Hydrogen rich water attenuates renal injury and fibrosis by regulation transforming growth factor-β induced Sirt1

The current research was designed to study the role of hydrogen in renal fibrosis and the renal epithelial to mesenchymal transition (EMT) induced by transforming growth factor-β1 (TGF-β1). Hydrogen rich water (HW) was used to treat animal and cell models. Unilateral ureteral obstruction (UUO) was performed on Balb/c mice to create a model of renal fibrosis. Human kidney proximal tubular epithelial cells (HK-2 cells) were treated with TGF-β1 for 36 h to induce EMT. Serum creatinine (Scr) and blood urea nitrogen (BUN) were measured to test renal function, in addition, kidney histology and immunohistochemical staining of alpha-smooth muscle actin (α-SMA) positive cells was performed to examine the morphological changes. The treatment with UUO induced a robust fibrosis of renal interstitium, shrink of glomerulus and partial fracture of basement membrane. Renal function was also impaired in the experimental group with UUO, with an increase of Scr and BUN in serum. After that, Western-blot was performed to examine the expression of α-SMA, fibronectin, E-cadherin, Smad2 and Sirtuin-1 (Sirt1). The treatment with HW attenuated the development of fibrosis and deterioration of renal function in UUO model. In HK-2 cells, the pretreatment of HW abolished EMT induced by TGF-β1. The down-regulation the expression of Sirt1 induced by TGF-β1 which was dampened by the treatment with HW. Sirtinol, a Sirt1 inhibitor, reversed the effect of HW on EMT induced by TGF-β1. HW can inhibit the development of fibrosis in kidney and prevents HK-2 cells from undergoing EMT which is mediated through Sirt1, a downstream molecule of TGF-β1.