肠内外免疫营养对重症急性胰腺炎大鼠机体免疫功能的影响

Effect of enteral and parenteral immunonutrition on immune function in rats with severe acute pancreatitis

目的探讨肠内外免疫营养对重症急性胰腺炎(Severe Acute Pancreatitis,SAP)大鼠机体免疫功能的影响,为临床治疗SAP选择最佳营养支持提供理论依据。方法选取清洁级SD雄性大鼠,共48只,随机分为假手术组、模型组、普通肠内营养组、肠内免疫营养组、普通肠外营养组和肠外免疫营养组,每组8只。酶联免疫吸附测定(Enzyme Linked Immunosorbent Assay,ELISA)检测各组大鼠小肠黏液分泌型免疫球蛋白(Secretory Immunoglobulin A,SIgA)含量及白细胞介素10(IL-10)、白细胞介素6(IL-6)表达水平;苏木精-伊红染色法(Hematoxylin-eosin Staining,HE)染色检查胰腺病理学改变;鲎试验法检测各组大鼠血浆内毒素;流式细胞术检测外周血CD4^(+)T、CD8^(+)T、CD4^(+)T/CD8^(+)T;实时荧光定量聚合酶链反应(Polymerase Chain Reaction,PCR)检测各组大鼠紧密连接蛋白分子(Occludin mRNA)表达水平。结果与假手术组相比,模型组大鼠血浆内毒素含量、IL-6表达水平均显著升高而小肠黏液SIgA含量、CD4^(+)T、CD4^(+)T/CD8^(+)T、IL-10表达水平及occludin mRNA表达水平均显著降低(P均<0.05);与模型组相比,各治疗组大鼠各指标均有不同程度改善(P均<0.05);与普通肠内营养组和普通肠外营养组相比,肠内免疫营养组和肠外免疫营养组内毒素含量、IL-6表达水平均显著降低而小肠黏液SIgA含量、CD4^(+)T、CD4^(+)T/CD8^(+)T、IL-10表达水平及occludin mRNA表达水平均显著升高(P均<0.05);与肠外免疫营养组相比,肠内免疫营养组各指标改善更为显著。结论SAP大鼠小肠黏膜紧密连接蛋白(Occludin)表达降低导致内毒素等从肠腔中进入血液,破坏大鼠免疫功能,体内炎症水平升高,导致肠组织损伤;肠内外免疫营养支持均可显著改善SAP,但肠内免疫营养支持在提升SAP大鼠免疫机能和改善免疫状态方面效果优于肠外营养。

Objective To investigate the effect of enteral and parenteral immunonutrition on the immune function in rats with Severe Acute Pancreatitis(SAP),and to provide a theoretical basis for selecting the best nutritional support for the clinical treatment of SAP.Methods A total of 48 clean SD male rats were randomly divided into the sham operation group,model group,ordinary enteral nutrition group,enteral immunonutrition group,ordinary parenteral nutrition group,and parenteral immunonutrition group,with eight rats in each group.The content of Secretory Immunoglobulin A(sIgA)and the expression levels of Interleukin-10(IL-10)and Interleukin-6(IL-6)were measured by Enzyme-Linked Immunosorbent Assay(ELISA);The pathological changes of the pancreas were examined by Hematoxylin-eosin Staining(HE);The plasma endotoxin was detected by Tachypleus Amebocyte Lysate test;The CD4+T,CD8+T,and CD4+T/CD8+T lymphocytes in peripheral blood were detected by flow cytometry;The expression level of the tight junction protein(occludin mRNA)was detected by real-time fluorescence quantitative Polymerase Chain Reaction(PCR).Results Compared with the sham operation group,the content of plasma endotoxin and the expression level of IL-6 in the model group were significantly higher,while the content of SIgA,CD4+T,CD4+T/CD8+T lymphocytes,and the expression level of IL-10 and occludin mRNA in small intestinal mucus were significantly lower(P<0.05);Compared with the model group,the indexes of rats in all treatment groups were improved in various degrees(all P<0.05);Compared with the general enteral nutrition group and the general parenteral nutrition group,the content of endotoxin and the expression level of IL-6 in the enteral immunonutrition group and the parenteral immunonutrition group were significantly lower,while the content of SIgA,CD4+T,CD4+T/CD8+T lymphocytes,and the expression level of IL-10 and occludin mRNA in the small intestinal mucus were significantly higher(all P<0.05);Compared with parenteral immunonutrition group,the indexes of enteral immunonutrition group improved more significantly.Conclusion The decreased expression level of tight junction protein(occludin)in the small intestinal mucosal of rats leads to endotoxin entering the blood from the intestinal cavity,damaging the immune function,increasing the level of inflammation in vivo,and resulting in intestinal tissue damage;The enteral and parenteral immunonutrition support could both improve SAP significantly,while the former outperforms the latter in improving the immune function and immune state of SAP rats.