ABSTRACT
To investigate whether polysaccharides from Enteromorpha prolifera (EPP) could protect against acute hepatic injury induced by CCl4, ICR mice were pretreated with EPP (150, 300, and 450 mg kg-1) and silymarin (100 mg kg-1) for 28 days before CCl4 induction. Pretreatment with EPP attenuated CCl4-induced elevated serum transaminase activities and histopathological alterations in the liver. In addition, EPP prevented CCl4-induced reduction of protein levels of phosphorylated nuclear factor E2-related factor 2 (p-Nrf2)/Nrf2, heme oxygenase-1 (HO-1), and mRNA levels of NADPH quinineoxidoreductase-1 (NQO-1), which, in turn, reduced hepatic oxidative stress injury. Furthermore, the hepatic protein levels of inflammatory mediators and the phosphorylation of nuclear factor-kappaB p65 (NF-κB p65) and I kappaB alpha (IκBα), and the mRNA levels of Toll-like receptor 2 (TLR2), TLR4, and prolyl-isomerase-1 (Pin-1) in the inflammatory signaling pathway were recovered in the EPP pretreated groups. Moreover, EPP prevented the hepatocellular apoptotic changes with inhibition of B-cell lymphoma 2 (Bcl-2), and the induction of Bcl-2-associated X (Bax) and Cleaved caspase-3 caused by CCl4. Taken together, these results indicated that EPP protected against hepatic injury induced by CCl4-derived reactive intermediates through the activation of Nrf2/HO-1 signaling, and suppression of oxidative stress, inflammation and apoptosis.
Subject(s)
Chemical and Drug Induced Liver Injury/prevention & control , Chlorophyta , Polysaccharides/pharmacology , Animals , Apoptosis/drug effects , Carbon Tetrachloride , Disease Models, Animal , Heme Oxygenase-1/metabolism , Inflammation/metabolism , Male , Mice , Mice, Inbred ICR , NF-E2-Related Factor 2/metabolism , Oxidative Stress/drug effects , Polysaccharides/therapeutic use , Random Allocation , Signal Transduction/drug effectsABSTRACT
Non-alcoholic fatty liver disease (NAFLD) is caused by fat accumulation and is associated with abnormal cholesterol metabolism. Previous work indicates that polysaccharides from alga Enteromorpha prolifera improve glucose metabolism and lower cholesterol in diabetic rats. Thus, we studied the possible protective effects of E. prolifera polysaccharides (EP) in the development of NAFLD and underlying mechanisms. EP (200 mg kg-1) significantly reduced the liver weight and significantly lowered hepatic HMG-CoA reductase (HMGCR) mRNA protein expression. EP suppressed sterol regulatory element binding protein-2, which is a key transcription factor in cholesterol metabolism and regulates the expression of HMGCR. Therefore, EP may be a functional food that can prevent NAFLD.