Levosimendan mitigates renal fibrosis via TGF-β1/Smad axis modulation in UUO rats

Chronic kidney disease (CKD) is characterized by kidney fibrosis involving epithelial-mesenchymal transition (EMT), and extracellular matrix (ECM) accumulation, and often leads to end-stage kidney disease (ESKD). Currently, available therapies are not uniformly effective and lead to serious adverse effects. Levosimendan (LVS), a calcium sensitizer and an inodilator, manages cardiac failure. We aimed to evaluate the renoprotective effect of LVS on unilateral ureteral obstruction (UUO)-induced CKD in male Sprague-Dawley (SD) rats and exogenous transforming growth factor-β1 (TGF-β1)-induced fibrosis in NRK-52E cells. Rats were randomly grouped as normal control (NC), sham, UUO and UUO + LVS (3 mg/kg, p.o., o.d.) for 21 days. All animals were sacrificed post-treatment, and plasma, urine and kidney specimens were utilized for biochemistry, histology, immunohistochemistry and immunoblotting. Moreover, exogenous TGF-β1 was used to stimulate kidney fibrosis in NRK-52E cells and treated with LVS (10 µM) for 48 h. The in-vitro samples were collected for cell morphology, viability, immunofluorescence and immunoblotting. LVS treatment significantly improved the kidney mass, plasma and urine creatinine, BUN, urine urea nitrogen and plasma proteins levels of TGF-β1 and fibronectin. Histology revealed a significant decrease in tubular necrosis, glomerulosclerosis and tubulointerstitial fibrosis in LVS-treated rats. Moreover, LVS treatment remarkably downregulated the levels of α-SMA, vimentin, p-Smad 2/3 and upregulated E-cadherin in UUO rats, decreased Smad 4, collagen I, β-catenin, and MMP-7-mediated ECM and increased Smurf 2 and Smad 7 in NRK-52E cells. LVS inhibits EMT and ECM turnover via TGF-β1/Smad axis modulation, highlighting the potential clinical use of LVS for CKD.