山莨菪碱对失血性休克兔小肠微循环血量及血液酸碱度的影响

目的观察山莨菪碱对失血性休克兔小肠微循环血流量及血液酸碱度变化情况。方法大白兔16只随机分为2组,分别是山莨菪碱治疗组(S组,n=8)和生理盐水对照组(C组,n =8)。复制兔重度失血性休克及复苏的动物模型,在休克期间分别予等容量的山莨菪碱注射液和生理盐水治疗,复苏60 min。观察放血前、放血后10、30、60 min小肠黏膜微循环血流量、动脉平均血压、中心静脉压。在放血前、放血后10、30、60 min取颈动脉、肠系膜上静脉血液少量进行血气分析。结果放血后两组动物休克期小肠黏膜微循环血流量均比放血前明显降低(P<0.05);回输血液后S组动物小肠微循环血流量恢复,与放血前比较差异无统计学意义(P>0.05);C组动物在再灌注10、30、60 min时的微循环血流量明显低于放血前(P<0.05)。在再灌注60 min时S组的颈动脉血pH值、BE值高于C组(P<0.05);而对肠系膜上静脉血,S组在再灌注30、60 min时的pH值高于C组,在再灌注10、30、60 min时的BE值高于C组(P<0.05)。结论山莨菪碱能改善失血性休克时肠黏膜微循环,有利于更快清除肠微循环蓄积的酸性物质。     

缺血后适应在兔急性肠系膜缺血再灌注损伤模型中的作用

目的 观察缺血后适应干预措施能否减轻兔急性肠系膜缺血再灌注损伤.方法 将雄性新西兰兔120只随机分为空白对照(Con)组(仅开腹显露SMA)、缺血再灌注(I/R)组[肠系上动脉(superior mesenteric artery,SMA)缺血30 min后持续灌注120 min]、缺血后适应1(IpostC1)组(SMA缺血30 min后行3个循环的灌注30 s/阻断30 s,再持续灌注117 min)、缺血后适应2(IpostC2)组(SMA缺血30 min后行3个循环的灌注60s/阻断60 s,再持续灌注114 min),每组30只.干预后采集各组兔处理后下腔静脉血及部分肠道组织标本,试剂盒测定血清及肠道组织内丙二醛(MDA)、髓过氧化酶(MPO)水平,HE染色,Chiu 6级评分法观察肠黏膜损伤情况. 结果 与对照组比较,I/R组及IpostC1组、IpostC2组血清及肠道组织中MDA、MPO水平明显增加(P＜0.01),肠黏膜损伤评分明显升高(P＜0.01).与I/R组相比,IpostC1组血清和肠道组织中MDA、MPO水平及肠黏膜损伤评分明显降低(P＜0.01),而IpostC2组血清和肠道组织中MDA、MPO水平及肠黏膜损伤评分无明显降低(P＞0.05).结论 缺血后适应可明显降低兔急性肠系膜缺血再灌注损伤后下腔静脉血和肠道组织中MDA、MPO水平及肠黏膜损伤.     

硫酸镁对兔脊髓缺血再灌注损伤保护作用的研究

目的:探讨硫酸镁对兔脊髓缺血再灌注损伤的保护效果。方法:27只新西兰大白兔,随机分为A组(硫酸镁处理组)、B组(生理盐水)和C组(假手术对照组)。A、B两组参照Tetik方法建立兔脊髓腰骶段缺血模型,比较三组动物不同时间点的体感诱发电位(SEP)、后肢运动功能评分及缺血再灌注后48h的病理学改变。结果:C组SEP没有明显变化,动物均完全康复。缺血30min时B组波形消失,A组波幅降为基线的(29.3±1.9)%。再灌注60min后A组、B组SEP波幅分别渐升致基线的(74.5±2.3)%和(49.2±2.1)%。A组N1、P1波峰潜伏期在缺血30min及再灌注60min时均明显优于B组(P<0.05);再灌注24h和48h后,A组的后肢运动功能评分均显著高于B组(P<0.05);再灌注48h后A组的脊髓前角神经细胞计数显著高于B组(P<0.01)。结论:硫酸镁具有减轻兔脊髓缺血再灌注损伤及保护神经功能的作用。     

