谷氨酰胺对急性坏死型胰腺炎大鼠肠道衰竭的治疗作用

Effects of glutamine on the intestinal failure in rats model of acute necrotizing pancreatitis

目的 观察谷氨酰胺 (Gln)对急性坏死型胰腺炎 (ANP)大鼠肠道衰竭的治疗作用 ,并探讨其作用机制。方法 Spraque Dawley大鼠 5 4只 ,随机分为假手术组 (SO)、ANP组、Gln治疗组 (ANP +Gln) ,每组 18只。采用 5 %牛磺胆酸钠溶液经胆胰管内逆行注射诱导大鼠ANP模型。大鼠中心静脉置管 ,用微量输液泵输注含等氮、等热卡的氨基酸溶液 ,ANP +Gln组加入 3%丙氨酸 Gln双肽 (相当于2 %Gln溶液 ,剂量 0 5g·kg-1·d-1)。术后 2 4、48、72h分批处死大鼠并留取标本 ,分别做肠黏膜组织病理检查 ,肝、胰、脾、肠系膜淋巴结 (MLN)和腹水等组织细菌培养 ,门静脉血内毒素测定 ,TUNEL法检测肠黏膜上皮细胞凋亡 ;逆转录 聚合酶链反应研究肠黏膜组织胰岛素样生长因子 1(IGF 1)、Gln酶和Gln合成酶mRNA表达。结果 SO组大鼠各组织培养均无阳性细菌 ,ANP组细菌培养阳性率明显高于SO组 ,P <0 0 5 ,以MLN阳性率最高 ;ANP +Gln组细菌培养阳性率则显著低于ANP组 ,P <0 0 5。血浆内毒素在ANP组明显高于SO组 (P <0 0 5 ) ,且随着时间延长而递升 ;ANP +Gln组血浆内毒素较ANP组显著下降 (P <0 0 5 )。ANP组肠黏膜绒毛高度显著低于SO组 (P <0 0 5 ) ,提示ANP时肠黏膜处于萎缩状态 ,而ANP +Gln组较SO组则差异无显著性 (P >0 0 5 )

Objective To determine the effects of glutamine (Gln) on the intestinal failure in rats with acute necrotizing pancreatitis (ANP) and its possible mechanisms. Methods Fifty-four Spraque-Dawley rats were randomly divided into 3 groups: sham operation (SO, n=18), ANP (n=18), and ANP treated with Gln (ANP+Gln, n=18). ANP model was induced by injection of 5% sodium taurocholate solution into bilo-pancreatic duct. The therapy was continuously given with amino acid solution by a mini-pump via a central intravenous line. In addition, the ANP+Gln group was received 3% Gln dipeptide solution (equal to 2% Gln) with a dosage of 0.5g·kg -1·d -1. These groups were isocaloric and isonitrogenous. Bacterial cultures from pancreas, mesenteric lymph node (MLN), liver, spleen and acites were done at 24, 48, 72 h after operation. Endotoxin level in portal vein was determined. Pathologic changes of intestinal mucosa were also studied. Apoptosis of intestinal mucosa was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method. Expressions of insulin-like growth factor 1 (IGF-1), Gln synthetase (GSase) and glutaminase (Glnase) mRNA were assayed by reverse transcription polymerase chain reaction (RT-PCR). Results At 24, 48, 72h, the positive rate of bacterial culture and the endotoxin concentration were increased significantly in ANP group compared to the SO group (P<0.05), while Gln could decrease them significantly. Pathologic study showed that the height of mucosal villous in ANP group was lower than that in SO group, indicating the intestinal mucosa became more atrophy. However ,the height of mucosal villous in ANP+Gln group was no significantly difference compared to that in SO group, indicated Gln could preserve the mucosa well. Apoptotic index was increased in ANP group and decreased in Gln treated rats. Expressions of IGF-1, GSase, Glnase mRNA were down-regulated in ANP group, but were up-regulated in ANP+Gln group. Conclusions The intestinal barrier function was impaired in ANP. Gln could protect intestinal barrier function. This action was probably related to its enhancement of IGF-1, GSase and Glnase mRNA expressions and its inhibition of intestinal mucosal apoptosis.