Magnesium Lithospermate B from Salvia miltiorrhiza Bunge Ameliorates Aging‐Induced Renal Inflammation and Senescence via NADPH Oxidase‐Mediated Reactive Oxygen Generation

The present study was conducted to examine whether magnesium lithospermate B (MLB) extracted from Salviae miltiorrhizae radix was renoprotective in pathways related to age‐related oxidative stress in aged rats. Magnesium lithospermate B was orally administered at a dose of 2‐ or 8‐mg/kg body weight for 16 consecutive days, and the effects were compared with those of vehicle in old and young rats. Magnesium lithospermate B administration to old rats ameliorated renal oxidative stress through reduction of reactive oxygen species. The old rats exhibited a dysregulation of the expression of proteins related to oxidative stress and inflammation in the kidneys, and MLB administration significantly reduced the protein expression of major subunits of nicotinamide adenine dinucleotide phosphate oxidase (Nox4 and p22phox), phospho‐p38, nuclear factor‐kappa B p65, cyclooxygenase‐2, and inducible nitric oxide synthase. In addition, MLB‐treated old rats showed lower levels of senescence‐related proteins such as p16, ADP‐ribosylation factor 6, p53, and p21 through effects on the mitogen‐activated protein kinase pathway. Magnesium lithospermate B administration also significantly attenuated the age‐related increase in serum urea nitrogen, reflecting renal dysfunction, up‐regulated podocyte structural proteins, and reduced renal structural injury. Our results provide important evidence that MLB reduces the renal damage of oxidative stress in old rats. Copyright © 2017 John Wiley & Sons, Ltd.