Gonzalez Ernest A, Kozar Rosemary A, Suliburk James W, Weisbrodt Norman W, Mercer David W, Moore Frederick A
Department of Surgery, The University of Texas Medical School at Houston, Houston, Texas 77030, USA.
J Trauma. 2005 Nov;59(5):1092-8. doi: 10.1097/01.ta.0000188935.66504.00.
We have previously demonstrated that hypertonic saline (HS) resuscitation decreased inflammation and mucosal injury after mesenteric ischemia/reperfusion (I/R). In contrast to I/R cell necrosis, apoptosis provides controlled cell death that minimizes inflammation. We therefore hypothesized that HS resuscitation after mesenteric I/R would induce apoptosis and decrease mucosal injury.
Rats underwent 60 minutes of superior mesenteric artery occlusion (SMAO) and then received no resuscitation or resuscitation with 4 mL/kg of HS, 4 mL/kg of lactated Ringer's (LR) solution (equal volume), or 32 mL/kg of LR solution (equal salt load). Rats were killed at 6 hours of reperfusion, and ileum was harvested for analysis. DNA fragmentation (apoptosis) was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) and mucosal injury by histology (Chiu score 0-5). Caspase-3 (proapoptotic mediator) and Bcl-xL (antiapoptotic mediator) protein expression were analyzed by Western immunoblot.
SMAO with no resuscitation, SMAO with 4 mL/kg of LR, and SMAO with 32 mL/kg of LR increased apoptosis (quantitated by TUNEL) and I/R-induced mucosal injury (quantitated by Chiu score). This was associated with an increase to similar levels in both proapoptotic caspase-3 and antiapoptotic Bcl-xL protein expression. Moreover, SMAO with 4 mL/kg of HS further increased apoptosis but decreased mucosal injury. This was associated with a differential expression of proapoptotic caspase-3 over antiapoptotic Bcl-xL.
HS resuscitation after mesenteric I/R significantly increased ileal mucosal apoptosis while decreasing mucosal injury and may represent a novel mechanism by which HS resuscitation after mesenteric I/R reduces inflammation and imparts protection to the gut.
我们之前已经证明，高渗盐水（HS）复苏可减轻肠系膜缺血/再灌注（I/R）后的炎症和黏膜损伤。与I/R导致的细胞坏死不同，细胞凋亡是一种可控的细胞死亡方式，可将炎症降至最低。因此，我们推测肠系膜I/R后进行HS复苏会诱导细胞凋亡并减轻黏膜损伤。
对大鼠进行60分钟的肠系膜上动脉闭塞（SMAO），然后不进行复苏或分别用4 mL/kg的HS、4 mL/kg的乳酸林格氏液（LR）（等体积）或32 mL/kg的LR溶液（等盐负荷）进行复苏。在再灌注6小时后处死大鼠，采集回肠进行分析。通过末端脱氧核苷酸转移酶介导的dUTP生物素缺口末端标记法（TUNEL）评估DNA片段化（细胞凋亡），通过组织学方法（Chiu评分0 - 5）评估黏膜损伤。通过蛋白质免疫印迹法分析半胱天冬酶-3（促凋亡介质）和Bcl-xL（抗凋亡介质）蛋白表达。
未复苏的SMAO、4 mL/kg LR复苏的SMAO以及32 mL/kg LR复苏的SMAO均增加了细胞凋亡（通过TUNEL定量）和I/R诱导的黏膜损伤（通过Chiu评分定量）。这与促凋亡的半胱天冬酶-3和抗凋亡的Bcl-xL蛋白表达均增加至相似水平有关。此外，4 mL/kg HS复苏的SMAO进一步增加了细胞凋亡，但减轻了黏膜损伤。这与促凋亡的半胱天冬酶-3相对于抗凋亡的Bcl-xL的差异表达有关。
肠系膜I/R后进行HS复苏可显著增加回肠黏膜细胞凋亡，同时减轻黏膜损伤，这可能是肠系膜I/R后HS复苏减轻炎症并对肠道起到保护作用的一种新机制。
