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Brief Report  |   May 2020
Effect of Abdominal Lymphatic Pump Treatment on Disease Activity in a Rat Model of Inflammatory Bowel Disease
Author Notes
  • From the Ohio Valley Medical Center in Wheeling, West Virginia (Dr Schander); the Department of Physiology and Anatomy (Drs Castillo and Hodge); the Department of Family Medicine (Dr Paredes); and the Osteopathic Research Center (Dr Hodge) at the University of North Texas Health Science Center in Fort Worth. 
  • Financial Disclosures: None reported. 
  • Support: This research was supported by the American Osteopathic Association (grant No. AOA F12-02) and the American Academy of Osteopathy. 
  •  *Address correspondence to Lisa M. Hodge, PhD, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107-2644. Email: lisa.hodge@unthsc.edu
     
Article Information
Gastroenterology / Osteopathic Manipulative Treatment
Brief Report   |   May 2020
Effect of Abdominal Lymphatic Pump Treatment on Disease Activity in a Rat Model of Inflammatory Bowel Disease
The Journal of the American Osteopathic Association, May 2020, Vol. 120, 337-344. doi:https://doi.org/10.7556/jaoa.2020.052
The Journal of the American Osteopathic Association, May 2020, Vol. 120, 337-344. doi:https://doi.org/10.7556/jaoa.2020.052
Abstract

Context: Inflammatory bowel disease (IBD), such as ulcerative colitis and Crohn disease, are chronic relapsing inflammatory diseases that affect 1.5 million people in the United States. Lymphatic pump treatment (LPT) techniques were designed to enhance the movement of lymph and can be used to relieve symptoms in patients with IBD and other gastrointestinal disorders.

Objective: To determine whether LPT would decrease gastrointestinal inflammation and reduce disease severity in rats with acute IBD.

Methods: On day 0, rats were randomized into control or experimental groups. Control rats received normal drinking water for days 0 to 9. On days 0 to 9, rats in the experimental groups received drinking water containing 3.5% dextran sodium sulfate (DSS). On day 3, experimental rats were randomized into 3 groups. On days 3 to 8, experimental rats received either (1) no treatment or anesthesia (DSS alone); (2) 4 minutes of LPT with anesthesia administration (DSS+LPT); or (3) 4 minutes of sham treatment (ie, light touch) and anesthesia (DSS+sham). On day 9, colons and gastrointestinal lymphoid tissue were collected. Colon weight, histologic changes, disease activity index (DAI) score, and the concentration of leukocytes were measured.

Results: At day 9, the mean (SD) DAI score in the DSS+LPT group (1.0 [0.1]) was significantly decreased (P<.01) compared with the DAI score of DSS-alone rats (1.5 [0.1]). While the DAI in DSS+LPT rats was reduced on days 8 to 9, this difference was not statistically different (P>.05) compared with DSS+sham (1.3 [0.1]). No significant differences were found in colon weight, histopathologic findings, or the concentration of gastrointestinal leukocytes between DSS alone, DSS+sham, or DSS+LPT (P>.05).

Conclusion: While DSS+LPT reduced IBD compared with DSS+sham, the decrease was not statistically significant. Considering the growing use of adjunctive treatment for the management of IBD, it is important to identify the effect of osteopathic manipulative medicine on IBD progression.

