【摘要】 目的:研究丙氨酰-谷氨酰胺(Ala -Gln)对口服FK506损伤的肠黏膜组织中iNOS和TNF-α分子表达的影响。方法:BALB/c小鼠24只,随机分成对照组、FK506低剂量组、FK506高剂量组及Ala -Gln治疗组,分别给以0.2 mL生理盐水、FK506 0.1 mg/kg、1.0 mg/kg灌胃和FK506 1.0 mg/kg灌胃及丙氨酰-谷氨酰胺0.5 g/kg腹腔注射。隔天给药,6周后采集回肠标本。HE染色和扫描电镜观察肠黏膜组织形态学改变;FITC -dextran(FD4)检测肠黏膜通透性;RT-PCR检测小肠黏膜iNOS和TNF-α mRNA的表达情况;Western blotting检测iNOS和TNF-α蛋白表达水平。结果:FK506高剂量组的肠黏膜对FD4的通透性明显增加,扫描电镜示小肠绒毛破坏明显,而Ala -Gln治疗组小肠绒毛破坏减轻,对FD4的通透性下降;FK506高剂量组小肠黏膜iNOS mRNA和TNF-α mRNA表达增强,而Ala -Gln治疗组表达则明显下调;iNOS和TNF-α蛋白表达水平的变化与此一致。结论:FK506通过上调iNOS和TNF-α的表达对小肠黏膜产生损伤,使小肠壁的通透性增加。Ala -Gln对FK506所致的肠黏膜屏障功能损伤具有保护作用,该作用可能与下调iNOS和TNF-α的表达有关。更多还原

【Abstract】 AIM: To investigate the effects of alanyl-glutamine (Ala-Gln) on expression of iNOS and TNF-α in injured intestinal mucosa induced by oral tacrolimus(FK506). METHODS: Twenty-four BALB/c mice were randomized to receive orally 0.2 mL of normal saline solution ( groupⅠ), 0.2 mL of FK506 in a dose of 0.1 mg/kg (groupⅡ) or 1.0 mg/kg (groupⅢ), and orally high-dose FK506 (0.2 mL, 1.0 mg/kg) plus intraperitoneal injection of Ala-Gln (0.5 g/kg )(groupⅣ),respectively. Damages of intestinal mucosa were determined by pathological examination. Intestinal mucosal permeability was analysed by FITC-dextran fluorescence assay. Expression of iNOS and TNF-α in intestine was detected by RT-PCR and Western blotting.RESULTS: Severe damage on the villi and increased intestinal permeability were observed in high-dose FK506 treated mice according to scanning electron microscopy and FITC-dextran flux respectively. The erosion and increased intestinal permeability were significantly alleviated by Ala-Gln treatment. Transcription of iNOS mRNA and TNF-α mRNA, which was up-regulated in high-dose FK506 treated group, was also markedly down-regulated in mice combined with Ala-Gln-treatment. A significantly increased expression of iNOS and TNF-α protein was found in the high-dose FK506 treated mice, while small amounts of these proteins were identified in the Ala-Gln-treated group.CONCLUSION: FK506 could induce a significant impairment of intestinal mucosa morphologically, which might be associated with up-regulated expression of iNOS and TNF-α in small intestinal mucosa. Subsequently, the intestinal permeability is increased. Ala-Gln has a strong protective effect on FK506-induced intestinal barrier dysfunction, probably relates to the down-regulation of iNOS and TNF-α expression.更多还原