BACKGROUND: Renal interstitial fibrosis is a major complication of cisplatin (CP) treatment, and increased sodium intake may accelerate its progression by stimulating transforming growth factor (TGF)-β/Smad signaling. However, it is not clear whether a low-sodium diet has beneficial effects on the development of interstitial fibrosis because it activates the renin-angiotensin-aldosterone system. Here, we tested whether the TGF-β/Smad signaling pathway is stimulated in CP-treated rats, and whether the development of tubulointerstitial fibrosis in CP nephropathy can be checked by dietary sodium restriction. METHODS: Male Sprague Dawley rats were randomly divided into controls, CP treatment and CP treatment with low-sodium diet. The acute experiment lasted 7 days with a single intraperitoneal injection (6 mg/kg) of CP, and the chronic experiment involved weekly injections (2 mg/kg) for 7 weeks. RESULTS: In both sets of experiments, CP treatment produced pronounced tubulointerstitial injury, increased infiltration of ED1-positive cells and increased expression of monocyte chemotactic protein-1 (MCP-1), α-smooth muscle actin (SMA), TGF-β1, phosphorylated Smad3, fibronectin and collagen III proteins. In the acute experiment, the increases in expression of osteopontin, MCP-1, α-SMA, TGF-β and collagen III were significantly reduced by dietary sodium restriction. In the chronic experiment, however, none of the measurements were improved by a low-sodium diet. Examination of CP-treated rat kidneys revealed de novo vimentin expression in tubular epithelial cells and invasion of α-SMA-positive tubular epithelial cells through the basement membrane into the interstitium. CONCLUSIONS: The pro-fibrotic effect of TGF-β in CP nephropathy appears to be associated with the epithelial-mesenchymal transition and is ameliorated by dietary sodium restriction only during the acute phase.
BACKGROUND:Renal interstitial fibrosis is a major complication of cisplatin (CP) treatment, and increased sodium intake may accelerate its progression by stimulating transforming growth factor (TGF)-β/Smad signaling. However, it is not clear whether a low-sodium diet has beneficial effects on the development of interstitial fibrosis because it activates the renin-angiotensin-aldosterone system. Here, we tested whether the TGF-β/Smad signaling pathway is stimulated in CP-treated rats, and whether the development of tubulointerstitial fibrosis in CP nephropathy can be checked by dietary sodium restriction. METHODS: Male Sprague Dawley rats were randomly divided into controls, CP treatment and CP treatment with low-sodium diet. The acute experiment lasted 7 days with a single intraperitoneal injection (6 mg/kg) of CP, and the chronic experiment involved weekly injections (2 mg/kg) for 7 weeks. RESULTS: In both sets of experiments, CP treatment produced pronounced tubulointerstitial injury, increased infiltration of ED1-positive cells and increased expression of monocyte chemotactic protein-1 (MCP-1), α-smooth muscle actin (SMA), TGF-β1, phosphorylated Smad3, fibronectin and collagen III proteins. In the acute experiment, the increases in expression of osteopontin, MCP-1, α-SMA, TGF-β and collagen III were significantly reduced by dietary sodium restriction. In the chronic experiment, however, none of the measurements were improved by a low-sodium diet. Examination of CP-treated rat kidneys revealed de novo vimentin expression in tubular epithelial cells and invasion of α-SMA-positive tubular epithelial cells through the basement membrane into the interstitium. CONCLUSIONS: The pro-fibrotic effect of TGF-β in CP nephropathy appears to be associated with the epithelial-mesenchymal transition and is ameliorated by dietary sodium restriction only during the acute phase.
Authors: Wiwit Ananda Wahyu Setyaningsih; Nur Arfian; Efrayim Suryadi; Muhammad Mansyur Romi; Untung Tranggono; Dwi Cahyani Ratna Sari Journal: Iran J Med Sci Date: 2018-03