Inflammatory bowel disease (IBD) is a chronic, relapsing, idiopathic inflammation of the gastrointestinal tract. The disease process has 2 predominant presentations: Crohn disease and ulcerative colitis. In patients with IBD, the chronic inflammation of the gastrointestinal tract causes a progressive loss of the ability to adequately perform digestion and absorption. Thus, regardless of subtype, IBD may lead to malnutrition, gastrointestinal dysfunction and deterioration, and systemic inflammation, such as fever and musculoskeletal and dermatologic diseases.1-3 
Research into IBD has been focused on the genetic, microbial, and immunologic aspects of the disease process. Historically, IBD was commonly understood as a derangement of the gastrointestinal lymphatic anatomy. Specifically, the accumulation of inflammatory mediators in the gastrointestinal lymphatics leads to a decrease in lymphatic vessel contractility, edema, and impaired immune cell trafficking.4,5 Therefore, treatments that improve mesenteric lymph flow may minimize colonic inflammation and restore lymphatic function in the bowel. 
Select osteopathic manipulative treatment (OMT) techniques are dedicated to the movement of lymphatic fluid.6-8 For the appendicular and axial fascia, there are various means of effleurage and petrissage. For the visceral fascia, lymphatic pump treatment (LPT) may be used. These techniques involve the application of rhythmic oscillatory compressions into the abdomen and rib cage.6-8 Patients with irritable bowel syndrome (IBS) who received visceral OMT techniques had decreased disease severity scores and improved quality of life.9-11 Therefore, OMT may be likely to have a therapeutic effect on patients with IBD. 
Unlike IBS, IBD is a chronic inflammatory process that results in inflammation and lymphatic dysfunction in the intestine.3 In 2018, a single-blind, randomized controlled trial12 measured the effects of soft tissue techniques on the quality of life of patients with Crohn disease. Thirty patients with Crohn disease were randomized into an experimental or control group. The experimental group received treatment sessions comprising the cranial temporal rotation technique, neurolymphatic reflexes technique, viscerosomatic reflexes technique, myofascial induction technique, and the visceral technique. The intervention period lasted 30 days with 1 treatment session occurring every 10 days. The authors12 reported that these soft tissue techniques improved functional and overall quality of life for patients with Crohn disease when compared with controls. In a 2006 case report,13 OMT was used in a patient with Crohn disease and was able to reduce disease symptoms. Collectively, these reports12,13 support the use of OMT as an adjunctive treatment for IBD; however, the mechanism of protection offered by OMT remains unknown. 
It is plausible that OMT mobilizes stagnant lymph pools in the mesentery, which may reduce inflammation in patients with IBD. In support of this theory, abdominal LPT significantly enhanced lymph flow, leukocyte concentration, and the flux of inflammatory mediators in the mesenteric lymph of canines.14-16 Furthermore, the lymph mobilized during abdominal LPT suppressed the inflammatory activity of endotoxin-activated macrophages in vitro.17 This discovery suggests that the lymph mobilized during LPT may protect against inflammation. 
In 2010, a rat model was developed to study the effect of abdominal LPT on the lymphatic and immune systems.18 In this model, abdominal LPT significantly increased lymph and leukocyte flow in the cisterna chyli, and a significant portion of the lymphocytes mobilized during abdominal LPT were from the gastrointestinal lymphoid tissue. The development of this rat model allowed researchers to study the effectiveness of abdominal LPT at protecting against disease.19 
The purpose of the present study was to determine whether abdominal LPT would reduce disease severity in rats with colitis. The dextran sodium sulfate (DSS) murine colitis model was chosen for this study because it has been documented to produce biochemical, clinical, and histopathologic changes in mice, rats, and hamsters that are similar to human disease.20-25 Specifically, we hypothesized that the application of abdominal LPT once daily would decrease gastrointestinal inflammation and reduce disease severity in rats with acute DSS-induced colitis. 
Methods
Animals
This study was approved by the University of North Texas Health Science Center's Institutional Animal Care and Use Committee (protocol #2016-0032) and was conducted per the Guide for the Care and Use of Laboratory Animals.26 Seventy male Wistar rats, weighing between 275 and 300 g (approximately 6 weeks of age) and free of clinically evident signs of disease were used for this study). The weight, age, strain, and sex of the rats were chosen based on previous studies using the DSS model.20-25 
