谷氨酰胺双肽在肠外营养时调节谷胱甘肽代谢、保护肝脏的机制

Alanyl-glutamine Dipeptiven Protected the Liver Function by Increasing the Hepatic Glutathione

目的谷胱甘肽是机体内保护组织细胞免受自由基损伤的一种主要抗氧化剂,谷氨酰胺是合成谷胱甘肽所必需的前体物质。本实验拟研究丙氨酰谷氨酰胺双肽对支持谷胱甘肽生物合成、保护肝功能的影响。方法 20只Wistar大鼠随机分为标准肠外营养对照组(STD)及丙氨酰谷氨酰胺双肽强化的肠外营养(ALA-GLN)研究组,于腹腔注射5-氟脲嘧啶后,采集并测定血浆及肝脏标本。结果研究组大鼠的血浆谷氨酰胺水平、肝脏还原型谷胱甘肽含量均明显高于对照组,分别为(687.3±49.8)vs(504.9±38.6)μmol/L(P<0.05)和(6.86±2.46)vs(4.38±1.63)μmol/g肝组织(P<0.05)。研究组肝脏酶学变化指标明显低于对照组(P<0.05)。结论谷氨酰胺双肽在肠外营养时能够通过调节谷胱甘肽的合成代谢,增加其在肝脏的贮存而保护肝脏功能。

Glutathione (GSH) is a major antioxidant which protects hepatic tissues from free radical injury. Alanyl-Glutamine (ALA-GLN) proved to be a precursor of GSH synthesis, was used to investigate the relationship to GSH biosynthesis which may be effective for hepatic protection. Methods 20 male Wistar rats were randomly divided into two groups receiving standard parenteral nutrition (STD) supplemented with or without ALAGLN for 7 days. At 5th day 5-fluorouracil (5-FU) was injected peritoneally, the blood samples for GSH, GSSG, ALT (sGPT), AKP and TBilli tests were measured after 4-8 h. Resuits The concentration measurments were significantly different in ALA-GLN group compared with STD animals in serum GLN (687. 3±49.8) vs (504.9±-38.6) μmol/L, P<0.05), serum GSH (14.37±5.16) vs (7.08±3.16) μmol/L, P<0.01) and in liver GSH content (6.86±2.46) vs (4.38±1.63) μmol/g liver tissue, P<0.05). Rats in ALA-GLN group have lesser elevations in hepatic enzymes after 5-FU administration. Conclusions The supplemented nutrition ALA-GLN protected the liver function through increasing the glutathione biosynthesis and preserving the glutathione stores of hepatic tissue.