大鼠小肠缺血再灌注时肠内给予不同营养物对肠黏膜吸收功能和能量代谢的影响

目的 探讨肠缺血再灌注损伤时肠内给予不同营养物对小肠吸收功能和ATP含量的影响。方法 SD大鼠分为3组,先制作空肠袋,分别向袋内注射葡萄糖、丙氨酸、甘露醇以及葡萄糖／丙氨酸混合液。用动脉夹阻断肠系膜上动脉血流60min后,再恢复灌流60min。分别测定反应肠黏膜吸收功能的短回路电流的变化（ΔIsc）和肠黏膜ATP含量。结果 缺血再灌注时肠黏膜ΔIsc和ATP显著降低,给予丙氨酸或葡萄糖／丙氨酸混合液使肠黏膜ΔIsc值和ATP含量进一步降低;而给予葡萄糖组ΔIsc和ATP含量不仅显著高于丙氨酸组和葡萄糖／丙氨酸混合液组,而且也显著高于单纯缺血再灌注组。结论 肠内给予丙氨酸能加重缺血再灌注引起的肠黏膜能量代谢和吸收功能障碍,而肠内给予葡萄糖能改善肠黏膜能量代谢和吸收功能,对缺血再灌注损伤的肠道提供保护作用。

Effects of different enteral nutrients on gut absorptive capacity and energy metabolism during gut ischemia/reperfusion

OBJECTIVE: To evaluate the effects of different enteral nutrients on intestinal absorptive capacity and ATP content of intestinal mucosa after ischemia-reperfusion (I/R) of the intestine. METHODS: A segment of jejunum was isolated to form a pouch in Sprague-Dawley rats. The jejunal pouches of animals were filled with either a mixture of nutrients (5 mmol/L alanine + 5 mmol/L glucose), glucose alone (10 mmol/L), alanine alone (10 mmol/L) or mannitol alone (10 mmol/L) as a nonabsorbable osmotic control. The superior mesenteric artery was then occluded for 60 minutes, followed by reperfusion for 60 minutes. Gut absorptive capacity, as measured by the changes in short circuit current (DeltaIsc), and mucosal ATP content were determined both at the end of 60 minutes ischemia and 60 minutes of reperfusion. RESULTS: DeltaIsc and ATP levels were decreased after I/R. Intraluminal alanine alone or alanine/glucose mixture further reduced DeltaIsc and ATP content.On the other hand, intraluminal glucose significantly increased DeltaIsc and ATP levels compared with intraluminal alanine, alanine/glucose mixture or I/R alone. CONCLUSION: Intraluminal alanine increases the absorptive capacity and energy metabolism of the gut caused by I/R, and indicated that intraluminal glucose improves gut absorptive capacity and energy metabolism and provides a protective effect on gut from ischemia and reperfusion injury.