HMOX1 and chronic obstructive pulmonary disease: In order to further verify that the antioxidation, anti-inflammatory, and antifibrosis effects of RRL on COPD model rats, we examined the expression of related proteins in lung tissue, and the results showed that the RRL could inhibit the upregulation of Ras, p-Raf, p-ERK1/2, Bax, TGF-β1, Smad3, NF-κB p65, and p-IκBα together with downregulation of Bcl-2 Nrf2 and HO-1.