卡巴胆碱对烧创伤后肠道功能障碍影响的研究

目的观察肠道内给予卡巴胆碱对兔肠部分缺血再灌注(I/R)损伤及重度烧伤患者肠道功能障碍的影响。方法将50只大白兔制成肠部分I/R损伤模型后,随机分为肠部分I/R损伤组(25只)、卡巴胆碱组[25只,于肠系膜上动脉(SMA)阻断后1h肠内注入3g/L卡巴胆碱(3μg/kg)]；另取25只设为假手术组,仅分离SMA,不阻断；取5只作为正常对照组,不致伤,处死后留取标本待测。检测兔SMA阻断前后及肠道内给予卡巴胆碱后肠黏膜的血流量。各致伤组均在处理后2、4、6、8、24、48、72h留取静脉血测定其血浆二胺氧化酶(DAO)活性及D-乳酸和D-木糖含量。并行葡聚糖蓝排出实验,以检测胃肠道吸收功能。同时选择大面积烧伤[烧伤总面积(84±12)%TBSA]患者8例,在患者肠呜音＜2次/min或腹胀明显时,口服1g/L卡巴胆碱(15μg/kg),观察给药后每分钟肠鸣音次数及腹胀情况。结果SMA阻断后肠部分I/R损伤组肠黏膜血流量为(48±6)PU,较正常对照组[(102±5)PU]明显减少,而肠道内注入卡巴胆碱后1h血流量增至(77±3)PU。肠缺血后肠部分I/R损伤组血浆DAO活性及D-乳酸含量开始升高,处理后24h达峰值[(4．63±0．27)U/ml、(7．9±2．4)mg/L],以后逐渐下降,但仍高于正常对照组[(0．89±0．14)U/ml、(2．0±1．1)mg/L,P＜0．05]。卡巴胆碱组的变化基本同肠部分I/R损伤组,但变化幅度较小；而假手术组则无明显变化(P＞0．05)。在给予D-木糖后2h,肠部分I/R损伤组血浆D-木糖含量显著降低,但处理后6h肠部分I/R损伤组及卡巴胆碱组明显升高,以后逐渐下降；假手术组略有波动。SMA处理后2h肠部分I/R损伤组葡聚糖蓝未见排出,处理后6h其运动距离逐渐增加,但处理后24h其运动距离仍明显短于正常值(P＜0．05),48～72h基本恢复正常；卡巴胆碱组注入葡聚糖蓝后即可见其排出,其运动距离明显增加,处理后6h达峰值(43±6)cm,以后逐渐缩短接近正常(28±3)cm。给药前患者肠呜音较弱(1．6±1．1)次/min,给药后10 min明显增强为(6．9±1．7)次/min,30 min时为(8．3±2．4)次/min,给药后1h患者肠鸣音仍较活跃,为(6．1±1．3)次/min。给药后2h患者腹胀明显减轻,其中有6例患者开始排便。结论肠内给予卡巴胆碱可增加兔肠黏膜血流量,改善其肠道运动、吸收、屏障功能；大面积烧伤患者口服卡巴胆碱,可改善其肠道功能障碍。     

