| Summary: | 博士 === 國立陽明大學 === 傳統醫藥研究所 === 104 === Total parenteral nutrition (TPN) is often complicated by cholestatic hepatitis. The mechanism is unknown till now and no definite therapeutic method is available clinically. Glycyrrhizin, one major constituent of Licorice (Glycyrrhizae radix), has been known to exhibit of anti-infalmmatory, antihepatotoxic, and antioxisative activity. Glycyrrhizin, a major active component, has also not been investigated for its protective effect of glycyrrhizin on choletsasis hepatitis resulting from total parenteral nutrition in detail. The aim of study was to investigate whether glycyrrhizin is able to act as an anti-inflammatory agent using a model of TPN-associated acute liver injury in vivo and the mechanisms involved. Then differential proteomics is used to analyze the differences of protein expression for the research on molecular mechanism and tracing the acute TPN induction liver cytotoxicity. Sprague-Dawley rats were randomized into three groups. A control ground was given saline infusion and the total parenteral nutrition group was administered total parenteral solution for 3 hours and other rats in the glycyrrhizin group were given glycyrrhizin by intravenous administration, killed and assessed for liver pathology examination and bile output amount. We extracted the whole liver tissues and serum proteins, then compared the differences in the protein expressions of TPN and glycyrrhizin treatment. Pathogenesis involved in oxidative stress signaling pathway are measured by histopathological and immunohistochemical examination as well as proteomic approaches. We found that aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TB) and triglyceride (TG) levels were significantly increased in the TPN group without glycyrrhizin pretreatment but decreased in the glycyrrhizin-pretreated TPN group in a dose-dependent manner. The stained liver sections showed that glycyrrhizin relieved acute liver injury. The upregulation of serum protein biomarkers of reactive nitrogen species, including nitrotyrosine and inducible NO synthase (iNOS), were attenuated by glycyrrhizin pretreatment. Levels of endoplasmic reticulum (ER) stress factors, such as phosphorylation of JNK1/2, p38 MAPK and CHOP, were decreased by glycyrrhizin pretreatment. Five proteins that were differentially expressed between TPN infusion and normal rats were determined and validated in vivo. Fascinatingly, the proteomic differential displays identified downregulated proteins included peroxiredoxin 2 (PRDX2), alpha-1-antiproteinase (A1AT), and fibrinogen gamma chain (FIBG), which were involved in oxidative stress, inflammatory respondence and cells apoptosis. After TPN infusion, two protein spots showed increased expression, namely, the glucagon receptor (GLR) protein and apolipoprotein A-1 (APOA1), which may mediate the effects of TPN administration on glycogen and lipid metabolism. Results of these studies showed that glycyrrhizin has protective effects on TPN induced liver injury. These findings provide further insight into the mechanisms through which glycyrrhizin exerts its beneficial effect on the injured livers and suggests glycyrrhizin may be a promising agent for clinic therapy of TPN’s damage. Proteomic analysis suggested TPN-induced acute liver injury could be involved in limiting cellular protection mechanisms against oxidative stress-induced apoptosis, which also give molecular evidences for TPN induced hepatitis
Keywords: glycyrrhizin; total parenteral nutrition; proteomic; oxidative stress; inflammatory response; acute liver injury.
|
|---|
