Effect of bowel rehabilitative therapy on structural adaptation of remnant small intestine: animal experiment

AIM: To investigate the individual and the combined effects of glutamine, dietary fiber, and growth hormone on the structural adaptation of the remnant small bowel. METHODS: Forty-two adult male Sprague-Dawley rats underwent 85% mid-small bowel resection and received total parenteral nutrition (TPN) support during the first three postoperational days.From the 4th postoperational day, animals were randomly assigned to receive 7 different treatments for 8 days: TPNcon group, receiving TPN and enteral 20 g x L(-1) glycine perfusion; TPN+Gln group, receiving TPN and enteral 20 g x L(-1) glutamine perfusion; ENcon group, receiving enteral nutrition (EN) fortified with 20 g x L(-1) glycine; EN+Gln group, enteral nutrition fortified with 20 g x L(-1) glutamine; EN+Fib group, enteral nutrition and 2 g x d(-1) oral soybean fiber; EN+GH group, enteral nutrition and subcutaneous growth hormone (GH) (0.3 IU) injection twice daily; and ENint group, glutamine-enriched EN, oral soybean fiber, and subcutaneous GH injection. RESULTS: Enteral glutamine perfusion during TPN increased the small intestinal villus height (jejunal villus height 250 microm +/- 29 microm in TPNcon vs 330 microm +/- 54 microm in TPN+Gln, ileal villus height 260 microm +/- 28 microm in TPNcon vs 330 microm +/- 22 microm in TPN+Gln, P【0.05) and mucosa thickness (jejunal mucosa thickness 360 microm +/- 32 microm in TPNcon vs 460 microm +/- 65 microm in TPN+Gln, ileal mucosa thickness 400 microm +/- 25 microm in TPNcon vs 490 microm +/- 11 microm in TPN+Gln,P【 0.05) in comparison with the TPNcon group. Either fiber supplementation or GH administration improved body mass gain (end body weight 270 g +/- 3.6g in EN+Fib, 265.7 g +/- 3.3 g in EN+GH, vs 257 g +/- 3.3 g in ENcon, P【 0.05), elevated plasma insulin-like growth factor (IGF-I) level (880 microg x L(-1). 52 microg x L-(-1) in EN+Fib,1200 microg x L(-1). 96 microg x L-(-1) in EN +/- GH, vs 620 microg x L(-1).43 microg x L-(-1) in ENcon, P【 0.05), and increased the villus height (jejunum 560 microm +/- 44 microm in EN +/- Fib, 530 microm +/- 30 microm in EN +/- GH, vs 450 microm +/- 44 microm in ENcon, ileum 400 microm +/- 30 microm in EN+Fib, P【0.05) and the mucosa thickness (jejunum 740 microm +/- 66 microm in EN +/- Fib, 705 microm +/- 27 microm in EN +/- GH, vs 608 microm +/- 58 microm in ENcon, ileum 570 microm +/- 27 microm in EN +/- Fib, 560 microm +/- 56 microm in remnant jejunum and ileum. Glutamine-enriched EN produced little effect in body mass, plasma IGF-I level, and remnant small bowel mucosal structure. The ENint group had greater body mass (280 g +/- 2.2g), plasma IGF-I level (1450 microg x L(-1). 137 microg x L-(-1)), and villus height (jejunum 620 microm +/- 56 microm, ileum 450 microm +/- 31 microm) and mucosal thickness (jejunum 800 microm +/- 52 microm, ileum 633 microm +/- 33 microm) than those in ENcon, EN+Gln (jejunum villus height and mucosa thickness 450 microm +/- 47 microm and 610 +/- 63 microm, ileum villus height and mucosa thickness 330 microm +/- 39 microm and 500 microm +/- 52 microm), EN+GH groups (P【0.05), and than those in EN+Fib group although no statistical significance was attained. CONCLUSION: Both dietary fiber and GH when used separately can enhance the postresectional small bowel structural adaptation. Simultaneous use of these two gut-trophic factors can produce synergistic effects on small bowel structural adaptation. Enteral glutamine perfusion is beneficial in preserving small bowel mucosal structure during TPN, but has little beneficial effect during EN.