滋养性肠内营养对大鼠肠屏障损伤的改善作用

目的:实验研究不同比例肠内(enteral nutrition,EN)联合肠外营养(parenteral nutrition,PN)对肠缺血/再灌注(ischemia/reperfusion,I/R)肠黏膜损伤的作用。方法:6周SD大鼠夹闭肠系膜上动脉30 min恢复灌注,建立肠I/R模型。放置胃造口管和颈静脉置管,分别用于实施EN和PN。复苏12 h后随机分为6组(每组15只),分别给予不同比例的EN+PN:0+100%、10%+90%、20%+80%、40%+60%、60%+40%、100%+0。术后第6天处死取材,观察各组大鼠肠黏膜上皮和肝脏形态学、血清生化指标。结果:与TPN组相比,20%EN有效减轻大鼠肠I/R后近端空肠上皮和肝脏组织学损伤,增加回肠紧密连接蛋白ZO-1的表达,且显著降低回肠NF-κB-p65蛋白的表达。40%EN显著增加回肠杯状细胞合成与分泌功能,促进黏液层的形成。结论:滋养剂量的EN可有效改善I/R后肠黏膜屏障的损伤,维护屏障功能的完整,促进肠上皮的修复。     

不同生长因子对短肠大鼠残留小肠葡萄糖吸收的影响

目的 比较生长激素(GH)和胰高血糖素样肽-2(GLP-2)对短肠大鼠残留小肠葡萄糖吸收的影响.方法 75%小肠切除大鼠随机分成短肠(SB)组、GH组和CLP-2组.另设1组正常进食大鼠作SB组的对照组.术后1～5 d内自由进食,术后6 d进行在体小肠循环灌流实验测定大鼠回肠单位长度及单位重量的葡萄糖吸收结.结果 GH组和GLP-2组的灌洗段同肠湿重/长度比值及每厘米45 min葡萄糖吸收量均分别显著高于SB组(P<0.05).灌洗段回肠每克湿重葡萄糖吸收率正常组和GH组均显著高于SB组,但SB组和GLP-2组差异无统计学意义(P>0.05).结论 GH和GLP-2都能促进SBS大鼠残留小肠单位长度的葡萄糖吸收,并且两者的促进效能相似.     

硝普钠对大鼠植入小肠黏膜屏障的保护机制

目的:探讨硝普钠(SNP)对移植小肠黏膜屏障的保护机制。方法:以单袖套法构建SD大鼠节段小肠移植模型为研究对象,用硝普钠作为外源性一氧化氮(NO)供体,分成缺血再灌注(I/R)前SNP注射组(A1)、SNP灌注组(A2)、I/R后SNP注射组(A3)与对照组(不用SNP组),观察受体植入肠造口变化情况,并获取植入肠标本,检测黏膜Na -K -ATP酶及细胞凋亡情况,初步分析SNP在不同干预时机对植入小肠黏膜的保护机制。结果:A1、A2组较对照组造口坏死及不良发生率低(P<0.05)、移植肠及受体生存率高(P<0.05)、黏膜组织Na -K -ATP酶含量高(P<0.05)、黏膜上皮及腺上皮细胞凋亡指数降低(P<0.05)。其中A2组以上各指标差异最明显,A3组以上指标均与C组无显著性差异(P>0.05)。结论:利用外源性NO供体SNP进行供肠I/R前预处理与灌注,能够提高大鼠植入肠黏膜屏障的结构和功能完整,而I/R后注射SNP是无效的。     