The rats were housed alone to record individual water consumption and stool consistency during this study. They exhibited mild signs of disease; therefore, no rats were euthanized early to prevent undue suffering. After the study, the rats were euthanized per the American Veterinary Medical Association guidelines.27 The experimental design for this study is summarized in Figure 1. 
Figure 1.
Study design. On days 0 to 8, normal drinking water was replaced with water containing a 3.5% dextran sodium sulfate solution (DSS) for the experimental rats. Healthy rats (negative controls) received normal drinking water or no treatment or anesthesia. On day 3 after induction, experimental rats were randomized into 3 treatment groups, and on days 3-8, they received (1) no treatment or anesthesia; n=17; (2) 4 minutes of sham treatment with anesthesia (n=18); or (3) 4 minutes of lymphatic pump treatment (LPT) with anesthesia (n=18). Nine days after the induction of inflammatory bowel disease, rats were euthanized, and their colons and gastrointestinal lymphoid tissue were collected. Colon weight, histopathologic findings, disease activity index, and the concentration of leukocytes were measured.
Figure 1.
Study design. On days 0 to 8, normal drinking water was replaced with water containing a 3.5% dextran sodium sulfate solution (DSS) for the experimental rats. Healthy rats (negative controls) received normal drinking water or no treatment or anesthesia. On day 3 after induction, experimental rats were randomized into 3 treatment groups, and on days 3-8, they received (1) no treatment or anesthesia; n=17; (2) 4 minutes of sham treatment with anesthesia (n=18); or (3) 4 minutes of lymphatic pump treatment (LPT) with anesthesia (n=18). Nine days after the induction of inflammatory bowel disease, rats were euthanized, and their colons and gastrointestinal lymphoid tissue were collected. Colon weight, histopathologic findings, disease activity index, and the concentration of leukocytes were measured.
Induction of IBD
The DSS murine model was used to induce IBD. On day 0, the rats were randomized into control or experimental groups. Control rats (n=17) received normal drinking water on days 0 to 9 and were included as healthy controls. On days 0 to 9, normal drinking water was replaced with water containing a 3.5% DSS for the experimental groups. On day 3, experimental rats were randomly divided into DSS alone (n=17), DSS+sham (n=18), or DSS+LPT (n=18) groups. Water consumption, weight, and clinical signs of disease were monitored and recorded daily. 
Disease Assessment
Disease severity was monitored daily using the disease activity index (DAI). The DAI score comprises percentage of weight loss, stool consistency, and the presence of blood in the stool. The DAI is a common method for assessing disease severity in the DSS-induced colitis model.20-25 Percentage of weight loss from initial weight on day 0 was scored (0=weight gain or no weight loss; 1=1%-5% weight loss; 2=6%-10% weight loss; 3=11%-20% weight loss; and 4=>20% weight loss), and stool consistency was also scored (0=well-formed pellets; 2=loose stools; and 4=diarrhea). The guaiac paper test using a hemoccult rapid test kit was used to assess the amount of blood in the stool (0=negative; 1=faintly blue; 2=moderately blue; 3=dark blue; and 4=blood visible). The mean score of percentage of weight loss, stool consistency, and presence of blood were used to determine the overall DAI score. 
The proximal and distal section of the large intestine (colon and rectum) was processed and evaluated. Colonic tissues were scored for changes in inflammation, crypt loss, edema, erosion/ulceration, and hyperplasia. The histologic damage was scored as 0, normal; 1, mild (1%-25% of the affected); 2, moderate (26%-50% of the area affected); 3, marked (51%-75% of the area affected); and 4, severe (76%-100% of the area affected). The specific criteria used are summarized in Table 1. The histopathologic assessment was performed by a veterinary pathologist who was blinded to the sample groups. 
Table 1.
Histopathologic Scoring of DSS-Induced Colitis in the Intestinal Tissues of Rats
Score
Lesion 1 2 3 4
Inflammation Mild: focal or widely separated multifocal, in lamina propria Moderate: multifocal/segmental, extending to the submucosa Marked: multifocal or locally extensive (large numbers of neutrophils or macrophages), involving submucosa, with or without hemorrhage Severe: diffuse (large numbers of neutrophils or macrophages), transmural with or without hemorrhage
Crypt loss and lamina propria fibrosis 0%-25% area affected 26%-50% area affected 51%-75% area affected 76%-100% area affected
Edema Mild: multifocal and mucosal Moderate: segmental mucosa +/- submucosa Marked: segmental with submucosal involvement Severe: diffuse and transmural
Erosion/ulcers Mild: focal/ multifocal erosions Moderate: multifocal-segmental erosion or multifocal ulcers Marked: diffuse erosion or multifocal-segmental ulcers Severe: diffuse and transmural
Regenerative hyperplasia/ atypia 2× normal crypts with no goblet cell loss 2×-3× normal crypts with mild goblet cell loss >4× normal crypts, marked goblet cell loss >4× normal crypts, complete goblet cell loss with arborization of crypts

