Xue Liang Jiang¹ and Hui Fei Cui^2
1Department of Gastroenterology, Chinese PLA General Hospital of Jinan Command, Jinan 250031, China
²Department of Biochemical Pharmaceutics, Shandong Medical University, Jinan 250012, Shandong Province, China
Dr. Xue Liang Jiang, graduated from Shandong Medical University as a postgraduate in 1993, associate professor of gastroenterology, major in immunology of digestive diseases, having 40 papers published.
Supported by Key Research Fund of Jinan Command, No.9801
Correspondence to: Dr. Xue Liang Jiang, Department of Gastroente rology, Chinese PLA General Hospital of Jinan Command, 25 Shifanlu, Jinan 250031, Shandong Province, China
Telephone: 0086-531-2600132, Fax. 0086-531-2029999 Ext.01166
Email. chfjxl@jn-public.sd.cninfo.net
Received: 2000-05-18 Accepted: 2000-06-23

Subject headings: colitis, ulcerative; animal model; 2,4-dinitrochlorobenzene; acetic acids; apoptosis; flow cytometry; intestinal mucosa/pathology

Jiang XL, Cui HF. A new chronic ulcerative colitis model produced by combined methods in rats. World J Gastroentero, 2000;6(5):742-746

INTRODUCTION
The etiopathogenesis of ulcerative colitis (UC) remains obscure, due to lack of an ideal animal model^[1-8]. With the improvement of theory and methodology in the last 30 years, people used to adopt chemicals (acetic aci d, ethanol, carrageen, etc.), immunotechniques (humoral or cellular immunity, immune complex) and substance derived from UC patients to set up various kind s of UC animal model, which mimic the pathologic changes of human UC, so far th ese remain far from reality^[6-10]. A possible exception is the spontaneo us colitis developed in the cotton-top tamarin when captured, but this animal is rarely available and expensive preventing its usage^[11]. Therefore, establishing an ideal animal model becomes the focus and key of the research study of UC. Nowadays, the models produced by 2,4-dinitrochlorobenzene (DNCB) and acetic acid (AA) came into use because of their simplicity and patho logic changes simulating those of human UC^[12-21], however, the characteristics of short course of DNCB method and absence of immunoreactivity in AA method, these two models are not ideal either. In the present study, we established a new rat UC model produced by combination of DNCB and AA, and observed the changes of general condition, the disease course, the pathology, ultrastructure, apoptosis, immunoreaction and intracolonic pressure, in order to develop a more ideal UC animal model.

MATERIALS AND METHODS
Materials
Eighty healthy male and female adult Wistar rats weighing 250g-350g were used in this study. They were provided by the Department of Experimental Animal of our hospital, and were raised in the SPF environment (constant tempera ture, humidity and sterilized water, food and padding) and acclimatized to the surrounding for 7 days prior to the experiments.
      DNCB (First Reagent Factory of Shanghai), AA (Dongtai Reagent Factory), CD₄, CD₂₉ and FITC or PE conjugated monoclonal antibodies (Immunotech, Marseilles, France), PC polygraf HR multichannel recording system (CTD-SYNECTICS Ltd), scanning electron microscope (EX1200, Japan), flow cytometry FACScan (Becton Dickenson Immunocytometry System).

Methods
Animal models Eighty Wistar rats were divided randomly into 4 g roups, 20 each. Group A (DNCB+AA): after the nape hair was depleted by 10% Na₂S, DNCB acetone solution (20g/L) was dropped to the nape of the rats (0.3mL for each) once daily for 14 days, on the 15th day, nylon catheter (3mm in diameter) was inserted into the colon at the site of 8cm from the anus, and 0.25mL 0.1% DNCB, 50mL/L 0.04mol/L solution alcoho l were infused, on the 16th day, 2mL AA solution (80mL/L) were infused into the same site for 15s, then 5mL normal saline (0.9%) was used to washout AA. Group B (DNCB only): from the 1st day to the 14th day, the method was similar to that for Group A, from the 15th day to the 18th day, 0.25mL 0.1% DNCB (50mL/L) alcohol solution (0.04mol/L) were infused into the colon at 8cm depth by the same nylon catheter once a day for each. Group C (AA only): 2mL AA (80mL/L) solution were infused into the colon at 8 cm depth by intracolonic administration with nylon catheter (3mm in diameter) for 15s, then 5mL saline for washing the AA. Group D (saline control): equivalent volume of normal saline was given in the method similar to that for Group A.