Animal models of ex vivo lung perfusion as a platform for transplantation research

Ex vivo lung perfusion(EVLP) is a powerful experimental model for isolated lung research. EVLP allows for the lungs to be manipulated and characterized in an external environment so that the effect of specific ventilation/perfusion variables can be studied independent of other confounding physiologic contributions. At the same time,EVLP allows for normal organ level function and real-time monitoring of pulmonary physiology and mechanics. As a result,this technique provides uniqueadvantages over in vivo and in vitro models. Small and large animal models of EVLP have been developed and each of these models has their strengths and weaknesses. In this manuscript,we provide insight into the relative strengths of each model and describe how the development of advanced EVLP protocols is leading to a novel experimental platform that can be used to answer critical questions in pulmonary physiology and transplant medicine.

Establishment and improvement of model of vascularized heart-thymus composite transplantation in rats

Objective To establish and improve the model of heart-thymus composite transplantation.Methods Vascularized both lobes of the thymus is transplanted heterotopically with the heart as a composite graft in rats.This technique was developed and assessed,and viability of the grafts was evaluated histologically.Results Donor operation costed 38.5±3.52 min,vascular anastomosis costed 25.0±3.28 min,operating successful rate was 90%,acute rejection was observed in SD-Wistar group,viable thymus with normal microarchitecture was maintained in Wistar-Wistar group.Conclusions The improved novel technique for combined heart-thymus transplantation is a valuable method for study of the role of thymus in transplantation immunity.

A New Carotid Artery Transplantation Model of Rats

To establish a murine carotid artery transplantation model for the study of the chronic rejection, 80 rats were divided into two groups, an allotransplant （ACI-Lewis） group and an isotransplant （Lewis-Lewis） group （control group）. The donor carotid artery and the recipient carotid artery were anastomosed by using a polyethylene cuff （internal diameter： 0.7 mm, length： 3 mm）.The pathological changes of carotid artery transplant were observed 14, 28 and 56 days after the transplantation. The results showed that the model was successfully established in 95% of the animals. The chronic rejection-associated arteriosclerosis was induced 28 days after the transplantation. The new chronic rejection model of carotid artery by using cuff technique caused fewer traumas and was easy to make. The pathological changes of the transplant mimicked the chronic rejection-associated arteriosclerosis found in human transplant.

Visceral hypersensitivity and altered colonic motility after subsidence of inflammation in a rat model of colitis

AIM:Irritable bowel syndrome(IBS)is a functional bowel disorder characterized by visceral hypersensitivity and altered bowel motility.There is increasing evidence suggesting the role of inflammation in the pathogenesis of IBS,which addresses the possibility that formerly established rat model of colitis could be used as an IBS model after the inflammation subsided. METHODS:Colitis was induced by intracolonic instillation of 4% acetic acid in male Sprague-Dawley rats.The extent of inflammation was assessed by histological examination and myeloperoxidase(MPO)activity assay.After subsidence of colitis,the rats were subjected to rectal distension and restraint stress,then the abdominal withdrawal reflex and the number of stress-induced fecal output were measured, respectively. RESULTS:At 2 days post-induction of colitis,the colon showed characteristic inflammatory changes in histology and 8-fold increase in MPO activity.At 7 days post-induction of colitis,the histological features and MPO activity returned to normal.The rats at 7 days post-induction of colitis showed hypersensitive response to rectal distension without an accompaning change in rectal compliance,and defecated more stools than control animals when under stress.CONCLUSION: These results concur largely with the characteristic features of IBS, visceral hypersensitivity and altered defecation pattern in the absence of detectable disease, suggesting that this animal model is a methodologically convenient and useful model for studying a subset of IBS.

