Abstract
BACKGROUND: Uncontrolled diabetes results in diabetic kidney disease (DKD), impacting approximately 40% of individuals with diabetes. Early indicators include podocyte damage and proteinuria, which are influenced by oxidative stress and dysregulation of the Nrf2/HO-1 pathway. OBJECTIVE: To examine the potential effect of Sacubitril/valsartan (LCZ696) on the oxidative stress of podocytes induced by hyperglycemia via the signaling pathway. METHODS: Podocytes were categorized into four groups: the first group was exposed to a normal glucose level 5.5 mmol/L, the second group to a high glucose at 40 mmol/L, the third group to a high glucose with LCZ696 at a concentration of 10 µM and the fourth group to a high glucose with Valsartan (VAL) at a concentration of 10 µM. Cell viability was evaluated using the CCK-8 assay. The rate of apoptosis in podocytes was determined through flow cytometry with Annexin V-FITC and PI staining. Oxidative stress parameters were assessed using ROS detection kits. To explore the role of Nrf2 signaling, its expression in podocytes was silenced via siRNA transfection, enabling the evaluation of LCZ696's effects on oxidative stress and apoptosis in the absence of Nrf2 signaling. The expression levels of HO-1 and Nrf2 were analyzed through Western blotting and real-time polymerase chain reaction (rtPCR). RESULTS AND DISCUSSION: The Cell viability study results suggested that a 10 µM concentration of LCZ696 showed better effects. LCZ696 at 10 µM significantly enhanced cell viability and reduced apoptosis in podocytes exposed to high glucose levels. Apoptotic markers showed a notable decrease in the HG + LCZ696 group compared to the HG group, highlighting LCZ696's superior efficacy over VAL in preventing glucose-induced cell death. The HG group showed significantly higher levels of ROS and MDA compared to the NG group, whereas the SOD levels were considerably lower. ROS levels in the HG + LCZ696 and HG + VAL groups were considerably lower than those in the HG group. Additionally, oxidative stress markers, such as ROS and MDA, were significantly reduced, while SOD levels were notably increased in the LCZ696 and VAL groups compared to the HG group. The relative protein mRNA expression levels of Nrf2 and HO-1 in the HG + LCZ696 group were significantly higher (P < 0.001) compared to the HG group. Compared to the NG group, the relative expression levels of the Nrf2 and HO-1 were lower in the HG group (P < 0.01) and significantly higher in the HG + LCZ696 group than in the NG group (P < 0.05). Moreover, LCZ696 upregulated Nrf2 and HO-1 protein and gene expression levels, mitigating oxidative stress. siRNA-mediated knockdown of Nrf2 further confirmed that LCZ696's protective effects were Nrf2-dependent, as Nrf2 suppression eliminated LCZ696's antioxidative and anti-apoptotic benefits, underscoring Nrf2's role in LCZ696's mechanism. CONCLUSIONS: LCZ696 can inhibit oxidative stress and improve elevated glucose-induced apoptosis in podocytes via the Nrf2/HO-1 signaling pathway.