Abbreviations: DSS, dextran sodium sulfate.

Table 1.
Histopathologic Scoring of DSS-Induced Colitis in the Intestinal Tissues of Rats
Score
Lesion 1 2 3 4
Inflammation Mild: focal or widely separated multifocal, in lamina propria Moderate: multifocal/segmental, extending to the submucosa Marked: multifocal or locally extensive (large numbers of neutrophils or macrophages), involving submucosa, with or without hemorrhage Severe: diffuse (large numbers of neutrophils or macrophages), transmural with or without hemorrhage
Crypt loss and lamina propria fibrosis 0%-25% area affected 26%-50% area affected 51%-75% area affected 76%-100% area affected
Edema Mild: multifocal and mucosal Moderate: segmental mucosa +/- submucosa Marked: segmental with submucosal involvement Severe: diffuse and transmural
Erosion/ulcers Mild: focal/ multifocal erosions Moderate: multifocal-segmental erosion or multifocal ulcers Marked: diffuse erosion or multifocal-segmental ulcers Severe: diffuse and transmural
Regenerative hyperplasia/ atypia 2× normal crypts with no goblet cell loss 2×-3× normal crypts with mild goblet cell loss >4× normal crypts, marked goblet cell loss >4× normal crypts, complete goblet cell loss with arborization of crypts

Abbreviations: DSS, dextran sodium sulfate.

×
Sham Treatment and Lymphatic Pump Technique
The control rats did not receive DSS, anesthesia, or LPT on days 0 to 9. The DSS-alone rats did not receive anesthesia or treatment during days 0 to 8. The DSS+sham rats received 4 minutes of anesthesia daily on days 3 to 8. The DSS+LPT rats received LPT daily with anesthesia administration using inhalational isoflurane on days 3 to 8 as previously described by our laboratory.18-19 During LPT, the operator (A.S.) contacted the ventral side of the animal's abdomen with his hands placed bilaterally below the costodiaphragmatic junction. Pressure was exerted medially and cranially to compress the abdomen until resistance was encountered against the diaphragm, and then the pressure was released. Abdominal compressions were administered at a rate of approximately 1 pump per second for a total of 4 minutes. 
Tissue Collection and Leukocyte Enumeration
All rats were euthanized on day 9, and the colon and gastrointestinal tissues were collected. Intestinal tissue was collected to determine total colon weight, and gut-associated lymphoid tissue was collected to determine the concentration of leukocytes. To measure the total number of total leukocytes in mesenteric lymph nodes and Peyer patches, single-cell suspensions were prepared. Tissues were placed in Roswell Park Memorial Institute (Hyclone wash media with 5% fetal bovine serum), minced, and passed through a nylon mesh filter to prepare cell suspensions. Leukocytes were enumerated using a Hemavet 950 (Drew Scientific). 
Statistical Analysis
Data are presented as mean (SD) from 3 separate experiments. For evaluation of statistical significance, data were subjected to a 1-way analysis of variance followed by a Tukey multiple comparisons test or a repeated measures 2-way analysis of variance followed by a Tukey multiple comparisons test. Statistical analyses were performed with GraphPad Prism version 7 (GraphPad Software). Differences among mean values with P≤.05 were considered statistically significant. 
Results
LPT and DAI Score
The DAI results are summarized in Figure 2. The DAI scores were significantly higher (P<.01) in DSS alone, DSS+sham, and DSS+LPT groups on days 3 to 9 compared with control rats. On day 4, DAI scores were significantly increased in DSS+sham (0.9 [0.1]) and DSS+LPT (1.0 [0.1]) when compared with DSS alone (0.6 [0.1]) (P<.05), suggesting that anesthesia may have affected disease activity. On day 9, DSS+LPT significantly decreased the DAI score compared with DSS alone (P<.01). The DAI score in DSS+LPT rats was reduced on days 8 to 9 compared with DSS+sham; however, the difference was not statistically different (P>.05). Of note, no individual DAI score was higher than 3, which indicated that the rats had mild to moderate disease. 
Figure 2.
The lymphatic pump treatment (LPT) decreased disease activity index (DAI) score. Weight loss, stool consistency, and fecal blood concentration were recorded daily and scored to determine DAI score. Data are presented as mean (SE). (A) Statistical decrease compared with all experimental groups (P<.05); (B) statistical decrease compared with sham and LPT (P<.05); (C) statistical decrease compared with control (P<.05). Abbreviation: DSS, dextran sodium sulfate.
Figure 2.
The lymphatic pump treatment (LPT) decreased disease activity index (DAI) score. Weight loss, stool consistency, and fecal blood concentration were recorded daily and scored to determine DAI score. Data are presented as mean (SE). (A) Statistical decrease compared with all experimental groups (P<.05); (B) statistical decrease compared with sham and LPT (P<.05); (C) statistical decrease compared with control (P<.05). Abbreviation: DSS, dextran sodium sulfate.
The DSS model induced inflammation in the gastrointestinal lymphoid tissues, which led to tissue inflammation, edema, and colon shrinkage.25 On day 9, the colons were removed, weighed, and used for histopathologic evaluation. Compared with control rats (4.9 [0.2] g), the colons of DSS-alone (4.3 [0.3] g), DSS+sham (4.1 [0.2] g), or DSS+LPT (4.3 [0.2] g) rats weighed less; however, this reduction was not statistically significant (P>.05). Pathologic alterations, when present, were almost exclusively noted in the distal sections, and therefore, the distal sections were used for the histopathologic scoring evaluation. There was no pathologic change detected in the proximal or distal sections of the large intestines of healthy rats. Overall, DSS-induced pathologic changes of mild to moderate intensity, and these alterations were often of limited extent (<25% of intestines involved). No statistical differences were found in intestinal histopathologic changes between DSS-alone, DSS+sham, and DSS+LPT groups (P>.05; Table 2). 
Table 2.
Histopathologic Findings and Leukocyte Concentration in the Intestinal Tissues of Control and Experimental Rats
Groupb
Findings Control DSS alone DSS+sham DSS+LPT
Grade/lesiona
 Inflammation 0 1.2 (0.2) 1 (0) 1.2 (0.2)
 Crypt loss and lamina propria fibrosis 0 1 (0) 1.5 (0.5) 1.4 (0.2)
 Edema 0 1 (0) 1 (0) 1.2 (0.4)
 Erosion/ulcers 0 1.4 (0.2) 1 (0) 1.6 (0.3)
 Hyperplasia 0 1.5 (0.5) 0 1 (0)
Total leukocytes ×108
 Mesenteric lymph nodes 1.4 (0.1) 2.4 (0.6) 1.5 (0.5) 1.9 (0.8)
 Peyer patches 1.0 (0.2) 1.6 (0.4) 2.3 (0.5) 2.1 (0.6)

