pinene, has been used for treating nasosinusitis, bronchitis and chronic obstructive pulmonary disease (COPD).

Objective: To investigate the effects of standardized myrtol in a model of acute lung injury (ALI) induced by lipopolysaccharides (LPS).

Materials and methods: Male BALB/c mice were treated with standardized myrtol for 1.5?h prior to exposure of atomized LPS. Six hours after LPS challenge, lung injury was determined by the neutrophil recruitment, cytokine levels and total protein concentration in the bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) activity in the lung tissue. Additionally, pathological changes and NF-κB activation in the lung were examined by haematoxylin and eosin staining and western blot, respectively.

Results: In LPS-challenged mice, standardized myrtol at a dose of 1200?mg/kg significantly inhibited the neutrophile counts (from 820.97?±?142.44 to 280.42?±?65.45, 10³/mL), protein concentration (from 0.331?±?0.02 to 0.183?±?0.01, mg/mL) and inflammatory cytokines level (TNF-α: from 6072.70?±?748.40 to 2317.70?±?500.14, ng/mL; IL-6: from 1184.85?±?143.58 to 509.57?±?133.03, ng/mL) in BALF. Standardized myrtol also attenuated LPS-induced MPO activity (from 0.82?±?0.04 to 0.48?±?0.06, U/g) and pathological changes (lung injury score: from 11.67?±?0.33 to 7.83?±?0.79) in the lung. Further study demonstrated that standardized myrtol prevented LPS-induced NF-κB activation in lung tissues.

Discussion and conclusion: Together, these data suggest that standardized myrtol has the potential to protect against LPS-induced airway inflammation in a model of ALI.