缺血预处理-后处理对大鼠肠缺血再灌注损伤的影响

目的 评价缺血预处理.后处理对大鼠肠缺血再灌注损伤的影响.方法 清洁级成年雄性SD大鼠40只.体重225～275 g,随机分为5组(n=8):假手术组(S组)仅分离肠系膜上动脉(SMA),不夹闭;肠缺血再灌注组(IIR组)采用夹闭SMA 60 min,再灌注60 min的方法制备肠缺血再灌注损伤模型;缺血预处理组(IPr组)夹闭SMA 10 min,再灌注10 min,余同IIR组;缺血后处理组(IPo 组)夹闭SMA 60 min后,再灌注30 s,缺血30 s,反复3次,再灌注60 min;缺血预处理.后处理组(IPr-IPo组)先行缺血预处理,再行缺血后处理,操作过程同IPr组和IPo组.于再灌注60 min时各组取肠粘膜组织,观察肠粘膜形态并行Chiu评分,检测丙二醛(MDA)含量,超氧化物歧化酶(SOD)及髓过氧化物酶(MPO)活性,同时采集动脉血样检测血浆肿瘤坏死因子α(TNF-α)及白细胞介素6(IL-6)浓度.结果 与S组比较,其余各组Chiu评分、MDA含量、MPO活性、血浆TNF-α与IL-6浓度升高,SOD活性降低(P<0.05).与IIR组比较,IPr组、IPo组及IPr-IPo组Chiu评分、MDA含量、MPO活性、血浆TNF-α和IL-6浓度降低.SOD活性升高(P<0.01).与IPr组和IPo组比较,IPr-IPo组Chiu评分和MDA含量降低,SOD活性升高(P<0.05).IPr组与IPo组各指标比较差异无统计学意义(P>0.05).结论 缺血预处理-后处理可减轻大鼠肠缺血再灌注损伤,较单独应用时效果好.     

肠腔灌注高氧液对缺血-再灌注后肠黏膜屏障损伤的保护作用

目的探讨缺血期经肠腔灌注高氧液对家兔肠缺血-再灌注后肠黏膜屏障损伤的保护作用。方法健康家兔24只,随机均分成三组:缺血-再灌注组(I/R组)、高氧液处理组(HOS组)、假手术对照组(Sham组)。Sham组只开腹游离但不夹闭肠系膜上动脉(SMA),另两组用无损伤动脉夹夹闭SMA1h。HOS组于缺血期以20ml.kg-1.h-1恒速向肠腔灌注高氧液1h,I/R组则以相同的方式灌注等量的生理盐水,松开动脉夹再灌注2h后取标本。光镜下观察各组肠黏膜组织形态学改变,测定肠黏膜组织ATP含量和肠道的氧摄取率(ERO2);定量分析门静脉血中细菌内毒素(ET)含量;检测血清中肿瘤坏死因子α(TNF-α)、乳酸(Lac)水平;观察细菌移位率。结果与Sham组相比,I/R组光镜下肠黏膜损伤严重,肠黏膜组织ATP含量及肠道的ERO2均明显下降,血液中ET含量、Lac和TNF-α水平明显升高(P<0.05或P<0.01),同时出现了广泛的细菌移位;经肠腔灌注高氧液(HOS组)能够明显改善小肠黏膜损伤及上皮细胞形态学改变,显著提高肠黏膜组织ATP含量及ERO2;明显降低血液中ET、Lac和TNF-α水平(P<0.05或P<0.01),同时显著减少肠道细菌移位率(P<0.05)。结论肠腔灌注高氧液能够显著减轻肠缺血-再灌注引起的小肠黏膜屏障功能障碍,是一种安全有效的小肠保护方法。     

不同营养方式对肠道缺血再灌注大鼠肠屏障功能的影响

目的探讨不同营养物质及支持途径对肠道缺血再灌注大鼠肠屏障功能和细菌易位的影响。方法60只雄性SD大鼠建立肠道缺血再灌注模型,随机分成普通肠外营养组(PN),富含谷氨酰胺的肠外营养组(G-PN),普通肠内营养组(EN)及免疫增强型肠内营养组(IEN)。从术后第1天起连续营养支持7d,各组等氮、等热卡。观察肠道形态学、肠道黏膜通透性、肠道细菌易位情况和血浆内毒素水平及肠道免疫功能检测。结果PN组肠黏膜明显萎缩,其绒毛高度、黏膜厚度、隐窝深度及绒毛表面积均显著低于其他各组(P<0.05);其肠黏膜通透性及内毒素值显著高于其他各组(P<0.05),细菌易位率(100%)明显高于其他各组(G-PN组60.0%,EN组33.3%,IEN组20.0%)。PN组CD4 T淋巴细胞和IgA 浆细胞分布显著低于其他各组(P<0.01)。结论EN在维护肠黏膜屏障功能、防止细菌及内毒素易位方面优于PN。免疫增强型EN在维护肠黏膜屏障、改善肠道免疫功能、防止细菌易位方面作用优于普通EN。     

