Chang Jian-Xing, Chen Shuang, Ma Li-Ping, Jiang Long-Yuan, Chen Jian-Wen, Chang Rui-Ming, Wen Li-Qiang, Wu Wei, Jiang Zhi-Peng, Huang Zi-Tong
The Second Affiliated Hospital, Sun Yat-Sen University, 107# West Yanjiang Road, Guangzhou, 510120, Guangdong Province, China.
World J Gastroenterol. 2005 Sep 21;11(35):5485-91. doi: 10.3748/wjg.v11.i35.5485.
To investigate the functional, morphological changes of the gut barrier during the restitution process after hemorrhagic shock, and the regional differences of the large intestine and small intestine in response to ischemia/reperfusion injury.
Forty-seven Sprague-Dawley rats with body weight of 250-300 g were divided into two groups: control group (sham shock n = 5) and experimental group (n = 42). Experimental group was further divided into six groups (n = 7 each) according to different time points after the hemorrhagic shock, including 0(th) h group, 1st h group, 3rd h group, 6th h group, 12th h group and 24th h group. All the rats were gavaged with 2 mL of suspension of lactulose (L) (100 mg/2 mL) and mannitol (M) (50 mg/each) at the beginning and then an experimental rat model of hemorrhagic shock was set up. The specimens from jejunum, ileum and colon tissues and the blood samples from the portal vein were taken at 0, 1, 3, 6, 12 and 24 h after shock resuscitation, respectively. The morphological changes of the intestinal mucosa, including the histology of intestinal mucosa, the thickness of mucosa, the height of villi, the index of mucosal damage and the numbers of goblet cells, were determined by light microscope and/or electron microscope. The concentrations of the bacterial endotoxin lipopolysaccharides (LPS) from the portal vein blood, which reflected the gut barrier function, were examined by using Limulus test. At the same time point, to evaluate intestinal permeability, all urine was collected and the concentrations of the metabolically inactive markers such as L and M in urine were measured by using GC-9A gas chromatographic instrument.
After the hemorrhagic shock, the mucosal epithelial injury was obvious in small intestine even at the 0(th) h, and it became more serious at the 1st and the 3rd h. The tissue restitution was also found after 3 h, though the injury was still serious. Most of the injured mucosal restitution was established after 6 h and completed in 24 h. Two distinct models of cell death-apoptosis and necrosis-were involved in the destruction of rat intestinal epithelial cells. The number of goblet cells on intestinal mucosa was reduced significantly from 0 to 24 h (the number from 243+/-13 to 157+/-9 for ileum, 310+/-19 to 248+/-18 for colon; r = -0.910 and -0.437 respectively, all P<0.001), which was the same with the large intestine, but the grade of injury was lighter with the values of mucosal damage index in 3 h for jejunum, ileum, and colon being 2.8, 2.6, 1.2, respectively. The mucosal thickness and the height of villi in jejunum and ileum diminished in 1 h (the average height decreased from 309+/-24 to 204+/-23 microm and 271+/-31 to 231+/-28 microm, r = -0.758 and -0.659, all P<0.001; the thickness from 547+/-23 to 418+/-28 microm and 483+/-45 to 364+/-35 microm, r = -0.898 and -0.829, all P<0.001), but there was no statistical difference in the colon (F = 0.296, P = 0.934). Compared with control group, the urine L/M ratio and the blood LPS concentration in the experimental groups raised significantly, reaching the peak in 3-6 h (L/M: control vs 3 h vs 6 h was 0.029+/-0.09 vs 0.063+/-0.012 vs 0.078+/-0.021, r = -0.786, P<0.001; LPS: control vs 3 h vs 6 h was 0.09+/-0.021 vs 0.063+/-0.012 vs 0.25+/-0.023, r = -0.623, P<0.001), and it kept increasing in 24 h.