Pathological observation After the model had been established, the rats were killed at wk1, 2, 4, 8 and 16, and the distal colon (7cm-9cm) were removed longitudinally and washed to remove the luminal contents, tissues were fixed in 10% neutral-buffe red formalin, dehydrated according to the routine, embedded in paraffin wax and sectioned. Finally, the sections were stained with HE and observed microscopical ly. Apoptotic cells were identified morphologically^[22], for cell shrink age, chromatin condensation, formation of apoptotic bodies. Apoptosis was calculated randomly by counting the apoptotic bodies in the lamina propria for at least 200 cells^[22].

Electron microscopy The tissues were cut into small pieces (0.5mm in diameter) and fixed first in 2.5% glutaraldehyde buffered in 0.1M PBS (pH 7.2) at 4℃ for at least 2h. The tissues were washed with the same buffer and then fixed in 1% osmium tetroxide in phosphate buffer at 4℃ for 2h, dehydrated in graded series of acetone and embedded in epoxy resin 812. The ultrathin sections were observed under EX1200 electron microscope.

Measurement of CD₄⁺CD₂₉⁺ Blood CD₄⁺CD₂₉⁺ were measured using flow cytometry according to our previous article^{[15 ,23]}.

Colonic pressure and motility Intracolonic pressure and motility were measured according to our previous report through pressure tranducer and recorded by PC Polygraf HR multichannel recording system^[24](Figure 1). During manometry, the catheter lumen was infused with 0.9% saline at 0.2mL/min using a miniature hydraulic infusion pump. The baseline resistance of intra colonic pressure was set at zero. The catheter (outer diameter 3mm with 4 side holes for 4 channels) was inserted into the colon at 9cm depth from the anus without laparotomy, and was withdrawn at 1mm-2mm increment, and measurement was not started until 5min after the tip of the catheter dropped out into the rectum.

Statistical analysis The data were expressed as x-±s , and analyzed, using the Student＇s t test P＜0.05 was consid ered significant.

RESULTS
General condition and disease course Anorexia, bloody diarrhea, mucus in stools were seen in all A, B and C groups after 1 to 2 weeks, which lasted for 16 weeks in group A with weight loss and 8 weeks in group C, while in group B, the bloody diarrhea and mucus in stools decreased gradually and recovered 2 weeks later. No symptoms were observed in group D.

Pathological findings Diffuse hemorrhage, edema, congestion, superficial ulceration in the mucosa with infiltration of lymphocytes, plasma cells and polymorphonuclear cells, cryptitis, crypt abscess could be observed in all A, B and C groups (Figure 2), and these characteristics lasted for 16 weeks in group A and 8 weeks in group C while only 2 weeks in group B. In group D, the bowel wall was normal by gross and microscopic examinations.

Ultrastructural changes There were decreased number of cells, shortened microvilli, swollen mitochondria with depleted ridge, maldevelopmen t of goblet cell and increased number of lysosomes during the acute phase (Figure 3), which recovered to normal gradually (Figure 4).

Apoptosis The apoptosis indexes, 9.9±3.8 in group A, 8.6±3.5 in group B, 8.1±2.9 in group C, were significantly higher than those in group D (4.0±2.1, P＜0.05). Under scanning electronmicroscope, shrinkage of cells, condensation and margination of chromatin could be seen (Figure 5).

