Ellagic acid ameliorates aging-induced renal oxidative damage through upregulating SIRT1 and NRF2.

Background: Aging is associated with impaired renal function and structural alterations. Oxidative stress plays a vital role in renal senescence and damage. Sirtuin 1 (SIRT1) is thought to protect cells from oxidative stress through nuclear factor erythroid 2-related factor 2 (NRF2). Ellagic acid (EA), a natural antioxidant, has been demonstrated to have renoprotective roles in vitro and in vivo. This study investigated if SIRT1 and NRF2 mediate the protective effects of EA in aged kidneys.

Methods: Male Wistar rats were divided into three groups including young (4 months), old, and old + EA (25 months). Young and old groups received EA solvent, while the old + EA group was treated with EA (30 mg/kg) by gavage for 30 days. Then, the level of renal oxidative stress, SIRT1 and NRF2 expression, kidney function parameters, and histopathological indices were measured.

Results: Treatment with EA significantly increased the level of antioxidant enzymes and reduced malondialdehyde concentration (P < 0.01). Moreover, EA administration remarkably upregulated mRNA and protein levels of SIRT1 and NRF2 as well as deacetylated NRF2 protein (P < 0.05). Additionally, EA treated rats improved kidney function and histopathological scores (P < 0.05).

Conclusions: These findings suggest that ellagic acid exerts protective effects on aged kidneys by activating SIRT1 and NRF2 signaling.