The gut barrier of the rats was seriously damaged at the early phase of ischemic reperfusion injury after hemorrhagic shock, which included the injury and atrophy in intestinal mucosa and the increasing of intestinal permeability. Simultaneously, the intestinal mucosa also showed its great repairing potentiality, such as the improvement of the intestinal permeability and the recovery of the morphology at different phases after ischemic reperfusion injury. The restitution of gut barrier function was obviously slower than that of the morphology and there was no direct correlation between them. Compared with the small intestine, the large intestine had stronger potentiality against injury. The reduction of the amount of intestinal goblet cells by injury did not influence the ability of intestinal mucosal restitution at a certain extent and it appeared to be intimately involved in the restitution of the epithelium.
探讨失血性休克后肠屏障在修复过程中的功能和形态学变化，以及大肠和小肠对缺血/再灌注损伤反应的区域差异。
将47只体重250 - 300 g的Sprague-Dawley大鼠分为两组：对照组（假休克，n = 5）和实验组（n = 42）。实验组根据失血性休克后的不同时间点进一步分为六组（每组n = 7），包括0小时组、1小时组、3小时组、6小时组、12小时组和24小时组。所有大鼠在开始时均灌胃2 mL乳果糖（L）（100 mg/2 mL）和甘露醇（M）（50 mg/只）的混悬液，然后建立失血性休克实验大鼠模型。分别在休克复苏后0、1、3、6、12和24小时采集空肠、回肠和结肠组织标本以及门静脉血样。通过光学显微镜和/或电子显微镜观察肠黏膜的形态学变化，包括肠黏膜组织学、黏膜厚度、绒毛高度、黏膜损伤指数和杯状细胞数量。采用鲎试剂法检测门静脉血中反映肠屏障功能的细菌内毒素脂多糖（LPS）浓度。在同一时间点，为评估肠道通透性，收集所有尿液，并用GC - 9A气相色谱仪测定尿液中L和M等代谢惰性标志物的浓度。
失血性休克后，即使在0小时小肠黏膜上皮损伤就很明显，在1小时和3小时时损伤更严重。3小时后也发现组织修复，尽管损伤仍然严重。大多数受损黏膜在6小时后开始修复，并在24小时内完成。大鼠肠上皮细胞的破坏涉及两种不同的细胞死亡模式——凋亡和坏死。肠黏膜上杯状细胞数量从0小时到24小时显著减少（回肠从243±13减少到157±9，结肠从310±19减少到248±18；r分别为 - 0.910和 - 0.437，均P<0.001），大肠情况相同，但损伤程度较轻，空肠、回肠和结肠在3小时时的黏膜损伤指数分别为2.8、2.6、1.2。空肠和回肠的黏膜厚度和绒毛高度在1小时时减小（平均高度从309±24微米降至204±23微米，从271±31微米降至231±28微米，r分别为 - 0.758和 - 0.659，均P<0.001；厚度从547±23微米降至418±28微米，从483±45微米降至364±35微米，r分别为 - 0.898和 - 0.829，均P<0.001），但结肠无统计学差异（F = 0.296，P = 0.934）。与对照组相比，实验组尿液L/M比值和血LPS浓度显著升高，在3 - 6小时达到峰值（L/M：对照组 vs 3小时组 vs 6小时组分别为0.029±0.09 vs 0.063±0.012 vs 0.078±0.021，r = - 0.786，P<0.001；LPS：对照组 vs 3小时组 vs 6小时组分别为0.09±0.021 vs 0.063±专业翻译，请确认，谢谢！012 vs 0.25±0.023，r = - 0.623，P<0.001），并在24小时内持续升高。
失血性休克后缺血再灌注损伤早期大鼠肠屏障严重受损，包括肠黏膜损伤和萎缩以及肠道通透性增加。同时，肠黏膜也显示出强大的修复潜力，如缺血再灌注损伤后不同阶段肠道通透性的改善和形态的恢复。肠屏障功能的恢复明显慢于形态恢复，且二者无直接相关性。与小肠相比，大肠具有更强的抗损伤潜力。损伤导致的肠杯状细胞数量减少在一定程度上不影响肠黏膜修复能力，且似乎与上皮修复密切相关。