Immunoreactivity The changes of CD₄⁺CD₂₉⁺ in ulcerative colitis models were shown in Table 1. CD₄⁺CD₂₉⁺ increased significantly (P＜0.01) in group A and B but not in group C and D 1 week after set up of model (P＞0.05).

Table 1 Changes of CD₄⁺CD₂₉⁺ in ulcerative colitis models (%, x-±s)

^bP＜0.01 vs prior to set up of model.

Colonic pressure and motility
One week after set up of the model in group A, the basal intracolonic pressure was apparently lower than that of the pre-model (proximal pressure: 0.78kPa±0.13kPa vs 0.88kPa ±0.14kPa, distal pressure 0.76kPa±0.11kP a vs 0.89kPa±0.15kPa, P＜0.05). The frequency of migrating motor complex waves in vivo were significantly faster 1 week after set up of the model as compared with that prior to (1.59/min±0.27/min vs 0.60/min±0.12/min,P＜0.05) in 7 rats of group A, this belonged to the pathologic colon of high dysrhythmia. The amplitude of migrating motor complex waves decreased markedly in 10 rats of group A after 1 week of post-model than that of pre-model (proximal pressure: 0.64kPa±0.24kPa vs 1.98kPa±0.38kPa, distal pressure: 0.92kPa±0.37kPa vs 2.45kPa±0.63kPa, P＜0.01), which belonged to asthenia colon. In the other 3 rats, while the proximal amplitude of migrating motor complex waves were lowered significantly (0.96kPa±0.31kPa), the distal amplitude of migrating motor complex waves remained still higher (2.35kPa±0.50kPa).

Success rate The ulceration pattern was present in all 20 rats of group A, the success rate therefore, could be considered 100%.

Figure 1 Measurement of intracolonic pressure and motility in UC rats without laparotomy.
Figure 2 Pathological features of ulcers and crypt abscess. HE×25
Figure 3 Swelling of mitochondria with ridge depletion in goblet cell. ×4000
Figure 4 In healing phase, the decreased number of the cell count and swelling of mitochondria recovered to normal gradually. ×10K
Figure 5 Apoptosis of epithelia cell with condensa tion and margination of chromatin. ×12K