The importance of luminal factors in neomucosal growth

Growing neomucosa on patched intestinal defects has been investigated as a method of expanding the intestinal absorptive area. The purpose of this study was to determine the effect of luminal factors on the rate of growth and function of neomucosa in rabbit ileum. A 2 X 5-cm distal ileal defect was patched with adjacent colon serosa in 10 New Zealand white male rabbits. A similar defect was patched in a bypassed ileal segment in an additional 10 rabbits. Five animals in each group were sacrificed at 4 and 8 weeks for determination of the gross and microscopic growth of neomucosa, glucose uptake, and disaccharidase activity. In addition, tritiated thymidine uptake was measured in neomucosa and incontinuity ileum at the 4-week sacrifice. Grossly, the patched defects were covered in nearly all animals by 4 weeks and coverage was complete at 8 weeks. Microscopically, the mucosa was less well developed in the bypassed group with a mean villous height significantly less than the incontinuity group (139.9 +/- 13.9 microns vs 212.33 +/- 30.3 microns, P less than 0.0005). In vitro uptake of [3H]thymidine was significantly higher in neomucosa in bypassed segments when compared with neomucosa in incontinuity segments (692.5 +/- 347.8 vs 278.0 +/- 134.8, P less than .05, expressed as percentage of normal incontinuity ileum). Glucose uptake was similar in both groups but disaccharidase activity was significantly less in the bypassed group. The increased uptake of [3H]thymidine in neomucosa in the bypassed segment may reflect the histologic immaturity of this tissue with a greater proportion of DNA synthesizing cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Absorption of the urinary constituents from canine ileum

To clarify the mechanism of metabolic changes after using intestinal segments as a urinary tract, absorption of urinary constituents from the ileum was studied in dogs. An isolated distal ileum (30 cm in length) was anastomosed to the urinary bladder in each dog. Although these animals maintained the normal renal function throughout the experimental period, mild acidosis was noticed one month after anastomosis and it became severe after six months. Stagnation of a urine-like solution (artificial urine: AU) in the isolated ileum resulted in an absorption of 66% of the instilled solvent on average during 60 minutes. The average absorption rates of each AU constituent were as follows: sodium 63%, potassium 80%, chloride 83%, phosphorus 68%, magnesium 34%, urea nitrogen 93% creatinine 56%, and ammonia 97%. On the contrary, calcium increased in the stagnated fluid by 21%. In spite of the severe histologic changes in the villi of the ileal mucosa, which became atrophic and flat, no deterioration in the absorptive capacity of the AU constituents was noticed during the six month experimental period. Furosemide administration suppressed the absorption of urinary constituents, especially water and sodium. On the other hand, the absorption of urea nitrogen and ammonia was scarcely affected. Perfusion of the isolated ileum with AU (0.5 ml/min) for 60 minutes resulted in an absorption of 59% of the solvent and 50 to 86% of each constituent. The rate of absorption was reduced after increment of the perfusion rate. In conclusion, the absorption of urinary constituents occurs rapidly and significantly. The absorptive capacity remains longer regardless the severity of histological changes of the ileal mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)     

The use of silver nitrate for chemical de-epithelialization and urothelialization of intestine in a rabbit model of augmentation cystoplasty

