Korean Red Ginseng water extract inhibits cadmium-induced lung injury via suppressing MAPK/ERK1/2/AP-1 pathway

BACKGROUND: Few studies reported the therapeutic effect of Korean Red Ginseng (KRG) in lung inflammatory diseases. However, the anti-inflammatory role and underlying molecular in cadmium-induced lung injury have been poorly understood, directly linked to chronic lung diseases (CLDs): chronic obstructive pulmonary disease (COPD), cancer etc. Therefore, in this study we aim to investigate the therapeutic activities of water extract of KRG (KRG-WE) in mouse cadmium-induced lung injury model. METHOD: The anti-inflammatory roles and underlying mechanisms of KRG-WE were evaluated in vitro under cadmium-stimulated lung epithelial cells (A549) and HEK293T cell line and in vivo in cadmium-induced lung injury mouse model using semi-quantitative polymerase chain reaction (RT-PCR), quantitative real-time PCR (qPCR), luciferase assay, immunoblotting, and FACS. RESULTS: KRG-WE strongly ameliorated the symptoms of CdSO(4)-induced lung injury in mice according to total cell number in bronchoalveolar lavage fluid (BALF) and severity scores as well as cytokine levels. KRG-WE significantly suppressed the upregulation of inflammatory signaling comprising mitogen-activated protein kinases (MAPK) and their upstream enzymes. In in vitro study, KRG-WE suppressed expression of interleukin (IL)-6, matrix metalloproteinase (MMP)-2, and IL-8 while promoting recovery in CdSO(4)-treated A549 cells. Similarly, KRG-WE reduced phosphorylation of MAPK and c-Jun/c-Fos in cadmium-exposed A549 cells. CONCLUSION: KRG-WE was found to attenuate symptoms of cadmium-induced lung injury and reduce the expression of inflammatory genes by suppression of MAPK/AP-1-mediated pathway.