DISCUSSION
So far, the precise etiopathogenesis of UC remained unelucidated^[1,25-40] , though experimental colitis had been produced by various methods mimiking human UC somehow, up to the present there is not one ideal animal model which conforms with human UC in pathogenesis, pathology and biologic behavior^[6-21,41,42]. An ideal animal model should fullfil the following requirements^[15,24]: ① it should reflect the histological characteristics of the diseases; ② it should be autoimmune in nature; ③ it should have the similar clinical manifestations as in human UC; ④ it should be simple and reproducible. In this study, the UC model produced by AA method was related to its chemical stimulation to the colonic mucosa^[12-14], which led to increment of vascular permeability and activate inflammation mediators, resulting in bloody diarrhea, mucus in stools and histological features as diffuse edema, congestion and ulceration, crypt abscess and mucosal  infiltration of inflammation cells. It can be used to study the inflammatory mechanism and anti-inflammatory drugs^[43-45], but it lacked the immun e response which is a dsawback.
      DNCB is a hapten, when bound with tissue proteins will be able to elicit immunologic response and induce colitis^[18-21]. The clinical symptoms and histological features, in particular CD₄⁺CD₂₉⁺ cells are similar to those of human UC, but the self-limited course of 2 weeks, is too short to be utilized as an ideal model.
      In order to overcome these shortcomings we establish a new chronic UC model by using DNCB and AA in combination which has the following advantages^[15-17]. ① Clinically it manifests mucus in stools, bloody diarrhea and weight loss, just like those occur in human UC. ② It can reflect the pathologic characteristics of UC, such as continuous superficial coloni c inflammation. Microscopically there exist mucosal edema and congestion, infiltration of lymphocytes, plasma cells and polymorphonuclear cells, crypt abscresses and ulceration. ③ It is an immune response model, immunology is well studied in UC^[1,46-49]. One of the important immunoregulatory abnormality in UC is related to the T cell response^[23,50]. CD₄ interacts with HLA class Ⅱ molecules, CD₄ positive T cells can be divided into Th1 and Th2 cells whreas CD₂₉ reacts with 130 KD integrin β₁ subunit which is expressed as a heterodimeric complex with one of six α subunits, forming the very late activation antigen (VLA) subfamily of adhesion receptors. The β₁ subunit has a broad distribution, and is expressed on lymphocytes, monocytes but weakly on granulocytes. These receptors are involved in a variety of cell-cell and cell- matrix interactions. Co-expression of CD₄⁺ and CD₂₉⁺ can be used as a marker to identify the Th1 cells subgroup, whose main function is to help B lymphocyte to induce antibody production and cell-mediated dissolution^[15,23]. The increase of CD₄⁺CD₂₉⁺ can lead to highly activated B lymphocyte and immunoregulatory abnormality. In this test, CD₄⁺CD₂₉⁺ cells are significantly higher after the set up of models by combination of DNCB and AA, Which is in accord with the requirement of immune response similar to that in human UC. ④ It has a long disease course, if can last at least for 16 weeks with chronic damage of the bowel hence, eligible for the assessment of the drug effects. ⑤ The ultrastructural features are similar to those of human UC. The decreased number of epithelial cells and shortened microvilli, swelling of mitochondria with depletion of ridges can lead to impairment of water absorption of colon resulting in diarrhea.The maldevelopment of goblet cell, may lead to mucus in stools. ⑥ The above findings are not only consistent with the changes in human UC^[51-59], but also concordant with other reports^[60,61]. The model produced by combination of DNCB and AA is a more ideal animal model of UC. Apoptosis was first described by Kerr^[62] and is referred to as programmed cell death, which is genetically controlled. In active UC, injury is common. Did apoptotic cells increase in colonic epithelia which led to ulcera tion? This hypothesis had been studied since 1996^[63-67]. Apoptosis of the normal colon was localized in the superficial epithelium, far less than one apoptotic body per crypt. In active UC, the loss of epithelial cells occurred mainly by apoptosis in crypts of involved and uninvolved adjacent areas, resulting in impairment of protective mucosal barrier. The mediators of apoptosis are partly related to the Fas/Fas-L interaction and/or changes in Bcl-2 expression. Our previous study demonstrated the number of apoptotic cells of colonic mucosal epithelial cells in human UC increased as shown by flow cytometry^[68], This led to the damage of the barrier resulting in ulceration. Under scanning electron microscope, shrinkage of cells, condensation and margination of chromatin could all be seen.
      The symptoms of diarrhea and abdominal pain are partly related with colonic motility disturbance^[69-75]. In this study, we first used PC Polygraf HR multichannel recording system to measure the intracolonic pressure and motility in physiological and pathological conditions from multiple sites over prolonged periods. The resultant signals were digitized, analyzed and displayed in a readily interpretable manner, and could be easily subjected to a variety of statistical manipulations, as the colon was situated within the abdominal cavity, the temperature, humidity and pH were maintained by the rats themselve s, and not interfered by operative maneuver. In this study, UC rats are characterized by decreased intracolonic basal pressure and disturbance of frequency and amplitude of migrating motor complex which may lead to the symptoms of urgency, diarrhea and abdominal pain. In conclusion, the new chronic UC rat model produced by combination of DNCB and AA is similar to human UC in clinical manifestations, histology, ultrastructural changes, immune response, apoptosis and colonic motility, and it is simple, inexpensive and reproducible with high successful rate.

