Yang Yang, Qiu Yuan, Wang Wensheng, Xiao Weidong, Liang Hongyin, Zhang Chaojun, Yang Hanwenbo, Teitelbaum Daniel H, Sun Li-Hua, Yang Hua
Department of General Surgery, Xinqiao Hospital, Third Military Medical University Chongqing, China.
University of Michigan Ann Arbor, MI, USA.
Int J Clin Exp Pathol. 2014 Apr 15;7(5):2006-18. eCollection 2014.
Intestinal barrier function failure from ischemia/reperfusion (I/R) and acute hypoxia has been implicated as a critical determinant in the predisposition to intestinal inflammation and a number of inflammatory disorders. Here, we identified the role of Adenosine A2B receptor (A2BAR) in the regulation of intestinal barrier function under I/R and acute hypoxic conditions.
C57BL/6J mice were used, and were randomized into three groups: Sham, I/R, IR+PSB1115 (a specific A2BAR antagonist) groups. After surgery, the small bowel was harvested for immunohistochemical staining, RNA and protein content, and intestinal permeability analyses. Using an epithelial cell culture model, we investigated the influence of hypoxia on the epithelial function, and the role of A2BAR in the expressions of tight junction and epithelial permeability. The expressions of Claudin-1, occludin and ZO-1 were detected by RT-PCR and Western-Blot. Epithelial barrier function was assessed with transepithelial resistance (TER).
The A2BAR antagonist, PSB1115, significantly increased tight junction protein expression after intestinal I/R or acute hypoxia conditions. PSB1115 also attenuated the disrupted distribution of TJ proteins. Furthermore, inhibition of A2BAR attenuated the decrease in TER induced by I/R or acute hypoxic conditions, and maintained intestinal barrier function. Antagonism of A2BAR activity improves intestinal epithelial structure and barrier function in a mouse model of intestinal I/R and a cell model of acute hypoxia. These findings support a potentially destructive role for A2BAR under intestinal I/R and acute hypoxic conditions.
缺血/再灌注（I/R）和急性缺氧导致的肠屏障功能衰竭被认为是肠道炎症和许多炎症性疾病易感性的关键决定因素。在此，我们确定了腺苷A2B受体（A2BAR）在I/R和急性缺氧条件下对肠屏障功能调节中的作用。
使用C57BL/6J小鼠，并将其随机分为三组：假手术组、I/R组、I/R + PSB1115（一种特异性A2BAR拮抗剂）组。手术后，收集小肠进行免疫组织化学染色、RNA和蛋白质含量以及肠道通透性分析。使用上皮细胞培养模型，我们研究了缺氧对上皮功能的影响，以及A2BAR在紧密连接表达和上皮通透性中的作用。通过RT-PCR和蛋白质免疫印迹法检测Claudin-1、闭合蛋白和ZO-1的表达。用跨上皮电阻（TER）评估上皮屏障功能。
A2BAR拮抗剂PSB1115在肠道I/R或急性缺氧条件下显著增加紧密连接蛋白表达。PSB1115还减弱了TJ蛋白的分布紊乱。此外，抑制A2BAR减弱了I/R或急性缺氧条件诱导的TER降低，并维持了肠屏障功能。在肠I/R小鼠模型和急性缺氧细胞模型中，拮抗A2BAR活性可改善肠上皮结构和屏障功能。这些发现支持了A2BAR在肠道I/R和急性缺氧条件下具有潜在破坏作用的观点。
