Fig. 2.

Long term TS-induced CSC-like properties were associated with IL-33 upregulation. Mice were exposed to TS for 12 weeks, and representative micrographs of liver tissues were stained with H&E (a). The expression of IL-33 was detected by immunohistochemical staining (b). c IL-33 positive areas in TS group relative to FA group. d Western blotting of IL-33 in liver tissues. β-actin was served as the loading control. e Six animal samples per group were used for the densitometric analysis of IL-33 protein. Data are expressed as mean ± SD. The significance was assessed with unpaired two-tailed Student’s t test. ## P < 0.01, compared with FA control. FA = filtered air; TS = tobacco smoke