REFERENCES
1    Jiang XL,Quan QZ,Liu T,Dong XC.Recent advances in research of ulcerative colitis.Shijie Huaren Xiaohua 
      Zazhi,2000;8:216-218
2    Jiang XL, Wang ZK, Qin CY. Current research and strategy on ulcerative colitis in China.
      Shijie Huaren Xiaohua Zazhi,2000;8:610-613
3    Yi JY, Xia B, Huang MF, Fu N, Deng CS. Observation of experimental model of ulcerative colitis in rats.
      Xin Xiaohuabingxue Zazhi,1997;5:721-722
4    He QX, Chen YB, Jia YL, Li XY, Jiang HY. The effects of immune complex on ulcerative colitis.Huaren Xiaohua 
      Zazhi,1998;6:87
5    Zou YH, Zhang YB, Chen WQ, Zhong TJ, Liu XQ, Zhao H, Lian ZC, Su Q, Su XR, Huang HD. Effects of Chinese medicine
      compound Weichangkang on rat ulcerative colitis and its NO abnormality.Huaren Xiaohua Zazhi,1998;6:288-290
6    Gryglewski A, Szczepanik M, Szczepanik R. Colitis in laboratory experimentation. Przegl Lek,1997;54:558-560
7    Dieleman LA, Pena AS, Meuwissen SG, van Rees EP. Role of animal models for the pathogenesis and treatment of
      inflammatory bowel disease.Scand J Gast roenterol,1997;223(Suppl):99-104
8    Kim HS, Berstad A. Experimental colitis in animal models.Scand J Gastroe nterol,1992;27:529-537
9    Strobe W. Animal models of inflammatory bowel disease—an overview.Dig Dis Sci,1985;30:3s-10s
10  Cominelli F, Dinarello CA. Interleukin 1 in the pathogenesis of and protection from inflammatory bowel disease.
      Biotherapy,1989;1:369-375
11  Warren BF. Cytokines in the cotton top tamarin model of huaman ulcera tive colitis.
      Aliment Pharmacol Ther,1996;10(Suppl):45-47
12  Nosal＇ova V, Bauer V. Protective effect of stobadine in experimental colitis.Life Sci, 1999;65:1919-1921
13  Biondo Simoes M, De L, Sech M, Corbellini M, Schimarelli G, Veronese C, Ramos L,Collaco LM. Comparative study of
      the evolution of inflammatory colitis treated with an elemental diet, glutamine and 5 ASA. An experimental study in 
      rats. Arq Gastroeterol,1998;35:116-125
14  Higa A, Eto T, Nawa Y. Evaluation of the role of neutrophils in the pathogenesis of acetic acid induced colitis in mice.
      Scand J Gastroenterol,1997;32:564-568
15  Jiang XL, Quan QZ, Wang D, Sun ZQ, Wang YJ.The changes of immune re sponse and ultrastructure in experimental
      colitis produced by combined methods in rats.Shijie Huaren Xiaohua Zazhi,1999;7:381
16  Jiang XL, Quan QZ, Wang D, Sun ZQ, Wang YJ, Qi F. Experimental study of ulcerative colitis treated with Herba
      Houttuyniae.Shijie Huaren Xiaohua Zazhi,1999;7:786
17  Jiang XL, Quan QZ, Wang D, Sun ZQ, Wang YJ, Qi F. Experimental ulcerative colitis produced by combined methods in
      rats.QinghaiYixueyuan Xuebao,1999;20:1-3
18  Mack DR, Lau AS, Sherman PM. Systemic tumor necrosis factor—alpha production in experimental colitis.
      Dig Dis Sci,1992;37:1738-1745
19  Rozga J. Ulcerative colitis in the experimental animal. Acta Physiol Pol,1990;45:105-113
20  Onderdonk AB. Experimental models for ulcerative colitis. Dig Dis Sci,1985;30:40s-44s
21  Meyers S, Sachar DB, Taub RN, Janowitz HD. Significance of anergy to dinitrochlorobenzene (DNCB) in inflammatory 
