高亮氨酸肠外营养对兔烧伤后蛋白质丢失的影响

目的观察不同浓度亮氨酸的肠外营养液对烧伤后家兔肌肉蛋白质丢失的影响,并探讨其机制。方法 40只新西兰兔,经沸水造成15%面积的III度烧伤,7d后给予不同的静脉营养支持,分别为普通糖水(Glu组)、基础肠外营养(BPN组)、支链氨基酸肠外营养(BCAA组)、和高亮氨酸肠外营养(Leu组)。其中BPN,BCAA,Leu组肠外营养液按等氮等能量配置,亮氨酸分别占总氨基酸的6.9%、12.8%、35.9%。营养支持1h后开始L-1-13C]-苯丙氨酸同位素示踪测定兔下肢肌肉的蛋白质代谢情况。结果与Glu组相比,BCAA组和Leu组蛋白合成速率均有显著提高,且以Leu组更为明显(+206%vs+99%);三组中,只有Leu组有明显改善蛋白平衡的作用,并获得正蛋白平衡0.38±0.10 g/(kg.d)vs-0.74±0.40 g/(kg.d)]。Glu组和BPN组之间、BPN组和BCAA组之间的各项蛋白质代谢参数均无统计学差异。结论高亮氨酸营养液可有效改善烧伤后兔肌肉的蛋白质丢失,其作用主要通过促进蛋白质合成代谢实现。营养学报,2012,34(6):549-552]

EFFECTS OF LEUCINE-ENRICHED PARENTERAL NUTRITION ON PROTEIN LOSS AFTER BURN INJURY IN RABBITS

Objective To investigate the effects of leucine-enriched parenteral nutrion protein loss after burn injury in rabbits and its mechanism.Method Forty New Zealand white rabbits were inflicted with 15% total body surface area full thickness burn and given parenterally different nutrition supports including glucose(Glu group),basal and parenteral nutrition(BPN group),BCAA-enriched PN(BCAA group),and leucine-enriched PN(Leu group).Three parenteral nutrition flaids were infused both isonitrogenously and isocalorically 7 d later.The ratio of leucine to total amino acids was 6.9%,12.8% and 35.9% respectively.A stable isotope tracer research with L-1-13C]-phenylalanine was started 1h after nutrition support to determine hindquarter muscle protein metabolism.Results Compared to Glu group,protein synthesis rates of BCAA group and Leu group were both elevated significantly,and the latter group showed more significannce(+206% vs +99%).Among the three parenteral nutrition groups,only Leu improved the muscle protein balance,and obtained a positive protein balance 0.38±0.10 g/(kg.d) vs-0.74±0.40 g/(kg.d)].The protein metabolic parameters between Glu group and BPN group,BPN group and BCAA group did not differ significantly.Conclusion Leucine-enriched parenteral nutrition can reduce protein loss effectively in rabbits after burn injury by increasing muscle protein synthesis.ACTA NUTRIMENTA SINICA,2012,34(6):549-552]