谷氨酰胺对失血性休克幼兔肠屏障功能保护作用的研究

Protective effects of glutamine on the intestinal mucosal barrier in young rabbits under hemorrhagic shock

目的谷氨酰胺(Gln)是一种具有多种生物活性作用的“条件必需氨基酸”,研究表明Gln在危重病中起着重要的作用,主要是因为其对多脏器尤其是胃肠道的特定保护作用。该文通过建立幼兔失血性休克模型,探讨胃肠给予不同剂量谷氨酰胺是否对幼年动物肠黏膜屏障功能具有保护作用,失血性休克时是否有肠道细菌移位导致全身炎症反应综合征(SIRS),以及Gln可否抑制SIRS的进程。方法18只幼兔随机分成3组:对照组、小剂量Gln组(LGln)、大剂量Gln组(HGln)。对照组自由进食,而小、大剂量Gln组除自由进食外,通过胃管分别补充Gln,小剂量每日0.5g/kg,大剂量每日1.0g/kg,7d后通过股动脉放血造成失血性休克模型。在休克前、复苏成功后2,6,24h取外周血,测定血浆二胺氧化酶(DAO)含量及血清白介素8(IL8)水平;取距回盲部近端5cm处回肠组织进行光镜组织形态学观察,淋巴细胞分布和多形核中性粒细胞(PMN)计数,并测量回肠绒毛高度、宽度和表面积。结果LGln和HGln两组在复苏成功后6h,24h血中DAO含量明显低于对照组(P<0.05或P<0.01);IL8水平(pg/mL)明显低于对照组(P<0.05或P<0.01);补充Gln组较对照组血中肠黏膜PMN计数、淋巴细胞百分比明显降低(P<0.01或P<0.05);对照组回肠绒毛上皮脱落、萎缩,高度降低、表面积减少,(P<0.01或P<0.05),3组绒毛宽度比较无统计学意义。小、大剂量Gln组之间各检测指标以及组织形态学差异均无显著性。结论在有效剂量范围内,胃肠补充Gln对幼年动物失血性休克后肠屏障功能都具有保护作用,可能对SIRS的进程有一定的抑制作用。

Objective Glutamine （Gin） is now considered as conditionally essential amino acid with many biological activities. This study aimed to investigate whether it has protective effects on the intestinal mucosal barrier in young rabbits under hemorrhagic shock. Methods Eighteen young rabbits aged 26 ± 3 days were randomly assigned into 3 groups： Control （ no treatment）, Low-dose Gin （ L-Gln,0.5 g/kg daily） and High-dose Gin （ H-GIn, 1.0 g/kg daily） treatment groups. Gin was administered by gastric tube daily for 7 days and then hemorrhagic shock was induced by blood withdrawing from femoral artery. Plasma levels of diamine oxidase （DAO） and serum levels of interleukin-8 （ IL-8 ） were measured before shock, and at 2, 6 and 24 hrs after resuscitation. Ileum tissues located approximately 5 cm away from the ileocecal valve was removed for histological examination, lymphocyte distribution, polymorphonuclear（ PMN ） count and assessing the height, width and surface area of the villi. Results Plasma levels of DAO and serum levels of IL-8 at 6 and 24 hrs after resuscitation in the L-GIn and the H-GIn groups decreased significantly compared with those of the Control group. L-GIn and H-GIn also resulted in a decrease in the PMN counts and the lymphocyte percentage in the ileum compared with the Control group. Exfoliation and atrophy of villous epithelial cells occurred and the height and surface area of villous were reduced in the Control group. The ileum morphology of the two Gin treatment groups was found to be nearly normal. There were no differences between the L-GIn and the H-GIn groups. Conclusions Gin within a therapeutic dose has protective effects on intestinal mucosal barrier in young rabbits under hemorrhagic shock.