      bowel disease: family and postoperative studies.Gut,1978;19:249-252
22  Chen XQ, Zhang WD, Song YG, Zhou DY. Induction of apoptosis of lymphocytes in rat mucosal immune system.
      World J Gastroentero,1998;4:1 9-23
23  Jiang XL, Quan QZ, Wang D, Sun ZQ, Wang YJ, Qi F. Effect of glucocorticoid on lymphocyte adhesion molecule 
      phenotype expression in patients with ulcerative colitis.Zhongguo Weizhongbing Jijiu Yixue,1998;10:366-368
24  Jiang XL, Quan QZ, Wang D, Sun ZQ, Wang YJ, Qi F. Effects of Herba Hou ttuyniae of colonic pressuer.
      Shijie Huaren Xiaohua Zazhi,1999;7:639
25  Wu XN. Recent advances in mechanic study of ulcerative colitis.Xin Xiaohuabingxue Zazhi,1995;3:129-131
26  Xia B, Crusius JBA, Meuwissen SGM, Pea AS. Inflammatory bowel disease: definition,epidemiology, etiologic aspects, 
      and immunogenetic studies.World J Gastroentero,1998;4:446-458
27  Cui HF, Jiang XL. Treatment of corticosteroid resistant ulcerative colitis with oral low molecular weight heparin.
      World J Gastroentero,1999;5:448-450
28  Xu CT, Wang RL, Ma LS. Alterations of serum motilin, peptide YY, IgG and ferritin in patients with ulcerative colitis.
      Xin Xiaohuabingxue Zazhi, 1997;5:247-248
29  Zhang L, Wang AM, Guo RF, Zhang WN. Serum soluble interleukin 2 recep tor level in patients with ulcerative colitis.
      Xin Xiaohuabingxue Zazhi,1997;5(4):251-252
30  Chen X, Zhang ZY, Xu ED, Na JH, Yang NH. Bone mineral density and serum Ca, P and Mg in ulcerative colitis patients.
      Xin Xiaohuabingxue Zazhi, 1997;5:385-386
31  Li HM. The mechanic study and characteristics of treatment in patient s with ulcerative colitis.
      Huaren Xiaohua Zazhi,1998;6:726-728
32  Jiang XL, Quan QZ, Sun ZQ, Wang YJ, Qi F, Wang D, Zhang XL. Expression of apoptosis on lymphocyte in patients with
      ulcerative colitis. Shijie Huaren Xiaohua Zazhi,1999;7:903-904
33  Tai WP, Luo HS. Short chain fatty acids in pathogenesis and treatment of ulcerative colitis.
      Shijie Huaren Xiaohua Zazhi,2000;8:96-97
34  Wen B, Ma GF. Determination of plasma nitric oxide, molitin and their significances in ulcerative colitis.
      World J Gastroentero,1998;4(Suppl 2): 69
35  Wang JN, Li ZF, Fu Y, Ke Y, Xu YC, Lin GB. Changes of serum TNFα and IL-6 in patients with ulcerative colitis.
      Shijie Huaren Xiaohua Zazhi,1999;7:727-728
36  Wu HG, Zhou LB, Pan YY, Huang C, Chen HP, Shi Z, Hua XG. Study of the mechanisms of acupuncture and moxibustion
      treatment for ulcerative colitis rats in view of the gene expression of cytokines.World J Gastroentero,1999;5:515-517
37  Xia B, Shivananda S, Zhang GS, Yi JY, Crusius JBA, Pea AS. Inflammat ory bowel disease in Hubei Province of China.
      China Natl J New Gastroenterol,1997;3:119-120
38  Shivananda S. Epidemiology and disease outcome in inflammatory bowel disease: observations from the European
      Collaborative Study.World J Gastroentero,1998;4(Suppl 2):25-26
39  Hu QY, Hu XY, Jiang Y. Clinical investigation of ulcerative colitis patients treated by integrated traditional Chinese and
