Epithelial-to-Mesenchymal Transdifferentiation of Renal Tubular Epithelial Cell Mediated by Oxidative Stress and Intervention Effect of Probucol in Diabetic Nephropathy Rats

Abstract

Objective: To elucidate the relationship of oxidative stress and specificity protein 1 (Sp1) in the process of epithelial-tomesenchymal transdifferentiation (EMT) and also to investigate the molecular mechanism of protective effect of probucol on the pathogenesis of diabetic kidney disease (DKD). Methods: Thirty male Sprague-Dawley (SD) rats were randomly divided into control group, diabetic group, and diabetic group under probucol therapy (n ¼ 10 per group). The biochemical indicators including 24-h urinary total protein (24-h UTP) excretion, blood glucose (BG), lipids [triglycerides (TGs), total cholesterol (TC)], serum creatinine (Scr), creatinine clearance rate (Ccr), kidney tissue malondialdehyde (MDA) level, and glutathione peroxidase (GSH-Px) activity were assessed in all groups. The renal pathological changes were evaluated by hematoxylin and eosin (HE) and Masson staining. The protein expression of Sp1, α-smooth muscle actin (α-SMA), and Ecadherin was also measured and analyzed by immunohistochemistry and Western blotting. Results: Compared with the control group, the BG, TC, Scr, 24-h UTP, and MDA level of renal tissue increased significantly and the Ccr reduced in the rats of diabetic group (all p < 0.01). The pathological scores and the expression of Sp1 and α-SMA in renal tissue were upregulated (p < 0.01) and the expression of E-cadherin was down-regulated significantly in the diabetic animals (p < 0.01). In the diabetic animals treated with probucol, the renal injuries were alleviated (p < 0.01). Conclusions: Oxidative stress may play an important role in the EMT process of tubular epithelial cells. Probucol could ameliorate renal disease progression in this model of diabetic nephropathy, which might be due to an antioxidant action, down-regulation of Sp1 protein expression, and inhibition of renal tubular EMT.

Probucol ameliorates renal injury in diabetic nephropathy by inhibiting the expression of the redox enzyme p66Shc

“…We therefore surmised that probucol reduces oxidative damage by inhibiting p66Shc expression. Our results also support the findings of previous studies, which suggest that probucol is a cholesterol-lowering drug with antioxidant properties that protect against free radical-induced damage in a wide variety of scenarios, including doxorubicin-induced cardiotoxicity [7], HG-induced podocyte injury [49] and tubular epithelial cell injury [6]. The mechanism by which probucol protects against oxidative injury may involve increase in antioxidant gene mRNA expression and decrease in apoptosis via improving mitochondrial oxidative phosphorylation and energy production [1].…”

“…Along these lines it has been demonstrated that probucol suppresses oxidative stress and attenuates oxidative injury in the renal podocytes of db/db mice by inhibiting NADPH oxidase 2 (Nox2) expression [49]. Conceivably, by virtue of probucol being an antioxidant it has been proposed to inhibit renal tubular epithelial- mesenchymal transition (EMT) in mouse models of DN [6], [31]. However, the molecular mechanism(s) underlying this phenomena are not precisely delineated.…”

Probucol attenuates ethanol-induced liver fibrosis in rats by inhibiting oxidative stress, extracellular matrix protein accumulation and cytokine production

“…In the present study, both mRNA and protein levels of α ‐SMA were increased in Group II compared with Group I. Probucol treatment markedly reduced α ‐SMA expression in rats treated with ethanol + CCl 4 . Interestingly, probucol has also been reported to reduce the upregulation of α ‐SMA in diabetic nephropathy rats . These results indicate that probucol protects against liver fibrosis at least in part by inhibiting HSC activation.…”

Protective effects of leflunomide on renal lesions in a rat model if diabetic nephropathy

“…13 Renal tubular epithelial-myofibroblast transdifferentiation plays a very important role in the development of tubular lesion and tubulointerstitial fibrosis. 14,15 In the diabetic kidney, the extensive infiltration of monocytes/macrophages can cause the accumulation of extracellular matrix, thickening of the glomerular basement membrane, and the subsequent development of interstitial fibrosis and glomerular sclerosis. 16 Studies have shown that diffuse glomerulosclerosis is associated with macrophages infiltration.…”