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Hemorrhagic shock/resuscitation involves overwhelming reactive oxygen species (ROS) that cause oxidative stress, inflammation, and subsequent tissue injury. We investigated the effects of the potent antioxidant carboxyfullerene (C3) on acute liver injury during hemorrhage shock/resuscitation. C3 infusion reduced the alanine aminotransferase (ALT) activity, methemoglobin content, malondialdehyde content, myeloperoxidase activity and expression levels of tumor necrosis factor -α and interleukin-6; it increased superoxide dismutase activity in the liver. The histologic injury score and apoptotic index were also markedly decreased after C3 treatment compared with the vehicle group. Additionally, C3-treated rats showed a significant decrease in nuclear factor-κB DNA binding capacity, which was preceded by reduced phosphorylation of the nuclear factor κB (NF-κB) p65 subunit in the liver. C3 nanoparticles ameliorate oxidative stress, the inflammatory response, and subsequent acute liver injury after hemorrhagic shock/resuscitation. These protective effects appear to be mediated through the inhibition of the nuclear factor-κB pathway. C3 treatment may be a promising strategy to improve tissue injury in hemorrhagic shock/resuscitation.

Sepsis-associated acute liver injury contributes to the pathogenesis of multiple organ dysfunction syndrome and is associated with increased mortality. Currently, no specific therapeutics for sepsis-associated liver injury are available. With excess levels of reactive oxygen species (ROS) being implicated as key players in sepsis-induced liver injury, we hypothesize that ROS-responsive nanoparticles (NPs) formed via the self-assembly of diblock copolymers of poly(ethylene glycol) (PEG) and poly(propylene sulfide) (PPS) may function as an effective drug delivery system for alleviating sepsis-induced liver injury by preferentially releasing drug molecules at the disease site. However, there are no reports available on the biocompatibility and effect of PEG-b-PPS-NPs in vivo. Herein, this platform was tested for delivering the promising antioxidant therapeutic molecule melatonin (Mel), which currently has limited therapeutic efficacy because of its poor pharmacokinetic properties. The mPEG-b-PPS-NPs efficiently encapsulated Mel using the oil-in-water emulsion technique and provided sustained, on-demand release that was modulated in vitro by the hydrogen peroxide concentration. Animal studies using a mouse model of sepsis-induced acute liver injury revealed that Mel-loaded mPEG-b-PPS-NPs are biocompatible and much more efficacious than an equivalent amount of free drug in attenuating oxidative stress, the inflammatory response, and subsequent liver injury. Accordingly, this work indicates that mPEG-b-PPS-NPs show potential as an ROS-mediated on-demand drug delivery system for improving Mel bioavailability and treating oxidative stress-associated diseases such as sepsis-induced acute liver injury.