Fig. 1.

The cigarette smoke promotes OLK development in the C57BL/6 J mice. The mice were fed water with 4NQO and got cigarette smoke twice a day. All Mice were sacrificed at week 16. a shows histological analysis of oral mucosa epithelial in four groups with hematoxylin and eosin staining. b shows a representative image of the frequency of M2 macrophages (F4/80⁺CD206⁺ cells) from tongue tissue. c shows immunohistochemical analysis of Arg-1 in the oral mucosa epithelial tissue of the mice from the four groups. d Shows the relative mRNA level of Arg-1, IL-10, iNOS, and TNF-α in the tongue tissue of the mice. e shows nicotine and cotinine contents in mice hair of the four groups. Error bars, SEM. *P < 0.05, **P < 0.01, ***P < 0.001