Figure 8. Melatonin promoted expression of Nrf2/HO-1 pathway and decreased ROS level in vivo. (A–C) The mRNA level of Nrf2, HO-1 and NQO1 was detected by RT-PCR. (D–G) The protein level of Nrf2, HO-1 and NQO1 were detected by Western blot. (H, I) Nrf-2 expression were detected by immunohistochemical staining (magnification ×400). Intima and media were labeled with "I" and "M" respectively. Nrf-2 mean density was analyzed in each group (a, control group; b, smoking group; c, melatonin group). (J, K) Representative images of carotid arteries stained with DHE (red), DAPI (blue) and merge images in (a–c) control, (d–f) smoking, and (g–i) melatonin groups. The fluorescent intensities of ROS were quantified. *p < 0.05, **p < 0.01. The data are represented as mean ± SD (n = 3).