Urinary tract reconstruction using bowel segments can result in complications such as electrolyte abnormalities, infections, stones and cancer. Intestinal mucosa is the primary site responsible for these complications. De-epithelialization of the mucosa and subsequent urothelialization might alleviate these problems. We recently reported our success in de-epithelialization and subsequent uroepithelialization of intestinal segments using 10 g/100 ml AgNO₃ solution in a rat model of augmentation. In this study, chemical de-epithelialization of a colonic segment was attempted using 10 g/100 ml AgNO₃ solution in a rabbit model of augmentation. Sigmoid cystoplasty was performed in 20 male New Zealand rabbits using a 6 cm patch of sigmoid colon. There were two groups, including one group of five rabbits (control, group 1) that underwent augmentation alone, while another group (15 rabbits, treatment group or group 2) was treated with 10g/100 ml AgNO₃ solution before augmentation. Control rabbits were killed at the week 8 of experimentation. Treatment rabbits were killed at 2-, 4-, 6- and 8-week intervals. Immediately before augmentation and at the end of the 8 week experimental period each rabbit underwent cystometry. De-epithelialization of the bowel epithelium without urothelialization was apparent in the treatment rabbits killed at 2 and 4 weeks. Histological analysis revealed almost complete urothelialization of the augmented sections treated with 10 g/100 ml AgNO₃ solution at the end of the 6 and 8 week of experimental periods. The preoperative and postoperative bladder capacities increased substantially in all groups. There was no obvious histologic difference in the amount of collagen present in the augmented tissues in any of the experimental groups. The present study confirmed that the treatment of intestinal segments with 10g/100 ml AgNO₃ solution led to chemical de-epithelialization and urothelialization of the augmented segments. This procedure could, theoretically, have applications to human surgery.     

Effect of intestinal location on growth and function of neomucosa

Growing intestinal neomucosa in patched intestinal defects has been investigated as a means of permanently increasing the absorptive capacity in the short bowel syndrome. Several factors, including luminal contents, appear to affect the growth and function of the neomucosa. The purpose of this study was to compare function and rate of growth of neomucosa in patched defects of the jejunum and ileum. In both the jejunum and ileum of 11 New Zealand white male rabbits 2 X 5-cm patched intestinal defects were created using the serosal surface of adjacent colon. The animals were sacrificed at 4 weeks (n = 6) and 8 weeks (n = 5) after operation. Grossly there was more complete coverage of the defect by neomucosa in the ileum at both 4 and 8 weeks (99.1 +/- 1.1% vs 92.6 +/- 6.3% overall P less than 0.005). Villous height of the ileal neomucosa was similar to normal mucosa at 8 weeks (209 +/- 21 vs 244 +/- 18 m) but was significantly less in the jejunum (209 +/- 16 vs 273 +/- 16 m, P less than 0.005). Glucose uptake by neomucosa was greater in the ileum than the jejunum (3.34 +/- .84 vs 2.39 +/- .46 nmole/min/mg, P less than 0.05) but was similar to normal mucosa at both sites. Disaccharidase activity (lactase, sucrase, and maltase) was similar in both jejunum and ileum but was significantly less in ileal neomucosa than in normal mucosa (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)     

Luminal contact with University of Wisconsin solution improves human small bowel preservation

AIM: Under clinical conditions small bowel mucosa is stored without any contact between the mucosa and the preservation solution. We evaluated the impact of luminal contact with University of Wisconsin solution (UW) on the structural quality of small bowel preservation. METHODS: Segments of ileum harvested from stable multi-organ donors were flushed with UW. For each donor, ileal segments were placed in UW without any contact between the mucosa and the preservation solution (group A), as is practiced in clinical conditions. Adjacent segments were cut on their antimesenteric side and placed in UW so that their mucosa was widely in contact with the solution (group B). The grafts preserved in ice were removed from the preservation fluid at different times (0, 3, 6, or 12 hours). Tissues were studied by optical microscopy after H&E staining of formalin-fixed, paraffin-embedded specimens. A median histologic score was calculated after examination of three random slides for each ileal segment per time point. Comparisons were performed between tissues of groups A and B from the same donor. RESULTS: Control (0h) specimens showed normal histology. As early as 3 hours of preservation, group A tissues showed detachment of the villar epithelium. At 6 and 12 hours of preservation in this group further tissue alteration were obvious with complete epithelial detachment from the basal membrane of the villi. The histologic score of the segments preserved by luminal contact with UW was always significantly higher than the controls from the same donor. CONCLUSION: Luminal contact between the mucosa of intestinal grafts and UW improves the quality of human small bowel preservation.     

