Juel Ingebjørg S, Solligård Erik, Lyng Oddveig, Strømholm Tonje, Tvedt Kåre E, Johnsen Harald, Jynge Per, Saether Ola D, Aadahl Petter, Grønbech Jon Erik
Department of Surgery, St. Olav University Hospital, N-7006 Trondheim, Norway.
J Surg Res. 2004 Apr;117(2):283-95. doi: 10.1016/j.jss.2003.10.025.
The mucosal surface epithelium is an essential part of the functional intestinal barrier, but its structural response to ischemia/reperfusion is only partly characterized. The purpose of this study was to provide a detailed morphological evaluation of intestinal surface epithelium after aortic cross-clamping.
Pigs were subjected to thoracic aortic cross-clamping for 60 min and subsequent reperfusion for 120 min. Tissue blood flow and high-energy phosphates were measured with microspheres and HPLC, respectively. Urinary excretion of (14)C polyethylene glycol (MW 4000 Da) (PEG-4000), loaded into an intestinal loop, provided an index of intestinal permeability.
Jejunal blood flow was restored at 10 min after aortic declamping. Denudation of the basement membrane of the intestinal villi tips, as a consequence of epithelial shedding, increased markedly during the initial 60 min of reperfusion (P = 0.002). During the following 45 min, the denuded basement membrane was partly covered with low cuboidal and squamous-shaped cells extending lamellipodia over a wavy basement membrane. Restoration of ATP at 60 min after aortic declamping correlated inversely to the extent of denuded basement membrane (r = 0.75, P = 0.032). Permeability of PEG-4000 increased markedly after aortic declamping and was linearly correlated to the area of denuded basement membrane (r = 0.87, P = 0.01).
Reperfusion for 2 h after aortic cross-clamping is associated with initial aggravation of ischemia-induced injury in the porcine jejunum, but thereafter with restitution of the surface epithelium. Restoration of ATP may be important to avoid intestinal injury after ischemia. Increased permeability of a macromolecule in response to reperfusion is closely correlated to injury of the surface epithelium.
黏膜表面上皮是功能性肠屏障的重要组成部分，但其对缺血/再灌注的结构反应仅得到部分描述。本研究的目的是对主动脉交叉钳夹后肠表面上皮进行详细的形态学评估。
猪接受胸主动脉交叉钳夹60分钟，随后再灌注120分钟。分别用微球和高效液相色谱法测量组织血流量和高能磷酸盐。将（14）C聚乙二醇（分子量4000道尔顿）（PEG - 4000）注入肠袢，通过其尿排泄量来评估肠道通透性。
主动脉夹闭解除后10分钟，空肠血流恢复。在再灌注的最初60分钟内，由于上皮脱落导致肠绒毛顶端基底膜剥脱显著增加（P = 0.002）。在接下来的45分钟内，剥脱的基底膜部分被低立方状和鳞状细胞覆盖，这些细胞在波浪状的基底膜上伸出片状伪足。主动脉夹闭解除后60分钟时ATP的恢复与基底膜剥脱程度呈负相关（r = 0.75，P = 0.032）。主动脉夹闭解除后PEG - 4000的通透性显著增加，且与基底膜剥脱面积呈线性相关（r = 0.87，P = 0.01）。
主动脉交叉钳夹后2小时的再灌注与猪空肠缺血性损伤的最初加重相关，但随后表面上皮会恢复。ATP的恢复对于避免缺血后肠损伤可能很重要。大分子在再灌注后通透性增加与表面上皮损伤密切相关。