Biliary tract injury caused by different relative warm ischemia time in liver transplantation in rats

BACKGROUND: There is a controversy over the degree of liver and biliary injury caused by the period of secondary warm ischemia. A liver autotransplantation model was adopted because it excludes the effects of infection and immunological rejection on bile duct injury. This study was undertaken to assess biliary tract injury caused by relative warm ischemia (secondary warm ischemia time in the biliary tract) and reperfusion. METHODS: One hundred and two rats were randomly divided into 5 groups: group I (control); groups 11 to V, relative warm ischemia times of 0 minute, 30 minutes, I hour and 2 hours. In addition to the levels of serum alkaline phosphatase, and total bilirubin, pathomorphology assessment and TUNEL assay were performed to evaluate biliary tract damage. RESULTS: Under the conditions that there were no significant differences in warm ischemia time, cold perfusion time and anhepatic phase, group comparisons showed statistically significant differences. The least injury occurred in group H (portal vein and hepatic artery reperfused simultaneously) but the most severe injury occurred in group V (biliary tract relative warm ischemia time 2 hours). CONCLUSIONS: Relative warm ischemia is one of the factors that result in bile duct injury, and the relationship between relative warm ischemia time the bile injury degree is time-dependent. Simultaneous arterial and portal reperfusion is the best choice to avoid the bile duct injury caused by relative warm ischemia. (Hepatobiliary Pancreat Dis Int 2009; 8: 247-254)

Comprehensive and innovative techniques for livertransplantation in rats: A surgical guide

AIM: To investigate our learning curves of orthotopic liver transplantation (OLT) in rats and the most important factor for successful surgery. METHODS: We describe the surgical procedures for our rat OLT model, and determined the operator learning curves. The various factors that contributed to successful surgery were determined. The most important surgical factors were evaluated between successful and unsuccessful surgeries.RESULTS: Learning curve data indicated that 50 cases were required for operator training to start a study. Operative time, blood loss, warm ischemic time, anhepatic phase, unstable systemic hemodynamic state, and body temperature after surgery significantly affected surgery success by univariate analysis, while the anhepatic phase was the most critical factor for success by multivariate analysis. CONCLUSION: OLT in rats is the only liver transplantation model that provides clinically relevant and reliable results. Shortened anhepatic phase is key to success in this model.

Improved two-cuff technique for orthotopic liver transplantation in rat

BACKGROUND: The first orthotopic liver transplantatio in rat (ROLT) was reported by Lee in 1973. Kamada inno vatively applied cuff technique to ROLT in 1979. However the operative procedures were highly demanding and th operative mortality was relatively high. The purpose of thi study was to improve the model of ROLT, simplify opera tive procedures, and enhance the successful rate of opera tion. METHODS: Orthotopic liver transplantation was per formed in 160 Wistar rats by improved two-cuff technique The portal vein between donor and recipient was anasto mosed with the cuff technique. The same method was use to anastomose the infrahepatic vena cava. The suprahepati vena cava and the hepatic artery were anastomosed by m crovascular suturing and the bile duct was anastomosed en to end by a Teflon catheter. RESULTS: The average time for donor operation, graf preparation and anhepatic phase was 31 minutes, 14 mi nutes and 13 minutes, respectively. The anastomosis tim for the suprahepatic vena cava, portal vein, infrahepatic ve na cava, hepatic artery and bile duct was 7 minutes, 2 mi nutes, 2 minutes, 8 minutes and 1 minute, respectively The main causes for operative mortality were pneumotho rax, anesthesia, air embolism and massive bleeding, an the successful rate of operation was 92.5%. The causes fo death after operation were stoma bleeding, infection, b liary obstruction and graft failure. CONCLUSION: The improved two-cuff technique can re duce operative mortality, enhance survival rate, and serv as an ideal method for the establishment of animal model o ROLT.

