Pulmonary Protective Functions of Rare Ginsenoside Rg4 on Particulate Matter-induced Inflammatory Responses

Inhalation of fine particulate matter (PM_2.5) is associated with an increase in lung injury caused by the loss of integrity of the vascular barrier. The rare ginsenoside Rg4 is a main protopanaxatriol type ginsenoside of black ginseng (BG). The aim of this study was to investigate the beneficial effects of Rg4 on PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation. Permeability, leukocyte migration, activation of proinflammatory proteins, generation of reactive oxygen species (ROS), and histology were examined in PM_2.5-treated EC and mice. Rg4 significantly scavenged PM_2.5-induced ROS, inhibited ROS-induced activation of p38 mitogen-activated protein kinase (MAPK), activated Akt in purified pulmonary endothelial cells, which helped maintain endothelial integrity. Further, Rg4 reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in bronchoalveolar lavage fluids in PM-induced mouse lung tissues. Data suggested that Rg4 might exhibit protective effects in PM-induced inflammatory lung injury and vascular hyperpermeability.