添加丙氨酰谷氨酰胺胃肠外营养对烫伤大鼠的作用
【论文摘要】 目的 探讨添加丙氨酰谷氨酰胺（Ala-Gln）全胃肠外营养（TPN）对烫伤大鼠的空肠黏膜、蛋白质代谢及创面肉芽组织的影响。方法 33只SD大鼠，随机分为非烫伤正常参照组（正常组）、传统TPN组（传统组）和添加Ala-Gln的TPN组（二肽组），每组各11只。正常组自由饮食，另2组大鼠在颈外静脉插管后行30%体表面积Ⅲ度烫伤，并接受等热量（780 kJ·kg-1·d-1）等氮量（1.8 g氮量·kg-1·d-1）TPN 7天，留取24 h尿测每日氮平衡和累积氮平衡；7天后取血测定总蛋白（TP）、白蛋白（ALB）、前白蛋白（PAB）、转铁蛋白（TRF），高效液相法检测肌肉中谷氨酰胺(Gln)的含量；取一段空肠作黏膜形态学观察；光镜下观察烫伤创面肉芽组织的情况。结果 二肽组的血清PAB、TRF及肌肉中Gln含量明显高于传统组（P<0.01），空肠黏膜绒毛高度、隐窝深度、黏膜厚度、绒毛表面积明显高于传统组（P<0.01），创面肉芽组织中的毛细血管和成纤文细胞密度明显高于传统组（P<0.01）。结论 烫伤大鼠应用添加Ala-Gln的胃肠外营养能改善机体氮平衡，促进机体蛋白质合成，http://www.751com.cn减少肌肉中Gln含量的下降，减轻空肠黏膜的萎缩，促进烫伤创面的肉芽增殖愈合。
【论文关键词】 丙氨酰谷氨酰胺；胃肠外营养，全；小肠黏膜；代谢；肉芽组织；烧伤；大鼠
Abstract： Objective To evaluate the effect of alanyl-glutamine (Ala-Gln)-supplemented total parenteral nutrition (TPN) on the intestinal mucosa， protein metabolism and granulation tissues of the wounds in scalded rats. Methods 33 SD rats were randomly divided into three groups (n=11): control group， conventional TPN group (convention group) and Ala-Gln supplemented TPN group (Ala-Gln group). The control group received standard diet， while the two TPN groups having been placed a central venous catheter and subjected to 30% TBSA III0 burn received isocaloric (780kJ·kg-1·d-1) and isonitrogenous (1.8gN·kg-1·d-1， 48% of nitrogen was supplied with Ala-Gln in Ala-Gln group) TPN for 7 days. Nitrogen balance (NB) and cumulated nitrogen balance (CNB) were monitored. At the end of TPN， serum total protein (TP)， albumin (ALB)， prealbumin (PAB)， transferrin (TRF)， Gln in muscle were monitored. Jejunal mucosal morphological changes were observed with light microscopy. The density of capillary vessels and fibroblasts in granulation tissues on wound was observed with light microscopy. Results Serum PAB， TRF， Gln level in muscle and CNB in Ala-Gln groupwere significantly higher than those in the convention group (P< 0.01). The jejunal villus height， crypt depth， mucosal thickness and villous surface area significantly increased in Ala-Gln group. The density of capillary vessels and fibroblasts in the granulation tissues in Ala-Gln group was significantly higher than that in the convention group (P< 0.01). Conclusion Ala-Gln supplemented TPN in scalded rats could promote protein anabolism， improve nitrogen balance， attenuate the decline in Gln in the muscles and attenuate intestinal mucosal atrophy， improve T lymphocyte immune function and promote granulation proliferation and wound healing.
Key words: alanyl-glutamine; parenteral nutrition， total; intestinal mucosa; metabolism; granulation; burns; rats
谷氨酰胺( Glutamine， Gln) 是一种体内含量丰富的游离氨基酸， 它是所有快速增殖细胞的能源物质，如小肠黏膜上皮细胞、淋巴细胞、肿瘤细胞等， 也被认为是应激状态下的“条件必需氨基酸”。烫伤应激状态下，体内蛋白质（尤其是骨骼肌蛋白质）分解和尿氮排泄增加，Gln消耗增加，血浆及组织中Gln浓度下降。补充Gln有可能改善机体氮平衡、促进机体蛋白质合成、减轻小肠黏膜的萎缩。但Gln水溶解度低，且不稳定，在加热灭菌时生成有毒的焦谷氨酸和氨，限制了Gln在肠外营养中的使用，而丙氨酰谷氨酰胺（Ala-Gln）克服了以上缺点，进入体内很快生成Gln。本实验观察了添加Ala-Gln的全胃肠外营养（TPN）对烫伤大鼠的蛋白质代谢、空肠黏膜及烫伤创面的肉芽组织的作用。