不同剂量早期肠内营养对肠缺血再灌注损伤大鼠骨骼肌高分解代谢的影响

Effects of different doses of early enteral nutrition on hypercatabolism of skeletal muscle in rats with intestinal ischemia-reperfusion injury

目的明确肠内营养(EN)最佳剂量对调节骨骼肌高分解代谢有重要意义。文中旨在对不同剂量EEN对骨骼肌高分解代谢的作用进行研究。方法将40只Sprague-Dawley大鼠随机分为4组(每组8只):60%EN组(给予60%肠内营养)、20%EN+40%PN组(给予20%肠内营养+40%肠外营养)、40%EN+20%PN组(给予40%肠内营养+20%肠外营养)和60%PN组(给予60%肠外营养)。所有大鼠均进行肠系膜上动脉缺血再灌注损伤(I/R)干预。营养干预3 d后处死大鼠,检测骨骼肌代谢产物3-甲基组氨酸(3-MH)和酪氨酸水平、萎缩基因(MURF-1、MAFbx)mRNA及相关蛋白的表达、血TNF-α和IL1-β水平。结果20%EN+40%PN组、40%EN+20%PN组体重改变程度[(-0.117±0.041)%、(-0.136±0.037)%]较60%PN组[(-0.180±0.005)%]、60%EN组[(-0.174±0.058)%]显著减轻(P<0.05),趾长伸肌/体重比显著增高(P<0.05)。与60%PN组和60%EN组比较,20%EN+40%PN组、40%EN+20%PN组3-MH及酪氨酸水平显著降低(P<0.05),MURF-1及MAFbx水平显著降低(P<0.05),血TNF及IL-1β显著降低(P<0.05)。其中,20%EN+40%PN组差异更显著。结论不同剂量肠内营养对骨骼肌高分解代谢的影响不同,20%EN+40%PN的营养方式有助于减轻肠I/R损伤大鼠急性骨骼肌高分解代谢。

Objective To determine the optimal dose of enteral nutrition(EN)for regulating skeletal muscle hypercatabolism is important.This study aims to study the effect of EEN in different doses on hypercatabolism of skeletal muscle.Methods 40 Sprague-Dawley rats were randomly divided into 4 groups(8 rats in each group):60%EN group(60%enteral nutrition),20%EN+40%PN group(20%enteral nutrition+40%parenteral nutrition),40%EN+20%PN group(40%enteral nutrition+20%parenteral nutrition)and 60%PN group(60%parenteral nutrition).All rats were treated with superior mesenteric artery ischemia/reperfusion injury(I/R)intervention.The levels of skeletal muscle metabolites 3 methylhistidine(3 MH)and tyrosine,the expression of MURF 1 and MAFbx mRNA and related proteins,and the levels of TNFαand IL1βin blood were detected.Results The body weight change degree of 20%EN+40%PN group[(-0.117±0.041)%,(-0.136±0.037)%]was significantly lower than that of 60%PN group[(-0.180±0.005)%]and 60%EN group[(-0.174±0.058)%](P<0.05),extensor digitorum longus muscle/body weight ratio was significantly increased(P<0.05).Compared with 60%PN group,the levels of 3 MH and tyrosine in 20%EN+40%PN and 40%EN+20%PN groups were significantly decreased(P<0.05).Compared with 60%EN group,MuRF-1 level in 20%EN+40%PN and 40%EN+20%PN groups was significantly decreased(P<0.05),and MAFbx level in 20%EN+40%PN group was significantly decreased(P<0.05).Compared with 60%PN and 60%EN group,the levels of TNFαand IL 1βin 20%EN+40%PN and 40%EN+20%PN groups were significantly decreased(P<0.01).Conclusion The effects of different doses of enteral nutrition on skeletal muscle hypercatabolism are different,and 20%EN+40%PN can alleviate acute skeletal muscle hypercatabolism in rats with intestinal I/R injury.