In vivo significant increases of TLR4 (Figure 4A), Syk (Figure 4B), p-Syk (Figure 4C), PKC (Figure 4D), p-PKC (Figure 4E), NF-κB p65 (Figure 4F), and p-NF-κB p65 (Figure 4G) expressions were observed in lung tissues of LPS/CS-induced COPD mice (p < 0.05 or <0.01), while all of these increases were notably suppressed with PLE treatment (p < 0.05 or <0.01), acting dose dependently except that of the NF-κB p65 expression. Here, TLR4 is linked to chronic obstructive pulmonary disease.