To observe the impact of transforming growth factor (TGF-β1) on bone marrow-derived macrophages (BMDM), and explore whether Wnt signaling could play a regulative role in the process of fibrosis or not.

Mouse BMDM was obtained by aseptic isolation, and colony stimulating factor (M-CSF) was used as a stimulating factor. The cells were cultured in a 5% CO₂ incubator for 7 days at 37 ℃. The morphology of the cells was observed by inverted phase contrast microscope. The purity of BMDM was identified by flow cytometry. TGF-β1 was used as an intervention factor to establish a control group (group A: high glucose complete medium+ M-CSF) and an experimental group (group B: high glucose complete medium+ M-CSF+ TGF-β1), with the M-CSF concentration of 60 ng/ml and the TGF-β1 concentration of 5 ng/ml. α-SMA was used as a surface marker of myofibroblasts, and F4/80 was used as a surface marker of macrophages. After 3 days, the ratio of α-SMA⁺ F4/80⁺ cells was detected by flow cytometry, and expression of Wnt3a, disheveled protein (DVL), and β-catenin of each group was determined by Western blot. Data processing was performed with SPSS19.0 statistical software.

After 7 days of M-CSF stimulation, the ratio of BMDM was the highest by flow cytometry, and the purity was (94.44±6.11)%. Compared with the control group, after 3 days, the ratio of α-SMA⁺ F4/80⁺ cells was significantly increased (t=6.365, P=0.0007), and the protein expression of Wnt3a, DVL, and β-catenin was also significantly increased (t_Wnt3a=12.06, P<0.0001; t_DVL=8.168, P=0.0002, t_β-catenin=6.752, P=0.0005) in the experimental group.

TGF-β1 could stimulate the transformation of BMDM into myofibroblasts. Wnt signaling pathway might be involved in the regulation of BMDM fibrosis. Decreasing the activity of Wnt signaling pathway in macrophages might be a potential therapeutic approach to delaying fibrosis.