Ginsenoside Rb1 protects from Staphylococcus aureus-induced oxidative damage and apoptosis through endoplasmic reticulum-stress and death receptor-mediated pathways

Acute lung injury (ALI) is acute uncontrolled inflammation of lung tissue that leads to high fatality both in human and animals. Staphylococcus aureus (S. aureus) could be an opportunistic, versatile bacterial etiology of ALI. Ginsenoside Rb1 (Rb1) is extracted from the Panax ginseng, which displays a wide range of biological and pharmacological effects. However, protective effects of Rb1 in S. aureus-induced ALI though endoplasmic reticulum (ER) stress and death receptor-mediated pathways have not yet been reported. Therefore, present study was planned with the aims to investigate the antioxidant and anti-apoptotic properties of Rb1 through regulation of ER stress as well as death receptor-mediated pathways in ALI induced by S. aureus in mice. In this study, four groups of healthy Kunming mice (n = 48) were used. The S. aureus (80 µl; 1 ×107 CFU/10 µl) was administered intranasally to establish mice model of ALI. After 24 h of onset of S. aureus-induced ALI, the mice were injected thrice with Rb1 (40 mg/kg) intraperitoneally six hours apart. Histopathology, enzyme linked immunosorbent assay (ELISA), real time quantitative polymerase chain reaction (RT-qPCR), Immunohistochemistry and western blotting assay were employed in the current study. Our results suggested that Rb1 administration save lungs from pulmonary injury by reducing wet to dry (W/D) ratio, protein levels, total cells, neutrophilic count, reactive oxygen species (ROS), myeloperoxidase (MPO), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx)1 depletion. Meanwhile, Rb1 therapy ameliorated histopathology alteration of lung tissue and pro-inflammatory cytokines secretion. The gene expression of ER stress marker (PERK, AFT-6, IRE1 and CHOP) were upregulated markedly (P