Anti-inflammatory effects of brucea javanica oil via inhibition of NF-κB activation.

OBJECTIVE

As a traditional herbal medicine extracted from the seeds of oil (BJO) has been clinically used to treat wart, chronic gastroenteritis and a variety of malignant tumors, including gastrointestinal cancer and lung cancer. We have recently reported the anti-tumor role and possible molecular mechanisms of BJO in treatment of lung cancer. However, it remains elusive whether BJO also has an anti-inflammatory effect.

METHODS

The pneumonia-related inflammatory factors of macrophages under LPS treatment were investigated by real-time PCR and ELISA assays. LPS-induced acute pneumonia rat model was established. Hematoxylin and eosin (HE) examination was performed to detect histopathological changes in the lung tissues. Real-time PCR and ELISA assays were also used to detect the pneumonia-related inflammatory factors in lung tissues.

RESULTS

LPS-induced expression and secretion of pneumonia-related inflammatory factors (TNF-α, IL-1β, IL-6 and IL-8) were significantly suppressed by BJO in a concentration-dependent manner in RAW264.7 cells. However, BJO did not affect cell proliferation and survival rate. Further mechanistic studies revealed that BJO down-regulated the phosphorylation of IκB and p65, thereby inhibiting NF-κB pathway of macrophages and exerting its anti-inflammatory function. Western blot analysis showed that the phosphorylation levels of IκB and p65 were significantly up-regulated while the protein level of IκB was inhibited upon LPS stimulation in RAW264.7 cells and in lung tissue. Notably, LPS stimulation levels of IκB and p65 were effectively reversed under BJO co-treatment. The expression level of p65 was not influenced by LPS and BJO treatment. HE staining results showed that BJO can reduce the infiltration of inflammatory cells in lung.

CONCLUSION

BJO can reduce the level of inflammatory factors in lung tissue, which provides a theoretical basis for BJO emulsion as an adjuvant therapy for pneumonia.