a Large intestines were excised and scored using histopathologic grading of colitis. Mesenteric lymph nodes and Peyer patches were removed, and the total concentration of leukocytes was quantified.

b Data are presented as mean (SD).

Abbreviations: DSS, dextran sodium sulfate; LPT, lymphatic pump treatment.

Table 2.
Histopathologic Findings and Leukocyte Concentration in the Intestinal Tissues of Control and Experimental Rats
Groupb
Findings Control DSS alone DSS+sham DSS+LPT
Grade/lesiona
 Inflammation 0 1.2 (0.2) 1 (0) 1.2 (0.2)
 Crypt loss and lamina propria fibrosis 0 1 (0) 1.5 (0.5) 1.4 (0.2)
 Edema 0 1 (0) 1 (0) 1.2 (0.4)
 Erosion/ulcers 0 1.4 (0.2) 1 (0) 1.6 (0.3)
 Hyperplasia 0 1.5 (0.5) 0 1 (0)
Total leukocytes ×108
 Mesenteric lymph nodes 1.4 (0.1) 2.4 (0.6) 1.5 (0.5) 1.9 (0.8)
 Peyer patches 1.0 (0.2) 1.6 (0.4) 2.3 (0.5) 2.1 (0.6)

a Large intestines were excised and scored using histopathologic grading of colitis. Mesenteric lymph nodes and Peyer patches were removed, and the total concentration of leukocytes was quantified.

b Data are presented as mean (SD).

Abbreviations: DSS, dextran sodium sulfate; LPT, lymphatic pump treatment.