Determination of the time required for appropriate chemical de-epithelialization of an ileal segment for cystoplasty: an animal model

Another group of authors from Iran attempted experimentally to determine the required time for the appropriate enzymatic treatment of the ideal segment to complete de-epithelialization, thus reducing its absorptive function. They found that 25 min of enzymatic treatment of the ideal segment was adequate for this, and that it was recommended from their experimental study for cystoplasty. OBJECTIVES: To determine the time required for the appropriate enzymatic treatment of an ileal segment to de-epithelialize its mucosa and to reduce its absorptive function for cystoplasty in dogs. MATERIALS AND METHODS: Twenty-one adult female Persian mixed-breed dogs were divided into seven equal groups: group 1 (negative control group) had no ileocystoplasty; group 2 (positive control group) had a routine ileocystoplasty with no enzymatic treatment of the ileal segment; and groups 3-7 had an ileocystoplasty with 5, 10, 15, 20 or 25 min, respectively, of enzymatic treatment of the ileal segment with collagenase and trypsin. The seven groups were then compared for haematological, biochemical and histological changes, and glucose reabsorption assessed using a glucose-absorption test. RESULTS: No dogs showed any signs of metabolic disturbances, biochemical and haematological changes. There were significant differences in blood glucose level (BGL) for the groups at different times after the glucose-absorption test, but a pair-wise comparison showed significant differences in BGL between group 1 and the other groups, except group 7. The degree of histopathological change was associated with the duration of enzymatic treatment, in that changes were more prominent in group 7. There was no shrinkage or collagen deposition. CONCLUSIONS: In these conditions, 25 min of enzymatic treatment of the ileal segment is sufficient to remove the absorptive function of the augmented bladder, and is recommended for cystoplasty in dogs.     

生脉注射液对肠粘膜再灌注损伤保护作用机制的实验研究

目的探讨生脉注射液(SM)对休克再灌注期间肠粘膜的保护作用及机制.方法利用兔休克复苏模型,21只家兔随机分为SM组(A组)、单纯复苏组(B组)和对照组组(C组).分别于实验前(S0)、休克1h(S1)、及再灌注1h(R1)、3h(R3)观察乙状结肠粘膜内pH(pHi)、肠氧摄取率(ERO2)、肠粘膜一氧化氮(NO)、丙二醛(MDA)及钙(Ca2+)含量、肠粘膜病理病理形态学变化.结果A组R1和R3时肠pHi及肠ERO2明显高于B组相应值,肠粘膜NO、MDA及Ca2+含量低于B组(均为P＜0.05),而B组复苏期间肠pHi维持在S1时的低水平状态,肠ERO2显著降低,肠粘膜NO、MDA及Ca2+含量均明显高于A组和C组;光镜下肠粘膜损伤A组显著轻于B组且病理分级与肠pHi负相关(r=-0.841,P＜0.05).结论SM对休克再灌注期间肠粘膜的保护作用机制为增加肠粘膜灌注及氧合、抑制肠粘膜NO活性、清除氧自由基及减轻钙超载.     

A new model for human intestinal preservation: comparison of University of Wisconsin and Celsior preservation solutions