      Western medicine.World J Gastroentero,1998;4(Suppl 2):93-94
40  Wu HG, Zhou LB, Huang C, Pan YY, Chen HP, Shi Z, Hua XG.Gene expression of cytokines in acupuncture and 
      moxibustion treatment for ulcerative colitis in rats.Huaren Xiaohua Zazhi,1998;6:853-855
41  Zheng L, Gao ZQ, Wang SX. A chronic ulcerative colitis model in rats.World J Gastroentero,2000;6:150-152
42  He QW, Chen YM, Jia YL, Li XY, Qian HY. Pathogenic effects of immune complexes.Huaren Xiaohua Zazhi,1998;6:87
43  Cui SY, Zhang HB, Wu CZ, Sun GC, Zhao WP, Xu T, Li M. The clinical and experimental treatment of ulcerative colitis 
      using Bupisan.Xin Xiaohuabingxue Zazhi,1997;5:219-220
44  Zhu BX, Lu YM. Effect of sulfphasalazine on the colonic mucosal malondialdehyde in patients with ulcerative colitis.
      Xin Xiaohuabingxue Zazhi,1997;5:619-620
45  Zhu BX, Lu YM, Ye SM. Effects of sulfphasalazine on oxygen free radicals in experimental colitis.
      Xin Xiaohuabingxue Zazhi,1997;5:769-770
46  Jiang XL, Quan QZ, Liu TT, Wang YJ, Sun ZQ, Qi F, Ren HB, Zhang WL, Zhang L. Measurement of platelet activation in
      patients with ulcerative colitis.Xin Xiaohuabingxue Zazhi,1997;5:736
47  Jiang XL, Quan QZ, Sun ZQ, Wang YJ, Qi F. Expression of adhesion molecules in tissues and peripheral lymphocyte of
      patients with ulcerative colitis.Huaren Xiaohua Zazhi,1998;6:54-55
48  Jiang XL, Quan QZ, Sun ZQ, Wang YJ, Qi F, Wang D, Zhang XL. Detection of soluble CD44v6 in patients with 
      inflammatory bowel disease.Shijie Huaren Xiaohua Zazhi,1999;7:1028
49  Xia B, Guo HJ, Crusius JBA, Deng CS, Meuwissen SGM, Pe a AS.In vitro production of TNFα, IL 6 and sIL 2R in Chinese
      patients with ulcerative colitis.World J Gastroentero,1998;4:252-255
50  Jin W, Wu SH, Zhang ZJ, Lin PG, Ren ZQ, Sui WL. Effects of Changyanning on T lymphocyte subsets in patients with
      ulcerative colitis.Shijie Huaren Xiaohua Zazhi,1999;7:616-617
51  Mughal S, Filipe MI. Ultrastructural study of inflammatory bowel disease.Histol Histopathol,1992;7:599-605
52  Shields HM, Bates ML, Goldman H, Zuckerman GR, Mills BA, Best CJ,Bair FA, Goran DA, DeSchryver Kecskemeti K. 
      Scanning electron microscopic appearance of chronic ulcerative colitis with and without 
      dysplasia.Gastroenterology,1985;89:62-72
53  Laschi R, Pasquinelli G, Versura P. Scanning electron microscopy application in clinical research.
      Scanning Microsc,1987;1:1771-1795
54  Specian RD, Oliver MG. Fuctional biology of intestinal goblet cells.Am J Physiol,1991;260:c183-193
55  O＇Morain C, Smethurst P, Levi J, Peters TJ. Subcellular frctionation of rectal biopsy homogenates from patients with
      inflammatory bowel disease.Scand J Gastroenterol,1985;20:209-214
56  Balazs M, Kovacs A. Ulcerative colitis: electron microscopic studies with special reference to development of crypt 
      abscesses. Dis Colon Rectum,1989;32:327-334
57  Mack DR, Lau AS, Sherman PM. Systemic tumor necrosis factor alpha production in experimental colitis.
      Dig Dis Sic,1992;37:1738-1745
