Objective: Cigarette smoke exposure is one of the major risk factors for the development of chronic obstructive pulmonary disease (COPD). Ginseng saponin Rb1 (Rb1) is a natural extract from ginseng root with anti-inflammatory and anti-oxidant effects. However, the underlying mechanism of the Rb1 in COPD remains unknown. Therefore, we sought to explore the role of Rb1 in cigarette smoke-induced damage and to reveal the potential mechanism.
Methods: The cell viability and lactose dehydrogenase (LDH) activity were analyzed using cell counting kit-8 (CCK-8) and LDH release assays. We further investigated the inflammation, apoptosis and oxidative stress markers and analyzed the nuclear factor-kappa B (NF-κB) and nuclear factor erythroid-2-related factor 2 (Nrf2) pathways in BEAS-2B cells and COPD rat model following cigarette smoke extract (CSE) exposure.
Results: Our results showed that CSE promoted inflammation, apoptosis and oxidative stress in BEAS-2B cells. Rb1 suppressed the inflammatory response by inhibiting expression of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1β and inhibiting the NF-κB signaling pathway. Rb1 possessed the ability to hinder cell apoptosis induced by CSE. In addition, Rb1 concurrently reduced CSE-induced oxidative reactions and promoted Nrf2 translocation to nucleus. For in vivo study, Rb1 treatment alleviated CSE-induced lung injury, apoptosis, reactive oxygen species (ROS) release and inflammatory reactions. Also, Rb1 treatment activated Nrf2 signaling and inactivated NF-κB signaling in COPD rats.
Conclusion: Rb1 attenuates CSE-induced inflammation, apoptosis and oxidative stress by suppressing NF-κB and activating Nrf2 signaling pathways, which provides novel insights into the mechanism underlying CSE-induced COPD.
Keywords: ginseng saponin Rb1, cigarette smoking exposure, inflammation, oxidative stress, NF-κB, Nrf2