Nephroprotective effect of Ginsenoside Rg1 in lipopolysaccharide-induced sepsis in mice through the SIRT1/NF-κB signaling

Abstract

Introduction. During sepsis, the kidney is one of the most vulnerable organs. Sepsis-associated acute kidney injury (S-AKI) is hallmarked by renal inflammation, apoptosis, and oxidative injury. Ginsenoside Rg1 (Rg1) is a natural product that possesses abundant pharmacological actions and protects against many sepsis-related diseases. Nevertheless, its role and related mechanism in S-AKI remain to be determined.

Materials and methods. S-AKI was induced using lipopolysaccharide (LPS, 10 mg/kg) via a single intraperitoneal injection. Rg1 (200 mg/kg) was intraperitoneally administered for 3 consecutive days before LPS treatment. For histopathological examination, murine kidney tissues were stained with hematoxylin and eosin. Tubular injury score was calculated to evaluate kidney injury. Serum creatinine and BUN levels were measured for assessing renal dysfunction. The levels and activities of oxidative stress markers (MDA, 4-HNE, PC, GSH, SOD, and CAT) in renal tissue were measured by corresponding kits. Renal cell apoptosis was detected by TUNEL staining. The protein levels of apoptosis-related markers (Bcl-2, Bax, and Cleaved caspase-3), proinflammatory factors, SIRT1, IκBα, p-NF-κB p65, and NF-κB p65 in kidneys were determined using western blotting. Immunofluorescence staining was employed to assess p-NF-κB p65 expression in renal tissues.

Results. LPS-induced injury of kidneys and renal dysfunction in mice were ameliorated by Rg1. Rg1 also impeded LPS-evoked renal cell apoptosis in kidneys. Moreover, Rg1 attenuated LPS-triggered inflammation and oxidative stress in kidneys by inhibiting proinflammatory cytokine release, enhancing antioxidant levels and activities, and reducing lipid peroxidation. However, all these protective effects of Rg1 in LPS-induced AKI mice were reversed by EX527, an inhibitor of sirtuin 1 (SIRT1). Mechanistically, Rg1 upregulated SIRT1 protein expression, increased SIRT1 activity, and inactivated NF-κB signaling in the kidney of LPS-induced AKI mice, which was also reversed by EX527.

Conclusions. Rg1 ameliorates LPS-induced kidney injury and suppresses renal inflammation, apoptosis, and oxidative
stress in mice via regulating the SIRT1/NF-κB signaling.