超早期肠内营养对重度急性胰腺炎大鼠肠黏膜屏障功能的影响

Early enteral nutrition improves intestinal barrier function in rats with severe acute pancreatitis

目的:探讨超早期肠内营养(enteral nutrition,EN)对重度急性胰腺炎(severe acute pancreatitis,SAP)大鼠肠黏膜屏障功能的影响.方法:将60只♂SD大鼠分为假手术组(Sham组15只)、SAP空白对照组(SAP组15只)、肠内营养组(EN组15只)、肠外营养组(parenteral nutrition,PN组15只).SAP大鼠模型制作采用逆行胆胰管注射5%牛磺胆酸钠法,假手术组以生理盐水代替.假手术组与SAP空白对照组在术后6 h给予生理盐水,其他2组在术后6 h分别给予肠内、肠外营养液支持治疗.所有组均在造模后第48小时处死大鼠.处死前抽取外周血检测血浆淀粉酶、内毒素、二胺氧化酶的含量.各组取胰腺组织分别计算胰腺病理评分和胰腺脓肿发生率;各组取末端回肠组织常规光镜观察回肠末端黏膜形态学变化,测量黏膜厚度和绒毛高度.结果:SAP空白对照组大鼠血浆内毒素和二胺氧化酶水平分别为0.545 EU/mL±0.095EU/mL、1.52 U/mL±0.09 U/mL,PN组大鼠二者血浆水平分别下降为0.333 EU/mL±0.046EU/mL、1.17 U/mL±0.10 U/mL,EN组大鼠则继续下降至0.247 EU/mL±0.069 EU/mL、0.91 EU/mL±0.13 EU/mL,与SAP空白对照组比较,EN组内毒素水平(P<0.01),与PN组比较,EN组内毒素水平(P<0.05);与前两组比较,EN组二胺氧化酶水平(P<0.01).SAP空白对照组、EN组、PN组血浆淀粉酶水平分别为10171 U/L±665.77 U/L、9428.2 U/L±1076.61 U/L、10533 U/L±1669.13 U/L,三组间比较无显著差异.胰腺病理评分:SAP空白对照组14.50±1.05、PN组10.44±1.01,EN组8.08±1.24,与前两组比较,EN组有显著差异(P<0.01);胰腺脓肿发生率:SAP空白对照组9/15、PN组6/15、EN组2/15,三组比较无显著差异.末端回肠黏膜病理分析显示:SAP空白对照组大鼠末端回肠黏膜厚度和绒毛高度分别为226.67μm±20.84μm、137.33μm±9.38μm,EN组大鼠294.79μm±20.49μm、194.54μm±11.96μm,PN组大鼠306.11μm±24.34μm、201.72μm±10.60μm,与SAP空白对照组相比,EN组和PN组大鼠回肠黏膜厚度及绒毛高度明显改善(P<0.01),但EN组和PN组比较未见显著差异.结论:超早期肠内营养能改善SAP大鼠肠道屏障功能,减轻肠源性内毒素血症.

AIM： To investigate the effect of early enteral nutrition on the intestinal barrier function in rats with severe acute pancreatitis （SAP）. METHODS： Sixty male Sprague-Dawley ratswere randomly allocated into 4 groups： a shamoperation group （n =15）, an SAP group （control group, n =15）, a parenteral nutrition group （PN group, n= 15） and an enteral nutrition.group （EN group, n= 15）. SAP was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Rats in the sham-operation group only underwent laparotomy without induction of SAP. Six hours after surgery, rats in the former two groups were given normal saline, while those in the latter two groups were administrated with EN and PN, respectively. All rats were sacrificed 48 h after operation. Serum levels of amylase （AMS）, endotoxin and diamine oxidase （DAO） were detected. Pathological changes of the pancreas were observed by light microscopy. The incidence of pancreatic abscess was calculated. The sections of terminal ileum were obtained to measure the height of villi and the thickness of the mucosa. RESULTS： Plasma levels of endotoxin and DAO were significantly lower in the EN group than in the SAP group and PN group （endotoxin： 0.247 EU/mL ± 0.069 EU/mL vs 0.545 EU/mL ± 0.095 EU/mL, 0.333 EU/mL ± 0.046 EU/mL; P 〈 0.05 for the PN group, P 〈 0.01 for the SAP group; DAO： 0.91 EU/mL ± 0.13 EU/mL vs 1.52 U/mL ± 0.09 U/mL, 1.17 U/mL ± 0.10 U/mL; P 〈 0.01 for both）. There were no significant differences in plasma amylase （AMS） between the SAP group, EN group and PN group （10171 U/ L ±665.77 U/L vs 9428.2 U/L ±1076.61 U/L vs 10533 U/L ± 1669.13 U/L）. The histological score of the injured pancreas in the EN group was markedly decreased in comparison with those in the SAP group and PN group （8.08 ± 1.24 vs 14.50 ± 1.05, 10.44 ± 1.01; P 〈 0.01 for.both）. The rate of pancreatic abscess in the three groups was not statistically different （SAP group： 9/15, EN group： 2/15, PN group： 6/15）. Compared with the SAP group, the thickness of the mucosa and height of villi were improved obviously in both the EN group and PN group （thickness of mucosa： 226.67μm ± 20.84μm vs 294.79 μm±20.49 μm, 306.11μm ± 24.34μm; P 〈 0.01for both; height of villi： 137.33μm ± 9.38μm vs 194.54μm ± 11.96 9m, 201.72 pm ± 10.60 pm; P 〈 0.01 for both）, although there was no significant difference between the EN group and PN group. CONCLUSION： Early enteral nutrition can significantly improve the gut barrier function and ameliorate intestinal endotoxemia in rats with SAP.