添加丙氨酰谷氨酰胺胃肠外营养对烫伤大鼠空肠黏膜及蛋白质代谢的作用

Effect of alanyl-glutamine supplemented total parenteral nutrition on intestinal mucosa and protein metabolism in burned rats

目的:探讨添加丙氨酰谷氨酰胺(Ala-Gln)全胃肠外营养(TPN)对烫伤大鼠空肠黏膜及蛋白质代谢的影响。方法:将33只SD大鼠随机分为非烫伤正常参照组(正常组)、传统TPN组(传统组)和添加二肽TPN组(二肽组)3组,每组11只。正常组自由饮食,另两组大鼠在颈外静脉插管后行30%体表面积Ⅲ度烫伤,并接受等热量(780kJ·kg-1·d-1)等氮量(氮量1.8g·kg-1·d-1,二肽组48%的氮量由Ala-Gln提供)TPN7d,留取24h尿测每日氮平衡和累积氮平衡;7d后取血测定总蛋白(TP)、白蛋白(ALB)、前白蛋白(PAB)、转铁蛋白(TRF),高效液相色谱法检测肌肉中谷氨酰胺(Gln)的含量;取一段空肠作黏膜形态学观察。结果:血清PAB、TRF及肌肉中Gln含量二肽组明显高于传统组(P<0.01);空肠黏膜绒毛高度、隐窝深度、黏膜厚度、绒毛表面积二肽组明显高于传统组(P<0.01)。结论:烫伤大鼠应用添加Ala-Gln的TPN能改善机体氮平衡,促进机体蛋白质合成,减缓肌肉中Gln含量的下降,减轻空肠黏膜的萎缩。

Objective To evaluate the effect of alanyl-glutamine （Ala-Gln） supplemented of total parenteral nutrition （TPN） on intestinal mucosa and protein metabolism in burned rats. Methods Thirty-three SD rats were divided into three groups equally：chow group, conventional TPN group （convention group） and Ala-Gln supplemented TPN group（ Ala-Gln group）. The chow group received standard chow; the two TPN groups having been placed a central venous catheter subjected to 30% TBSA Ⅲ° burn and received isocaloric （ 780 kJ·kg^-1·d^- 1 ） and isonitrogenous （ N 1.8 g·kg^-1·d^-1 ,48% of nitrogen was supplied with Ala-Gln in Ala-Gln group） TPN for 7 days. Nitrogen balance（NB） and cumulated nitrogen balance （CNB） were monitored. At the end of TPN, serum total protein （ TP）, albumin （ ALB）, prealbumin（PAB）, transferrin （TRF）, Gln in muscle were monitored. Jejunal mucosal morphological changes were observed under light microscope. Results Serum PAB, TRF, Gln level in muscle and CNB in Ala-Gln group were significantly higher than those in convention group（P 〈0.01 ）. The jejunal villus height, crypt depth, mucosal thickness and villous surface area increased significantly in Ala-Gln group. Conclusion Ala-Gln supplemented TPN in burned rats can promote protein anabolism, improve nitrogen balance, attenuate the decline in Gln in muscle and intestinal mueosal atrophy.