Hepatic macrophage M1 polarization was positively correlated with the expression of 17β-HSD7 during NAFLD development. (A–C) Proportion of M1 (F4/80+CD11c+) and M2 (F4/80+CD206+) macrophages in the liver tissues of control and HFD mice fed for 2, 4 and 6 weeks (n = 4). (D) Dynamic changes of M1, M2 and M1/M2 in the liver tissues of control and HFD mice fed for 2, 4 and 6 weeks (n = 4). (E) The relationship between macrophage 17β-HSD7 expression and proportion of M1 (n = 24). Data are expressed as mean ± SD. ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001. 17β-HSD7, 17β-hydroxysteroid dehydrogenase type 7; HFD, high-fat diet; NAFLD, nonalcoholic fatty liver disease.