不同营养支持途径给予谷氨酰胺对烧伤大鼠肠黏膜屏障功能的影响

目的观察不同营养支持途径给予谷氨酰胺(G ln)对严重烧伤所致肠黏膜屏障功能损害的影响并探讨其机制。方法采用30%总体表面积Ⅲ度烧伤大鼠模型,160只W istar大鼠按随机数字表法分成正常对照(C)组、烧伤对照(B)组、G ln静脉营养组〔采用肠外营养(PN)+G ln〕和G ln肠道营养组〔采用肠内营养(EN)+G ln〕。各组烧伤大鼠采用等氮、等热量的营养支持,EN+G ln组给予1.0 g.kg-1.-d 1G ln;PN+G ln组给予等量谷氨酰胺双肽;B组使用等量酪氨酸。观察烧伤后1、3、5、7和10 d肠黏膜屏障功能的变化及不同营养支持途径给予G ln对其的影响。结果烧伤后肠黏膜损伤指数、通透性及血浆二胺氧化酶(DAO)活性均明显高于C组(P均<0.01),而肠黏膜血流量、肠黏膜厚度、绒毛高度、隐窝深度及肠上皮细胞增殖指数则明显降低(P<0.05或P<0.01)。与B组比较,PN+G ln组和EN+G ln组对上述指标的改变均有一定的逆转作用,与PN+G ln组比较,EN+G ln组的疗效更优。结论经肠道补充G ln更有利于减轻烧伤后肠黏膜受损程度,促进肠黏膜修复。

Effects of glutamine given through different avenues on intestine mucosal barrier function in burned rats

OBJECTIVE: To observe the effect of glutamine given through different avenues on intestine mucosal barrier damage induced by severe burn injury. METHODS: One hundred and sixty Wistar rats were randomly divided into four groups: namely normal control (C group), burned control (B group), parenteral nutrition with glutamine (PN+GLN group) and enteral nutrition with glutamine (EN+GLN group). Rats in B group, PN+GLN group, and EN+GLN group were subjected to 30% total body surface area (TBSA) full-thickness burn injury. In the latter three groups, nutritional intake was isonitrogenous and isocaloric. In PN+GLN group and EN+GLN group the nutrition were supplemented with glutamine 1.0 g.kg(-1).d(-1), and in B group tyrosine 1.0 g.kg(-1).d(-1). Indexes relevant to injury to the intestine were determined on postburn day (PBD) 1, 3, 5, 7 and 10. RESULTS: After burn injury, the index of intestinal mucosal injury, intestine mucosal permeability and the activity of plasma diamine oxidase (DAO) were significant increased compared with C group (all P<0.01). On the other hand, the intestine mucosal blood flow (IMBF), mucosa thickness, villous height, crypt depth and intestinal epithelial proliferation index were significantly decreased (P<0.05 or P<0.01). Compared with B group, the extent of changes in these indices were lowered in PN+GLN group and EN+GLN group (P<0.05 or P<0.01), and the effects were more marked in EN+GLN group than those in PN+GLN group. CONCLUSION: GLN is beneficial in minimizing intestinal injury, promoting intestinal mucosal repair. Enteral supplementation of GLN is a better way of administration.