Arana Maite Rocío, Tocchetti Guillermo Nicolás, Zecchinati Felipe, Londero Ana Sofía, Dominguez Camila, Perdomo Virginia, Rigalli Juan Pablo, Villanueva Silvina Stella Maris, Mottino Aldo Domingo
Instituto de Fisiología Experimental (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Suipacha 570, 2000, Rosario, Argentina.
Instituto de Fisiología Experimental (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Suipacha 570, 2000, Rosario, Argentina; Instituto de Biología Molecular y Celular de Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Suipacha 570, 2000, Rosario, Argentina.
Toxicology. 2017 Sep 1;390:22-31. doi: 10.1016/j.tox.2017.08.007. Epub 2017 Aug 23.
Multidrug resistance-associated protein 2 (Mrp2, ABCC2) and P-glycoprotein (P-gp, ABCB1) constitute essential components of the intestinal biochemical barrier that prevent incorporation of food contaminants, drugs or toxic metabolites into the blood stream. Endotoxemia induced in rats by administration of bacterial lipopolysaccharide (LPS) results in elevated intestinal permeability and toxicity of xenobiotics in part associated with down-regulation of expression and activity of Mrp2 and P-gp. We evaluated the protective effect of glucagon-like peptide 2 (GLP-2), a peptide hormone with enterotrophic properties, on Mrp2 and P-gp alterations induced by single i.p. injection of LPS (5mg/kg b.wt.) to rats. Two different protocols of GLP-2 administration, namely prevention and reversion, were examined. The prevention protocol consisted of 7s.c. injections of GLP-2 (125μg/kg b.wt.) administered every 12h, starting 60h before LPS administration. The reversion protocol consisted of 2 doses of GLP-2, starting 3h after LPS injection. Intestinal samples were collected 24h after LPS administration and expression (protein and mRNA) and activity of Mrp2 were evaluated in proximal jejunum whereas those of P-gp were studied in ileum. GLP-2 completely neutralized down-regulation of expression of Mrp2 and P-gp and loss of their respective activities induced by LPS under prevention protocol. GLP-2 was also able to prevent internalization of both transporters from the apical membrane of the enterocyte to intracellular compartments, as detected by confocal microscopy. LPS induced an increase in IL-1β and oxidized glutathione tissue levels, which were also counterbalanced by GLP-2 administration. In contrast, the reversion protocol failed to attenuate Mrp2 and P-gp down-regulation induced by LPS. We conclude that GLP-2 can prevent down-regulation of intestinal expression and activity of Mrp2 and P-gp in endotoxemic rats and that IL-1β and oxidative stress constitute potential targets of GLP-2 protective effects.
多药耐药相关蛋白2（Mrp2，ABCC2）和P-糖蛋白（P-gp，ABCB1）构成肠道生化屏障的重要组成部分，可防止食物污染物、药物或有毒代谢产物进入血流。通过给予细菌脂多糖（LPS）在大鼠中诱导的内毒素血症会导致肠道通透性升高以及异生物的毒性增加，这部分与Mrp2和P-gp表达及活性的下调有关。我们评估了具有肠营养特性的肽激素胰高血糖素样肽2（GLP-2）对单次腹腔注射LPS（5mg/kg体重）诱导的大鼠Mrp2和P-gp改变的保护作用。研究了两种不同的GLP-2给药方案，即预防和逆转方案。预防方案包括在LPS给药前60小时开始，每12小时皮下注射7次GLP-2（125μg/kg体重）。逆转方案包括在LPS注射后3小时开始给予2剂GLP-2。在LPS给药24小时后收集肠道样本，评估空肠近端Mrp2的表达（蛋白质和mRNA）及活性，而在回肠研究P-gp的表达及活性。在预防方案下，GLP-2完全中和了LPS诱导的Mrp2和P-gp表达下调及其各自活性的丧失。共聚焦显微镜检测显示，GLP-2还能够防止两种转运蛋白从肠上皮细胞顶端膜内化到细胞内区室。LPS诱导IL-1β和氧化型谷胱甘肽组织水平升高，给予GLP-2也可使其得到平衡。相比之下，逆转方案未能减轻LPS诱导的Mrp2和P-gp下调。我们得出结论，GLP-2可以预防内毒素血症大鼠肠道中Mrp2和P-gp的表达下调及活性降低，并且IL- /span>1β和氧化应激是GLP-2保护作用的潜在靶点。
