不同营养支持途径对烧伤大鼠肠三叶因子表达的影响

目的探讨不同营养支持途径对烧伤大鼠肠三叶因子（ITF）及其mRNA表达的影响及可能的机制。方法采用30%体表面积Ⅲ度烧伤大鼠模型，随机分成伤前对照（C）组，静脉营养（PN）及肠道营养（EN）组。EN和PN组除营养支持途径不同外，其它条件均相同。在此基础上采用原位杂交、免疫组化和高效液相色谱等手段观察了烧伤后两组大鼠ITF及ITFmRNA的变化。结果正常大鼠小肠中ITF及ITFmRNA均有一定表达，它们主要分布于肠绒毛杯状细胞中。烧伤后PN组大鼠肠道组织结构严重受损，ITFmRNA表达明显降低，肠杯状细胞分泌ITF的能力大幅下降，特别是ITF二聚体的含量远远低于伤前（P＜0.01）。两组比较，EN组大鼠肠组织中ITF及ITFmRNA水平明显高于PN组，同时EN组肠粘膜受损程度也明显低于PN组。结论严重烧伤后肠粘膜结构受损是ITF合成下降的主要原因，肠道营养与静脉营养相比可降低伤后ITF特别是ITF二聚体下降的幅度。

Effects of different nutritional support route on intestinal trefoil factor expression in rats after burn injury

Objective　To explore the mechanisms and effects of different nutritional support route on intestinal trefoil factor (ITF) as well as ITFmRNA expression in burned rats.　Methods　Wistar rats were inflicted with 30% total body surface area full thickness burns and randomly divided into three groups: burned and enteral nutrition (EN), burned and parenteral nutrition (PN), and normal control(C). The expression of ITF mRNA and content of ITF in intestine were quantitatively and localizationally determined with in situ hybridization (ISH), immunohistochemistry and high performance liquid chromatography (HPLC).　Results　ITF and ITF mRNA were expressed in whole small intestine and most of them were localized in goblet cell of intestinal villus. After burn injury, the structure of intestinal mucosa was severely damaged and the ability of goblet cell synthesis ITF, especially ITF dimer, were significantly decreased. EN could lessen the extent of ITF drop though it could not reverse this trend. Meanwhile, as compared with PN, EN could abate intestinal mucosa injury obviously.　Conclusion　It is main reason of the ability of goblet cell synthesis ITF decline that the intestine structure is damaged postburn. As compared with PN, EN can abate the extent of ITF, especially ITF dimer drop.