谷氨酰胺对慢性腹泻幼鼠肠黏膜修复的影响

目的探讨谷氨酰胺(Gln)对慢性腹泻幼鼠肠黏膜修复的作用。方法40只21日龄Wistar幼鼠,随机分为5组,每组8只。用高乳糖饲料喂养模型组,制备慢性腹泻模型,基础饲料喂养对照组,14d后处死模型组和对照组,以确证模型的建立。余Wistar幼鼠在造模成功后改基础饲料喂养,并分为自然恢复组、Gln干预组和正常组,继续观察7d后处死。应用高效液相色谱法检测各组幼鼠血Gln浓度,光镜和电镜观察幼鼠小肠的形态学变化,应用免疫组化技术检测肠黏膜的增殖细胞核抗原(PCNA)表达。结果模型组腹泻率达100%,平均每日腹泻指数为1.16±0.06,对照组幼鼠腹泻率与腹泻指数均为0(P均<0.01),说明模型制作成功。自然恢复组的体重、Gln浓度、绒毛高度、绒毛面积和PCNA数量均低于正常组(P<0.01);Gln干预组体重、绒毛高度、绒毛面积仍低于正常组,但Gln浓度和PCNA数量已恢复至正常水平,与正常组比较差异无统计学意义(P>0.05);Gln干预组除体重外,其余4项指标均高于自然恢复组(P<0.01)。结论慢性腹泻时,幼鼠出现营养不良,肠黏膜受损,肠黏膜增殖减慢,伴血Gln浓度下降;补充Gln可促进慢性腹泻后幼鼠的隐窝细胞增殖,使肠黏膜修复加快。

Effect of glutamine on small intestinal repair in weanling rats after chronic diarrhea

OBJECTIVE: To investigate the nutrient effect of glutamine on small intestinal repair in weanling rats after chronic diarrhea. METHODS: Forty 21-day-old wistar rats were randomly divided into five groups (8 in each). Animal model of chronic diarrhea was induced by a lactose enriched diet in the weanling Wistar rat, normal control group was fed with a standard semipurified diet, and after 14 days the rats in both groups were killed to test the establishment of the model. After the establishment of the model, the other groups were fed with the standard semipurified diet to recover for 7 days, and were randomly divided into three groups: non-intervention group, glutamine (Gln)-intervention group and control group. Glutamine concentrations in blood was detected by high-performance liquid chromatography (HPLC). Morphological changes including villus height and villus surface area of the jejunum were measured under a light microscope and electron microscope, expression of proliferating cell nuclear antigen (PCNA) as an index of cell proliferation was observed using immunohistochemical staining and image analysis. RESULTS: The diarrhea rate in model group was 100 percent, average diarrhea index was 1.16 +/- 0.06, but both diarrhea rate and average diarrhea index in control group were 0 (P < 0.01), which affirmed establishment of the model. There was significant decrease of body weight, plasma Gln concentration, villus height, villus surface area and expression of PCNA in non-intervened group compared with the control group (P < 0.01). There was still significant decrease of body weight, villus height and villus surface area in Gln-intervened group compared with control group (P < 0.01), but plasma Gln concentration and expression of PCNA in Gln-intervened group had recovered to normal (P > 0.05). And compared with non-intervened group, except for body weight (P > 0.05), plasma glutamine, villus height, villus surface area and expression of PCNA were all significantly increased in Gln-intervened group. CONCLUSION: Chronic diarrhea can induce malnutrition and reduce the villus height, villus surface area, expression of PCNA and plasm glutamine concentration. Oral glutamine could improve the proliferation of crypt cell and promote repair of intestinal mucosa after chronic diarrhea.