58  Kao HW, Zipser RD. Exaggerated prostaglandin production by colonic smooth muscle in rabbit colitis.
      Dig Dis Sci,1988;33:697-704
59  Delpre G, Avidor I, Steinherz R, Kadish U, Ben Bassat M. Ultrastructural abnormalities in endoscopically and histologically
      normal and involved colon in ulcerative colitis.Am J Gastroenterol,1989;84:1038-1046
60  Rumessen JJ. Ultrastructure of interstitial cells of Cajal at the colonic submuscularis border in patients with ulcerative 
      colitis. Gastroenterology,1996;111:1447-1455
61  Kaftan SM, Wright NA. Studies on the mechanisms of mucous cell depleti on in experimental colitis.J 
      Pathol,1989;159:75-85
62  Kerr JF, Wyllie AH, Currie AR. Apoptosis: a basic biological phenomen on with wild ranging implications in tissue 
      kinetics. Br J Cancer,1972;26:239-245
63  Ueyama H, Kiyohara T, Sawada N, Isozaki K, Kitamura S, Kondo S, Miyagawa J, Kanayama S, Shicnomura Y, Ishikawa H,
      Ohtani T, Nezu R, Nagata S,Matsuzawa Y. High fas ligand expression on lymphocytes in lesions of ulcerative colitis.
      Gut,1998;43:48-55
64  Strater J, Wellisch I, Riedl S, Walczak H, Koretz K, Tandara A, Kramme r PH, Moller P. CD95(APO 1/.Fas) mediated 
      apoptosis in colon epithelial cell s: a possible role in ulcerative colitis.Gastroeterology,1997;113:160-167
65  Iwamoto M, Koji T, Makiyama K, Kobayashi N, Nakane PK. Apoptosis of crypt epithelial cells in ulcerative colitis.
      J Pathol,1996;180:152-159
66  Kraus MD, Shahsafaei A, Antin J, Odze RD. Relationship of Bcl-2 expression with apoptosis and proliferation in colonic 
      graft versus host disease .Hum Pathol,1998;29:869-875
67  Sakai T, Kimura Y, Ohara KI, Kusugmi K, Lynch DH, Yoshikai Y. Fas mediated cytotoxity by intestinal intraepithelilal 
      lymphocyte during acute graft versus host disease in mice. Gastroenterology,1997;113:167-174
68  Jiang XL, Quan QZ, Chen GR, Sun ZQ, Wang YJ, Wang YP. Expression of apoptosis in tissues of ulcerative colitis.
      Shijie Huaren Xiaohua Zazhi,2000;8:107-10
69  Reddy SN, Bazzocchi G, Chan S, Akashi K, Villanueva Meyer J, Yanni G, Mena I, Snape WJ. Colonic motility and transit in 
      health and ulcerative colits.Gastroenterology,1991;101:1289-1297
70  Muraoka M, Kimura G, Zhaopeng H, Takada K. Ulcerative colitis—colon delivery of 5 aminoslicylic acid.
      Nippon Rinsho,1998;56:789-794
71  Rao SS, Read NW. Gastrointestinal motility in patients with ulcerative colitis.Scand J Gastroenterol,
      1990;172(Suppl):22-28
72  Snape WJ,Kao HW.Role of inflammatory mediators in colonic smooth muscle in ulcerative colitis.Dig Dis 
      Sci,1988;33:65s-70s
73  Sethi AK, Sarna SK. Colonic motor response to a meal in acute colitis.Gastroenterology,1991;101:1537-1546
74  Aube AC, Cherbut C, Barbier M, Xing JH, Roze C, Galmiche JP. Altered myoelectrical activity in noninlamed ileum of rat 
      colitis induced by trinitrobenzene sulphonic acid.Neuogastroentero Motil,1999;11:55-62
75  Collins SM, Barbara G, Vallance B. Stress, inflammation and the irrita ble bowel syndrome.   Canad J 
      Gastroentero,1999;13:47a-49a

Reviews	Add
more>>