PEG-SOD attenuates the mitogenic ERK1/2 signaling cascade induced by cyclosporin A in the liver and kidney of albino mice

The calcineurin inhibitor, cyclosporin A (CsA) is one of the most common immunosuppressive agents used in organ transplantation. However, its clinical use is often limited by several unwanted effects including nephrotoxicity and hepatotoxicity. By using immunohistochemical and ELISA techniques, it was found that CsA administration causes a rapid activation of a disintegrin and metalloproteases-17 (ADAM-17), epidermal growth factor receptor (EGFR) and subsequent ERK1/2 phosphorylation in the liver and kidney of albino mice. Furthermore, this study presents mechanistic relevance of this signaling cascade involving reactive oxygen species (ROS)-mediated ADAM-17/EGFR/ERK1/2 activation as indicated by a clear reduction in ADAM-17 and EGFR activities as well as ERK1/2 phosphorylation when the animals pretreated with Polyethylene glycol-superoxide dismutase (PEG-SOD) before CsA administration. Collectively, our findings demonstrate that CsA has the ability to activate ADAM-17-mediated EGFR/ERK1/2 phosphorylation in the liver and kidney of albino mice in ROS-dependent manner. Finally, these data may support the concept of using antioxidant therapy as a valuable approach for the prevention of CsA-induced nephrotoxicity and hepatotoxicity.

Stem cell intervention ameliorates epigallocatechin-3-gallate/lipopolysaccharide-induced hepatotoxicity in mice

Stem cells are identified as a novel cell therapy for regenerative medicine because of their ability to differentiate into many functional cell types. We have shown earlier a new model of hepatotoxicity in mice by administering (1500 mg/kg) epigallocatechin-3-gallate (EGCG) intragastric (IG) for 5 days after a single intraperitoneal dose (6 mg/kg) of lipopolysaccharide (LPS). In this study, we aimed to study the effect of intrahepatic (IH) injection of mouse embryonic stem cells (MESCs) on the hepatotoxicity induced by EGCG/LPS in mice. Mice were administered EGCG/LPS and rested for 3 days. MESCs were obtained from American Type Culture Collection and cultured in vitro for 4 days. Stem cells were injected IH. Seven days later, a single dose of LPS (6 mg/kg) followed by daily doses of IG administration of EGCG were re-administered for 5 days. At the end of the experiment, blood samples were collected for analysis of biochemical parameters associated with liver. Results showed that the group of mice that were administered MESCs prior to EGCG/LPS showed lower levels of alanine amino transferase, alkaline phosphatase, and bilirubin, higher albumin/globulin ratio, and less remarkable histopathological lesions. Also, that group of mice showed less expression of oxidative stress biomarkers (oxidized low-density lipoprotein Ox.LDL and chemokine CXCL16), less expression of nuclear protein receptors (retinoic acid receptor and retinoid X receptor), and less expression of inflammatory biomarkers (tumor necrosis factor α and transforming growth factor β1) compared with other groups of mice that were not given MESCs. In conclusion, MESCs can ameliorate EGCG/LPS-induced hepatotoxicity in mice.