High incidence of biliary complications in rat liver transplantation:Can we avoid it?

MM： To investigate how to reduce the incidence of biliary complications in rat orthotopic liver transplantation. METHODS： A total of 165 male Wistar rats were ran- domly divided into three groups： Group A, orthotropic liver transplantation with modified ＂two-cuff＂ technique; Group B, bile duct was cut and reconstructed without transplantation; and Group C, only laparotomy was performed. Based on the approaches used for biliary reconstruction, Group A was divided into two sub-groups： A1 （n = 30）, duct-duct reconstruction, and A2 （n = 30）, duct-duodenum reconstruction. To study the influence of artery reconstruction on bile duct complication, Group B was divided into four sub-groups： B1 （n = 10）, duct-duct reconstruction with hepatic artery ligation, B2 （n = 10）, duct-duct reconstruction without hepatic artery ligation, B3 （n = 10）, duct-duodenum reconstruction with hepatic artery ligation, and B4 （n = 10）, duct-duodenum recon- struction without hepatic artery ligation. The samples were harvested 14 d after operation or at the time when significant biliary complication was found. RESULTS： In Group A, the anhepatic phase was 13.7 ＋ 1.06 min, and cold ischemia time was 50.5 ＋ 8.6 min. There was no significant difference between A1 and A2 in the operation duration. The time for biliary reconstruction was almost the same among all groups. The success rate for transplantation was 98.3% （59/60）. Significant differ- ences were found in the incidence of biliary complications in Groups A （41.7%）, B （27.5%） and C （0%）. A2 was more likely to have biliary complications than A1 （50% vs 33.3%）. B3 had the highest incidence of biliary complica- tions in Group B. CONCLUSION： Biliary complications are almost in- evitable using the classical ＂two cuff＂ techniques, and duct-duodenum reconstruction is not an ideal option in rat orthotopic liver transplantation.

高频超声在构建SD大鼠皮下移植性乳腺癌模型中的应用

目的:应用MADB-106大鼠乳腺癌细胞悬液皮下移植法建立SD大鼠乳腺癌移植性肿瘤动物模型,并使用高频超声监测肿瘤生长情况。方法:选取7~8周龄雌性SD乳鼠16只,将处于对数生长期的MADB-106大鼠乳腺癌细胞悬液于大鼠腹股沟皮下接种,应用高频超声观察成瘤率、肿块大小、血供情况及其它声像图特征。结果:SD大鼠接种成功率为100%,死亡2只,剩余14只生长良好;超声检查肿块为类圆形,内部低回声且稍不均匀,边界尚清,后方回声衰减,彩色多普勒扫查肿块内部及周边可见较丰富血流信号;3周后切除瘤体组织,大体观肿块成灰白色,多呈椭圆形,部分边缘呈分叶状改变,肿瘤血管较丰富,镜下可见肿瘤细胞大小形状各异,核大深染,异型性明显。结论:通过MADB-106大鼠乳腺癌细胞接种于雌性SD大鼠腹股沟皮下,成功建立了大鼠乳腺癌移植性肿瘤动物模型。高频超声技术可以在SD大鼠乳腺癌皮下成瘤过程中对肿物的大小、形态、边界、内部回声及血流等生物学情况进行动态检测,是观察和评价瘤体动态变化过程的重要技术手段。

Epidermal growth factor upregulates serotonin transporter and its association with visceral hypersensitivity in irritable bowel syndrome

AIM: To investigate the role of epidermal growth factor (EGF) in visceral hypersensitivity and its effect on the serotonin transporter (SERT).

