Lipopeptide Biosurfactant Produced by Acinetobacter junii B6 Attenuates Lung Inflammatory, Oxidative, and Histopathological Alterations due to Asthma in Rats

The two main characteristics of asthma pathogenesis are severe inflammation and excessive oxidative stress production. Biosurfactant (BS), as surface-active metabolites synthesized by microorganisms, is mainly isolated from bacterial strains and was previously reported to have various therapeutic functions, such as providing antioxidant and anti-inflammatory benefits. Our study aimed to investigate the anti-inflammatory and anti-oxidative role of lipopeptide BS using an experimental asthma model in rats. Lipopeptide BS was isolated from Acinetobacter junii B6. In vivo, male rats were randomly assigned into four groups (7 rats in each group); normal control rats (CTL), non-treated asthmatic rats, asthmatic rats received BS, and asthmatic rats treated with budesonide (positive control). Administration of ovalbumin (OVA) to rats was used to induce an allergic asthma model. At the end of the induction period, the ELISA method was used to determine the inflammatory and OS markers in BALF and lung tissue. Moreover, total protein and IgE concentrations were determined in lung tissue, BALF, and serum, respectively. A histological study of lung tissue was performed using H&E staining. Treatment with Lipopeptide BS decreased inflammatory cell count in lung tissue and also reduced the level of cytokines and oxidant parameters (TNF-α, IL-1β, IL-6 and MDA, total protein, nitrite) in both BALF and lung tissue. Also, the IgE level in serum was reduced by Lipopeptide BS administration. In contrast, the level of IL-10, TAC level, SOD, and GPX activity was elevated in both BALF and lung tissue following Lipopeptide BS administration. The histological evaluation indicated that Lipopeptide BS considerably inhibited histopathological changes, airway and epithelial damage, emphysema, and goblet cell hyperplasia in the tissue.

The preventive effect of Lipopeptide BS is potentially promising in asthma treatment through reducing histological changes, inflammation, and oxidative stress.