肠内肠外营养对大鼠肠道损伤后屏障功能恢复的实验研究

目的 比较肠内、肠外两种营养支持途径及不同营养物质对胃肠手术后大鼠肠屏障功能的恢复情况.方法 将40只雄性SD大鼠随机分为4组:空白对照组(C组)、肠外营养组(PN组)、普通肠内营养组(EN组)、富含谷氨酰胺的肠内营养组(G-EN组).PN组、EN组、G-EN组行盲肠切除+胃造口置管手术并联合使用阿莫西林50 mg+甲硝唑20 g两次进行干预.术后第1天起各组等氮等热卡连续给予营养支持7 d,于末段回肠5 cm处取肠段1 cm,在光镜下观察肠黏膜形态;采用酶联免疫吸附实验(ELISA)比较血浆D-乳酸含量,检测肠道黏膜通透性;双抗体夹心ABC-ELISA法检测肿瘤坏死因子水平(TNF-α);免疫组化法观察肠黏膜occludin蛋白表达.结果 PN组肠黏膜明显萎缩,其绒毛高度、黏膜厚度、隐窝深度、绒毛表面积及肠黏膜occludin蛋白表达均显著低于C组、EN组、G-EN组(P<0.05),D-乳酸及TNF-α水平显著高于C组、EN组、G-EN组(P<0.05);EN组肠黏膜萎缩较明显,其肠黏膜形态及肠黏膜occludin蛋白表达均低 于C组、G-EN组(P<0.05),D-乳酸及TNF-α水平显著高于C组及G-EN组(P<0.05);G-EN组肠道形态、肠黏膜occludin蛋白表达、D-乳酸及TNF-α水平与C组无统计学差异(P>0.05).结论 谷氨酰胺强化的肠内营养在维护肠黏膜屏障功能、减轻炎症反应,增加肠上皮occludin蛋白表达等方面优于单独使用肠内营养液或肠外营养液,更有助于胃肠手术后大鼠肠屏障功能的恢复.

Research on effects of enteral nutrition and parenteral nutrition on gut mucosal barrier function recovery

Objective To investigate the effect of enteral nutrition(EN)and parenteral nutrition(PN)on gut mucosal barrier function after gastrointestinal surgery.Methods Forty male Sprague Dawley(SD)rats were randomly divided into four groups:Control(C),PN group,EN group,the conventional alanyl-glutamine-enriched enteral nutrition(G-EN)group.PN Group,EN Group and G-EN Group received cecectomy and gastrostomy with the use of 50 mg amoxicillin and 20 mg metronidazole twice.Each group would be treated with isocaloric and isonitrogenous nutrition for next 7 days after the operation,respectively.Taking 5 cm terminal ileum and 1 cm intestines,the morphology of intestinal epithelial tight junctions can be observed by optical microscopy.For each group,then solid-phase sandwich enzyme-linked immunosorbent assay(ELISA)was used to compare levels of plasma D-lactate,and test intestinal mucosal permeability and the serum concentrations of TNF-α was detected by utilizing ELISA.The transmembrane binding proteins(occludin)were measured with immunohistochemistry.Results For PN Group,intestinal mucosa obviously atrophied and the villus height,crypt depth,mucosal thickness,villus surface area of ileum and transmembrane binding proteins(occludin)were lower than those of rats of C Croup,EN Group and G-EN Group(P<0.05),but D-lactate and level of TNF-α were much higher than other groups′(P<0.05).For EN Group,intestinal mucosa atrophied,and the villus height,crypt depth,mucosal thickness,villus surface area of ileum and transmembrane binding proteins(occludin)were lower than those of rats of C Group,G-EN Group(P<0.05),however,D-lactate and level of TNF-α were much higher than C and G-EN Groups′(P<0.05).There was no significant difference between G-EN Group and C Group in the ileal membrane morphology transmembrane binding proteins(occludin)expression level,intestinal mucosa permeability and level of TNF-α(P>0.05).Conclusions Compared with only supplying EN or PN,Alanyl-glutamine-enriched enteral nutrition can maintain gut mucosal barrier function,reduce inflammation,increase intestinal epithelial occludin protein expression,and finally improve the gut mucosal barrier function recovery after gastrointestinal surgery.