电针足三里对肠易激综合征模型大鼠结肠慢波与整体自主神经平衡性的调控作用

目的观察单独电针足三里穴对肠易激综合征(IBS)模型大鼠结肠慢波放电与整体自主神经平衡性的调节作用,进一步了解单刺足三里穴治疗IBS的效应和机制。方法将36只雄性大鼠随机分为对照组、模型组、电针组,造模后每组选用7只。模型组、电针组大鼠采用避水应激法制作IBS疾病模型。电针组取双侧足三里,连续电针治疗14天,模型组和对照组仅每天在相同时间内进行抓取、固定,不做电针治疗。麻醉状态下记录心电图,记录心率的低频信号(LF)、高频信号(HF),并记录结肠电信号,均使用Powerlab数据采集分析系统进行记录。结果与对照组比较,模型组大鼠结肠慢波频率明显降低(P<0.05);与模型组比较,电针组大鼠结肠慢波频率升高(P<0.05)。与对照组比较,模型组大鼠的LF、LF/HF明显升高(P<0.05),HF明显降低(P<0.05);与模型组比较,电针组大鼠LF、LF/HF均明显降低(P<0.05),HF虽有升高趋势,但比较差异无统计学意义(P>0.05)。结论单独电针足三里穴对IBS模型大鼠的结肠运动功能可起到明显的改善作用,这一作用可能与改善了自主神经系统的平衡性有关。

功能性肠病大鼠模型两种造模方法的比较

目的比较功能性肠病大鼠模型两种造模方法。方法SPF级雄性SD大鼠30只,随机分为3组:正常组、模型Ⅰ组、模型Ⅱ组。模型Ⅰ组为束缚结合直肠高敏刺激法,模型Ⅱ组为束缚结合冷水(冰水混合物,0℃)刺激法制作功能性肠病大鼠模型。并以血液指标、回肠和结肠的病理学变化及肠推动比来评定造模效果。结果1)血常规:模型Ⅰ、Ⅱ组白细胞数(WBC)、红细胞数(RBC)、淋巴细胞数(Lymph)、血小板数(PLT)与正常组比较无显著性差异(P>0.05);(2)血液生化:谷丙转氨酶(ALT)、谷草转氨酶(AST)、肌酐(CREA)、肌酸激酶(CK)、镁(Mg)、磷(P)、乳酸脱氢酶(LDH)与正常组相比无显著性差异(P>0.05)。(3)小肠推动比率:模型Ⅰ组和模型Ⅱ组小肠推动比率与正常组比较,显著降低(P<0.05)。(4)模型Ⅰ组与模型Ⅱ组大鼠回肠及结肠表现出基本一致的病理变化:回肠部分微绒毛顶部上皮细胞脱落、结构不完整,部分微绒毛固有层上皮细胞轻度水肿、核浓缩,固有层中毛细血管轻度扩张充血;结肠上皮细胞轻微肿胀、固有层毛细血管轻度扩张充血,偶见基层部分平滑肌细胞嗜酸性变,微绒毛固有层上皮细胞下有少量炎性细胞,偶见微绒毛上皮细胞脱落。结论两种造模方法均可复制出胃肠功能障碍的基本病理生理特征,即结肠、回肠均表现出一定的病理损伤,但未出现明显的炎性反应,小肠推动率有明显降低。两种大鼠模型均复制出胃肠功能障碍的基本病理特征,从操作方法上,当批量处理及特殊环境下造模时,推测模型Ⅱ方法操作性更高。

大鼠小肠移植模型的建立与改进

目的 为研究小肠移植排斥反应提供良好的动物模型。方法 选用SD大鼠进行一期同种异体异位节段性小肠移植。结果 模型稳定后 4 0次小肠移植的术后 5天存活率达 90 %。结论良好的血管吻合方法以及输血、补液、保温等围手术期处理是提高手术成功率的关键。

大鼠同种异体在体异位节段小肠移植模型的建立

目的:为研究抗小肠移植排斥治疗提供良好的动物实验模型。方法:选用大鼠进行同种异体异位节段性小肠移植。结果:共施行96只移植手术,模型稳定后的56只小肠移植5天成活率为85.71％。结论:本模型制作成功率较高,适合小肠移植排斥研究。

