Ameliorative effects and mechanisms of salvianic acid A on retinal iron overload in vivo and in vitro

Abstract

Excessive iron can be accumulated in the retina and lead to retinal iron overload. Salvianic acid A (SAA) has a variety of pharmacologic effects, but there is only a limited understanding of its benefits for retinal iron overload. The aim of this study was to examine the protective effects and latent mechanisms of SAA on retinal iron overload. SAA reduced iron in the serum and retina, attenuated pathophysiological changes, and reduced retinal iron deposition in the retinas of iron-overloaded mice. It also reduced intracellular iron in ARPE-19 cells by regulating iron-handling proteins and chelating with iron. It also significantly inhibited cellular oxidative and inflammatory damage by increasing the nuclear translocation of nuclear erythroid 2-related factor 2 (Nrf2) while decreasing nuclear factor-kappa B (NF-κB), protecting the ARPE-19 cells from apoptosis by suppressing the Bax/Bcl-2 ratio, cytochrome c release, caspase activation, and poly ADP-ribose polymerase cleavage. The ability of SAA to inhibit apoptosis, increase nuclear Nrf2 expression, and decrease nuclear NF-κB expression was further confirmed in the retinas of iron-overloaded mice. This study demonstrates that SAA shows significant protective effects against retinal iron overload; its mechanisms might be associated with iron chelation; regulation of iron-handling proteins; and inhibition of oxidative stress, inflammation and apoptosis.