Abstract: Objective To observe the change of expression of WNT4/β-catenin signaling pathway and its inhibitory factor Secreted frizzled-related protein 1 (SFRP1) in renal tissue in diabetic nephropathy（DN） rats, and to explore its possible role in the development of renal fibrosis. Methods Rats were randomly divided into normal control (NC) group and DN group, and was equipped with 8 in each group. The IDDM model was prepared by tail vein injection of STZ 55 mg/kg. Hemotoxyin and eosin、Periodic Acid-Schiff and Masson stain was used to observe the morphological structure and fibrotic lesions in renal tissue; Immunohistochemical analysis was used to observe the protein expression of WNT4 and β-catenin in renal tissue; Western blot was used to detect the protein expression changes of WNT4, SFRP1, β-catenin , p-GSK-3β, GSK-3β, CollagenⅠ, α-SMA, E-cadherin in renal tissue in each group; The mRNA expressions of WNT4 and SFRP1 in renal tissues of rats were detected by real-time PCR. Results Compared with NC group, renal tissue fibrosis was obvious in DN group. Compared with NC group,The protein and mRNA expressions of WNT4 significantly increased (p<0.05), and the protein expressions of β-catenin, p-GSK-3β, α-SMA and CollagenⅠsignificantly increased (p<0.05), and the protein expressions of E-cadherin significantly decreased (p<0.05), and the protein and mRNA expressions of SFRP1 significantly decreased (p<0.05). Conclusions In the case of DN, the signal pathway of WNT4/β-catenin was abnormal activation. The expression of SFRP1 is decreased that may inhibit this pathway and promote the development of renal fibrosis in DN.

Key words: SD rat, Diabetic nephropathy, WNT4, β-catenin, SFRP1