Inhibition of Src kinase can ameliorate renal interstitial fibrosis in unilateral ureteral obstruction mice

Objective To investigate the effect and mechanism of Src kinase in renal interstitial fibrosis of unilateral ureteral obstruction (UUO) mice. Methods Male C57BL/6J mice were randomly divided into 4 groups, including sham operation group (n=8), sham operation+PP2 group (n=8), UUO operation group (n=8) and UUO operation+PP2 group (n=8). The mice were injected 2 mg/kg PP2 by intraperitoneal everyday after surgery in sham+PP2 group and UUO+PP2 group. PP2 dissolved in 1% DMSO (formulated with normal saline). Sham and UUO group were given equal 1% DMSO. The mice were sacrificed at 7th day. Renal collagen was observed with Sirius red stain. The activities of Src, protein kinase B (PKB, AKT), p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK) and the protein expressions of α-smooth muscle actin (α-SMA) and fibronectin (FN) were detected by Western blotting. The expression of collagen I (COLⅠ) was detected by immunohistochemistry and the expressions of matrix metalloprotein 9 (MMP-9), tissue inhibitor of metalloproteinase 1 (TIMP-1), transforming growth factor-β1 (TGF-β1), monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6) were measured by ELISA. Results Compared with sham mice, UUO mice on 7th day displayed obvious renal fibrosis. Meanwhile, UUO mice had increased expressions of COLⅠ and FN, and activities of AKT, ERK and p38 MAPK (all P＜0.05). Their renal expressions of α-SMA, TGF-β1, MMP-9, TIMP-1, MCP-1 and IL-6 were also raised (all P＜0.05). Compared with those in UUO group, in UUO+PP2 group the activities of Src, AKT, p38 MAPK and ERK, and expressions of TGF-β1, MCP-1 and IL-6 decreased (all P＜0.05). Additionally, expressions of COLⅠ, FN and α-SMA, collagen deposition and renal fibrosis receded in UUO+PP2 group (all P＜0.05). However, the expressions of MMP-9 and TIMP-1 were not influenced by PP2 treatment. Conclusions Src kinase promotes myofibroblasts accumulation and inflammatory reaction through activating its downstream signaling pathway in the progressing of renal interstitial fibrosis.