TNF and chronic obstructive pulmonary disease: Accumulated data indicate that Nrf2‐null cells possess lower GSH levels and higher ROS burdens than their equivalent wild‐type cells.46 During the development of COPD, ERK activation produces proinflammatory cytokines, such as TNF‐α, IL‐1β, and IL‐6, which aggravate airway inflammation and destroy the normal alveolar structure.47, 48Our study showed that RLD treatment can downregulate the p‐ERK protein expression.