大鼠急性肠道感染后肠功能紊乱动物模型的建立

目的：模仿人类感染后肠易激综合征的自然发病过程，建立急性细菌感染后肠功能紊乱的大鼠模型。方法：将60只雌性Wistar大鼠分为正常对照组和实验组，实验组应用浓度为9×10^8CFU／ml的福氏志贺氏痢疾杆菌1ml灌胃造成急性肠道感染，正常对照组用等量生理盐水灌胃。于感染后观察大便性状，于1，4，7，10，13d行大便培养，远端结肠病理学检查，并于16，19，22，25d行直肠气囊扩张，测定肠道感觉阈值。结果：实验组大鼠于感染后第16～22天出现大便性状改变，肠道感觉阈值较正常对照组明显下降（P〈0．05），而大便福氏志贺氏痢疾杆菌培养（-），组织学恢复正常。结论：大鼠在急性肠道细菌感染后第16～22天，组织学炎症消失后，还存在着内脏高敏感，标志着大鼠急性肠道感染后肠功能紊乱模型建立成功。

大鼠原位肝移植动物模型制作要点

目的 建立稳定的大鼠原位肝移植模型。方法 参照 Kamada等法建立大鼠原位肝移植模型,经门静脉灌注肝脏,改进肝上下腔静脉吻合法为单线连续缝合法。结果 210只大鼠原位肝移植24 h存活率为91.0%(191/210),平均无肝期17 min,1周生存率为85.2%(179/210)。结论 改进大鼠原位肝移植肝上下腔静脉吻合法,可缩短受体无肝期,减少手术并发症发生率,并能提高原位肝移植大鼠的生存率。

大鼠原位肾移植模型的建立

目的为进行移植免疫研究的需要,建立一种大鼠肾移植模型。方法采用原位低温灌注、手术显微镜下原位端——端吻合肾动、静脉,将输尿管带膀胱瓣吻合于膀胱。结果建立了稳定可靠的大鼠肾移植模型,手术成功率为86%。结论此方法建立的模型稳定可靠,较为理想的满足了肾移植研究的需要。

力肽及精氨酸在大鼠移植肠缺血再灌注损伤治疗中的作用

目的 探讨 L -精氨酸 (L - Arginine,L - Arg)和力肽在大鼠小肠移植 (small bowel transplantation,SBT)缺血再灌注损伤中的治疗作用和协同效应 .方法 将 6 4只大鼠随机分为 4组 ,对照组 (n=16 )行虚拟手术 ,给予普通饲料喂养 ;s TPN组 (n=16 )行同系小肠移植 (syngeneic SBT) ,接受传统的肠外营养 ;d TPN组 (n=16 )行同系小肠移植 ,接受力肽强化的全胃肠外营养 (total parenteral nutrition,TPN) ;a TPN组 (n=16 )行小肠移植 ,给予加用 L - Arg和力肽的肠外营养 .各组于术后 2 0 m in和术后 8d(POD8)取材 .结果 小肠移植术后 2 0 min,移植肠中度缺血再灌注损伤表现 ,移植肠粘膜一氧化氮 (nitric oxid,NO)水平降低 ,丙二醛 (malondialde-hyde,MDA)含量升高 .术后 8d,a TPN组移植肠粘膜 NO水平高于对照组及 d TPN组 (P<0 .0 5 ,P<0 .0 1) ,d TPN组及 a TPN组移植肠粘膜谷氨酰胺 (glutamine,Gln)含量均高于 s TPN组 (P<0 .0 1,P<0 .0 1) ,a TPN组较显著 ;d TPN组及 a TPN组移植肠的绒毛高度、粘膜厚度均明显大于 s TPN组 .结论 大鼠在接受同系异体小肠移植术后 ,力肽强化的肠外营养液可促进移植小肠粘膜结构的修复 ,L- Arg可增强力肽对移植肠粘膜修复的作用 .