Food and Nutrition Division, School of Biological Sciences, The University of Hong Kong, Hong Kong, SAR, China.
Chin Med. 2012 Oct 18;7(1):23. doi: 10.1186/1749-8546-7-23.
The hepatoprotective potential of Phellinus linteus polysaccharide (PLP) extracts has been described. However, the molecular mechanism of PLP for the inhibition of liver fibrosis is unclear. This study aims to investigate the molecular protein signatures involved in the hepatoprotective mechanisms of PLP via a proteomics approach using a thioacetamide (TAA)-induced liver fibrosis rat model.
Male Sprague-Dawley rats were divided into three groups of six as follows: Normal group; TAA group, in which rats received TAA only; and PLP group, in which rats received PLP and TAA. Liver fibrosis was induced in the rats by repeated intraperitoneal injections of TAA at a dose of 200 mg/kg body weight twice a week for 4 weeks. PLP was given orally at a dose of 50 mg/kg body weight twice a day from the beginning of the TAA treatment until the end of the experiment. The development of liver cirrhosis was verified by histological examination. Liver proteomes were established by two-dimensional gel electrophoresis. Proteins with significantly altered expression levels were identified by matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry and the differentially expressed proteins were validated by immunohistochemical staining and reverse transcription polymerase chain reaction.
Histological staining showed a remarkable reduction in liver fibrosis in the rats with PLP treatment. A total of 13 differentially expressed proteins including actin, tubulin alpha-1C chain, preprohaptoglobin, hemopexin, galectin-5, glutathione S-transferase alpha-4 (GSTA4), branched chain keto acid dehydrogenase hterotetrameric E1 subunit alpha (BCKDHA), glutathione S-transferase mu (GSTmu); glyceraldehyde-3-phosphate dehydrogenase (GAPDH); thiosulfate sulfurtransferase (TFT); betaine-homocysteine S-methyltransferase 1 (BHMT1); quinoid dihydropteridine reductase (QDPR); ribonuclease UK114 were observed between the TAA and PLP groups. These proteins are involved in oxidative stress, heme and iron metabolism, cysteine metabolism, and branched-chain amino acid catabolism.
The proteomics data indicate that P. linteus may be protective against TAA-induced liver fibrosis via regulation of oxidative stress pathways, heat shock pathways, and metabolic pathways for amino acids and nucleic acids.
云芝多糖（PLP）提取物具有保肝作用。然而，PLP 抑制肝纤维化的分子机制尚不清楚。本研究旨在采用硫代乙酰胺（TAA）诱导的肝纤维化大鼠模型，通过蛋白质组学方法研究 PLP 抑制肝纤维化的分子蛋白特征。
雄性 Sprague-Dawley 大鼠分为 3 组，每组 6 只：正常组；TAA 组，大鼠仅接受 TAA；PLP 组，大鼠接受 TAA 和 PLP。每周两次腹腔注射 TAA（剂量为 200mg/kg 体重），连续 4 周诱导肝纤维化。PLP 组从 TAA 治疗开始至实验结束，每天两次给予 50mg/kg 体重的 PLP 灌胃。通过组织学检查验证肝硬化的发展。采用二维凝胶电泳建立肝蛋白质组。采用基质辅助激光解吸电离飞行时间/飞行时间质谱分析鉴定表达水平显著改变的蛋白质，并通过免疫组织化学染色和逆转录聚合酶链反应验证差异表达蛋白。
组织学染色显示 PLP 治疗组大鼠肝纤维化明显减少。在 TAA 和 PLP 组之间观察到 13 种差异表达蛋白，包括肌动蛋白、微管蛋白α-1C 链、前血纤蛋白原、血红素结合蛋白、半乳糖凝集素-5、谷胱甘肽 S-转移酶α-4（GSTA4）、分支链酮酸脱氢酶 hterotetrameric E1 亚基α（BCKDHA）、谷胱甘肽 S-转移酶 mu（GSTmu）；甘油醛-3-磷酸脱氢酶（GAPDH）；硫代硫酸盐硫转移酶（TFT）；甜菜碱-同型半胱氨酸 S-甲基转移酶 1（BHMT1）；醌二氢嘧啶还原酶（QDPR）；核糖核酸酶 UK114。这些蛋白参与氧化应激、血红素和铁代谢、半胱氨酸代谢以及支链氨基酸分解代谢。
蛋白质组学数据表明，云芝可能通过调节氧化应激途径、热休克途径以及氨基酸和核酸代谢途径，对 TAA 诱导的肝纤维化具有保护作用。
