Oleuropein Reduces Mycoplasma pneumonia-Induced Pneumonia in Mice via Down-Regulating the Inflammatory Response

Pneumonia is a common airway inflammatory disease, which is caused by several stimuli. Mycoplasma pneumoniae is the foremost cause of pneumonia, with the clinicopathological features ranging from coughing, fever, and breathing problems. The therapeutic effects of oleuropein were analyzed against M. pneumoniae-induced pneumonia in mice via regulating the inflammatory and oxidative stress responses. Swiss albino mice were challenged with M. pneumoniae (100 µl) through nasal drips for 2 days to initiate pneumonia. The mice were subsequently treated with 20 mg/kg of oleuropein for 3 days. The lung weight, nitric oxide, and myeloperoxidase levels in the mice were estimated. The oxidative stress markers malondialdehyde, superoxide dismutase, and glutathione, as well as inflammatory cytokines, were analyzed. The total cell count and DNA quantity were determined in the bronchoalveolar lavage fluid of the experimental mice. The histopathological analysis was done on lung tissues. The 20 mg/kg of oleuropein effectively reduced the lung weight, nitric oxide, and myeloperoxidase levels in the pneumonia mice. The malondialdehyde was decreased, and superoxide dismutase and glutathione levels were boosted by oleuropein treatment. The levels of inflammatory cytokines, including IL-1, IL-6, IL-8, TNF-α, and NF-κB, were effectively reduced by oleuropein treatment in the pneumonia model mice. Oleuropein also decreased the total cell count and DNA amount in the pneumonia infected mice. The findings of the histopathological analysis revealed a substantial decrease in inflammatory cell infiltration and alveolar damage in the pneumonia model mice. The present results validate the beneficial effects of oleuropein against M. pneumoniae-induced pneumonia in mice. Therefore, oleuropein can be a candidate for the management of pneumonia.