TNF and chronic obstructive pulmonary disease: As shown in Figure 2, in agreement with the histological inflammatory changes, a memorably higher level of IL-6 (Figure 2A), TNF-α (Figure 2B), IL-17A (Figure 2C), IL-4 (Figure 2D), and IFN-γ (Figure 2E) was observed in COPD mice (p < 0.01), while they were significantly decreased with PLE treatment (p < 0.05 or 0.01), showing a dose-dependent manner in the decrease of IL-6, TNF-α, and IL-4.