精氨酸防治全胃肠外营养所致肠屏障功能损伤的实验研究

Protective role of arginine in gut barrier dysfunction induced by total parenteral nutrition

目的研究精氨酸对全胃肠外营养(TPN)所致肠屏障功能损伤的防治作用。方法24只幼兔,随机分为3组。正常对照组右侧颈静脉结扎后自由饮食,其余两组经右颈静脉插入硅胶管,标准TPN组输注标准TPN液[175kcal/(kg·d),200ml/(kg·d)],精氨酸强化TPN组输注精氨酸占总热卡2%的等氮等热卡的TPN液。7d后分别取血浆及回肠标本观察肠黏膜形态学改变、肠菌移位率、血浆和回肠组织二胺氧化酶(diamine oxidase,DAO)活性、血浆D!乳酸含量。结果肠黏膜在标准TPN组变薄、萎缩(P<0.01),而精氨酸强化TPN组肠黏膜的萎缩较标准TPN组减轻(P<0.05);精氨酸强化TPN组肠菌移位率较标准TPN组显著降低(P<0.05),与正常对照组差异无统计学意义(P>0.05);精氨酸强化TPN组血浆和回肠组织DAO活性较标准TPN组升高(P<0.05),与正常对照组差异无统计学意义(P>0.05);精氨酸强化TPN组血浆D!乳酸含量较标准TPN组降低(P<0.01),较正常对照组仍偏高(P<0.05)。结论精氨酸对维持肠黏膜形态和功能的完整性具有重要作用,添加适量外源性的精氨酸具有改善TPN所致小肠黏膜损伤的作用。

Objectives To investigate the protective role of arginine in gut barrier dysfunction induced by total parenteral nutrition （TPN）. Methods Twenty-four young rabbits were randomly and equally divided into 3 groups： control group, standard TPN group and arginine-enriched TPN group. After ligation of the right jugular vein, the control rabbits were allowed free access to chow and water ad libitum, while animals in other two groups received either standard TPN （175 kcal/（kg·d） 200 ml/（kg·d）） or arginine-enriched TPN （account for 2% of total energy） via a silastic catheter leading to the superior vena cava. After 7 days of TPN administration, plasma and ileum were collected to determine the intestinal morphological changes, incidence of bacterial translocation, diamine oxidase （DAO） activity and plasma D-lactic acid level. Results （1） The mucosal thickness, villus height and surface area in the standard TPN group were significantly lower than those in the control group （P 〈 0.01） and the arginine-enriched TPN group （P 〈 0.05） . There was no significant difference in the above parameters between the control group and the arginine-enriched TPN group; （2） The incidence of bacterial translocation in standard TPN group was significantly higher than that in the control group （P 〈 0.01） and in the arginine enriched-TPN group （P 〈 0.05） . There was no significant difference between the later two groups in the incidence of bacterial translocation; （3） The activity of plasma and ileum DAO in the standard TPN group was significantly lower than that in the control group （P 〈 0.01 ） and the arginine enriched-TPN group （P 〈 0.05） . There was no significant difference between the later two groups in the activity of plasma and ileum DAO; （4） The plasma D-lactic acid level in standard TPN group was significantly higher than that in the control group （P 〈 0.01 ） . The plasma D-lactic acid level in the arginine enriched- TPN group was significantly lower than that in the standard TPN group （P 〈 0.01 ） but still higher than that in the control group （P 〈 0.01 ） . Conclusions The arginine plays an important role in maintaining the integrity of gut barrier. Arginine supplement could prevent the intestinal mucosal injury caused by TPN administration.