肠内营养对脑外伤大鼠肠黏膜屏障功能及多巴胺受体的影响

目的：研究肠内营养对脑外伤大鼠肠黏膜屏障功能及多巴胺受体表达的影响，探讨有效的肠内营养方案与护理措施。方法采用Feeney自由落体脑损伤装置建立脑外伤大鼠模型，将30只大鼠随机分为对照组、谷氨酰胺组和益生菌组3组，于脑外伤第7天留取肠黏膜组织、尿液、脏器组织等标本，采用尿中乳果糖和甘露醇排泄率比值（ L/M）测定肠黏膜的通透性，HE染色观察肠黏膜形态，EMB培养法观察细菌易位，免疫组化检测DRD1和DRD2在肠黏膜组织中的表达，Real-time PCR和WB分别检测肠黏膜DRD1和DRD2的mRNA和蛋白水平。结果脑外伤后谷氨酰胺组和益生菌组大鼠体质量分别为（184．38±11．49）和（185．22±8．46）g，与对照组相比减少缓慢，差异有统计学意义（t 值分别为4．408，5．305；P＜0．05）；谷氨酰胺组和益生菌组肠黏膜绒毛结构较完整，肠黏膜DRD1和DRD2表达均降低，脏器中大肠埃希菌明显减少，尿液中L/M值分别为（0．051±0．010）和（0．038±0．009），均低于对照组，差异有统计学意义（ t值分别为26．48，29．46；P＜0．05）。结论在肠内营养中添加谷氨酰胺和益生菌可下调肠黏膜DRD1和DRD2表达水平，可能是其改善脑外伤大鼠肠黏膜屏障功能的机制之一，为脑外伤患者的营养支持与临床护理提供实证依据。

Influence of enteral nutrition on intestinal mucosal barrier function and dopamine receptors in rats with traumatic brain injury

Objective To investigate the effect of glutamine and probiotics on intestinal mucosal barrier function and expression of dopamine receptor D 1 and D2 （ DRD1 and DRD2 ） in rats with traumatic brain injury （TBI）.Methods Animal model was established by Feeney free fall TBI device .Thirty rats were randomly divided into three groups：control group , glutamine group （ Gln） , probiotics group （ PB） .The ratio of lactulose and mannitol （L/M） in urine was determined by high performance liquid chromatography （HPLC）.Bacterial translocation and intestinal mucosal morphology were evaluated by eosin methylene blue （ EMB ） culturing and hematoxylin-eosin （ HE） staining, respectively.Expression of DRD1 and DRD2 in intestinal mucosal were evaluated by immunohistochemistry , real-time PCR and western blot .Results After TBI, the weight of rats in the Gln and the PB group were （184.38 ±11.49） g and （185.22 ±8.46） g, respectively.Compared with the control group, the weight loss was significantly different （t =4.408, 5.305, respectively;P ＆lt;0.05）.The intestinal mucosal morphology was better in the Gln and the PB group , and reduced expression of DRD 1 and DRD2 and bacterial translocation were observed in these groups .The L/M in urine were （0.051 ±0.010） and （0.038 ±0.009） in the Gln and the PB group.There were significant differences （ t =26.48, 29.46, respectively;P〈0.05）.Conclusions Enteral nutrition with glutamine and probiotics can significantly improve intestinal mucosal barrier function in rats with TBI , which may be related to expression of DRD 1 and DRD2 in intestinal mucosal .