AIM: We compared University of Wisconsin (UW) and Celsior preservation solutions using a new model of human intestinal preservation that mimics the clinical conditions of small bowel procurement. METHODS: Intestinal grafts were harvested from four multiorgan donors. After classic warm dissection for organ procurement, an ileal segment of 50 cm was immediately flushed with Celsior. After the perfusion of the abdominal organs with UW, a second segment of adjacent ileum was harvested. The two intestinal grafts were then divided into segments by stapling, before immersion into the corresponding preservation solution (Celsior or UW) for 0-, 6-, 12-, or 24-hour incubation at 4 degrees C. A histological score was graded after blinded examination of three random specimens within each ileal graft for each duration of preservation. RESULTS: Control specimens showed normal histology. After 6 hours of preservation, most villi showed complete epithelial detachment although the crypts appeared intact. After 12 hours of preservation, a larger proportion of the villi showed extensive epithelial sloughing. After 24 hours, the damage involved the entire mucosa with the crypt epithelium largely detached from the basal membrane. No statistical difference in histological score was observed between the two preservation solutions. CONCLUSION: This study showed severe histological alterations of graft mucosa after short periods of preservation by UW or Celsior solutions. This model may be useful to evaluate improvements in the quality of preservation of human intestinal transplants.     

Protective effects of ischemic postconditioning on intestinal mucosa barrier function in rabbits with crush injury of hind limb: an experimental study

Objective: To explore the protective effects of two types of ischemic postconditioning (IP) on intestinal mucosa barrier in rabbits with crush injury of the hind limb.Methods: This study was conducted between August and December 2008 in the Department of Trauma Surgery,Daping Hospital, Third Military Medical University,Chongqing, China. The model of crush injury to the hind limb of rabbits was firstly developed by a 25 kg object with the right hind limbs fixed by wooden splints, and then two types of IP were established, including occluding/opening the common iliac artery and vein alternatively (traditional IP, IP A) and binding/loosening the proximum of the injured hind limb alternatively (modified IP, IP B). Thirty-six male New Zealand white rabbits were randomly divided into three groups: IP A group, IP B group and control group, with 12rabbits in each group. The serum levels of diamine oxidase (DAO) and intestinal fatty acid-binding protein (Ⅰ-FABP)were detected at 2, 6, 12 and 24 hours after injury. Pathological changes of ileum were examined at 24 hours alter injury.Results: The serum levels of I-FABP at 2, 6, 12 and 24hours after injury in both IP A and IP B groups had a significant decrease, compared with control group. DAO levels also showed the same change trend at 2 and 6 hours after injury, but showed no significant difference between two IP groups. No difference in pathological changes of ileum was found among the three groups.Conclusions: IP can protect intestinal mucosa barrier function on the model of hind limb crush injury in rabbits.Meanwhile the modified IP B shows the same protection as the traditional IP A, and is worth applying in clinic.     

Mucosal damage and recovery of the intestine after prolonged preservation and transplantation in dogs

BACKGROUND: Although much is known about the mucosal damage that occurs after intestinal warm ischemia and reperfusion and its recovery, little is known about the effect of cold preservation and transplantation on the mucosa. We studied the electrophysiological, biochemical, and histological changes of the intestinal mucosa after preservation for 24 hr and subsequent transplantation. METHODS: The small intestines from adult mongrel dogs were harvested. The intestines were orthotopically autotransplanted immediately (control group) or after preservation for 24 hr (preservation group). Jejunal and ileal tissues were taken before harvesting, at the end of preservation, 1 hr after reperfusion, and on postoperative days 3, 7, 14, and 28. The Ussing chamber method was used to study the electrophysiologic changes. Tissue maltase, diamine oxidase, and ornithine decarboxylase were measured. A histological analysis was also performed. RESULTS: Control group grafts showed no evident deterioration in electrophysiology, biochemistry, or morphology. In contrast, preservation group grafts exhibited electrophysiological and biochemical degradation, complete denudation of the villi, and crypt injury (especially in the ileum) after reperfusion. Electrophysiologic function and the mucosa biochemical marker recovered within 3 days in the jejunum and within 7-14 days in the ileum; however, histological recovery of mucosal injury required 28 days in the jejunum and more than 28 days in the ileum. CONCLUSIONS: Our study showed that despite severe destruction of mucosal integrity by prolonged preservation and transplantation, the intestinal mucosa has an enormous regenerative capacity. Our study also showed that regeneration was more pronounced in the jejunum than in the ileum.