×
DSS Did Not Induce Inflammation in Gastrointestinal Lymphoid Tissues
To determine the effect of LPT and IBD on the concentration of gastrointestinal leukocytes, mesenteric lymph nodes and Peyer patches were collected on day 9. There were no significant differences (P>.05) in total leukocyte concentrations in mesenteric lymph nodes of control, DSS-alone, DSS+sham, or DSS+LPT rats. Similarly, there were no significant differences (P>.05) in total leukocyte concentrations in Peyer patches among all groups (Table 2). 
Discussion
In this preliminary study, the rats had mild, acute IBD. Compared with DSS-alone rats, rats that received abdominal DSS+LPT had decreased DAI scores. While DSS+LPT reduced disease compared with DSS+sham, the decrease was not statistically significant, which suggested that the combination of LPT and anesthesia had a protective effect on IBD pathogenesis. 
We hypothesized that abdominal LPT would protect against IBD by reducing intestinal inflammation, yet, there were no differences in colon weight, colon histopathologic findings, or leukocyte concentration in the gastrointestinal lymphoid tissue between DSS-alone, DSS+sham, or DSS+LPT rats. Inflammatory bowel disease was mild to moderate in this study, which could explain, in part, the lack of significant changes in the DAI scores and inflammation. Considering that DSS+sham was the control for DSS+LPT, statistical differences should have been demonstrated between these 2 experimental groups. Future studies should examine the effect of LPT on rats with more robust signs of severe acute and chronic IBD. Under these conditions, abdominal LPT might have a more notable effect on disease progression. 
We acknowledge that the OMT applied to the rat differs from the OMT used to treat patients with IBS and IBD, which is a limitation of this study. Additionally, patients would likely receive medications for IBD. Therefore, future studies should examine whether LPT acts in synergy with medications used in the treatment of IBD. 
Conclusion
Abdominal LPT marginally improved disease severity in rats with mild IBD. To identify the optimal effect of LPT on IBD, future studies should include animals with more severe acute and chronic IBD. Considering the growing use of adjunctive treatment for the management of IBD, it is important to identify the effect of OMT on IBD progression. Studies such as these are important for identifying the mechanism of action of OMT during the treatment of IBD. 
Author Contributions
Drs Schander, Castillo, and Hodge provided substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; all authors drafted the article or revised it critically for important intellectual content; all authors gave final approval of the version of the article to be published; and all authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. 
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Figure 1.
Study design. On days 0 to 8, normal drinking water was replaced with water containing a 3.5% dextran sodium sulfate solution (DSS) for the experimental rats. Healthy rats (negative controls) received normal drinking water or no treatment or anesthesia. On day 3 after induction, experimental rats were randomized into 3 treatment groups, and on days 3-8, they received (1) no treatment or anesthesia; n=17; (2) 4 minutes of sham treatment with anesthesia (n=18); or (3) 4 minutes of lymphatic pump treatment (LPT) with anesthesia (n=18). Nine days after the induction of inflammatory bowel disease, rats were euthanized, and their colons and gastrointestinal lymphoid tissue were collected. Colon weight, histopathologic findings, disease activity index, and the concentration of leukocytes were measured.
Figure 1.
Study design. On days 0 to 8, normal drinking water was replaced with water containing a 3.5% dextran sodium sulfate solution (DSS) for the experimental rats. Healthy rats (negative controls) received normal drinking water or no treatment or anesthesia. On day 3 after induction, experimental rats were randomized into 3 treatment groups, and on days 3-8, they received (1) no treatment or anesthesia; n=17; (2) 4 minutes of sham treatment with anesthesia (n=18); or (3) 4 minutes of lymphatic pump treatment (LPT) with anesthesia (n=18). Nine days after the induction of inflammatory bowel disease, rats were euthanized, and their colons and gastrointestinal lymphoid tissue were collected. Colon weight, histopathologic findings, disease activity index, and the concentration of leukocytes were measured.
Figure 2.
The lymphatic pump treatment (LPT) decreased disease activity index (DAI) score. Weight loss, stool consistency, and fecal blood concentration were recorded daily and scored to determine DAI score. Data are presented as mean (SE). (A) Statistical decrease compared with all experimental groups (P<.05); (B) statistical decrease compared with sham and LPT (P<.05); (C) statistical decrease compared with control (P<.05). Abbreviation: DSS, dextran sodium sulfate.
Figure 2.
The lymphatic pump treatment (LPT) decreased disease activity index (DAI) score. Weight loss, stool consistency, and fecal blood concentration were recorded daily and scored to determine DAI score. Data are presented as mean (SE). (A) Statistical decrease compared with all experimental groups (P<.05); (B) statistical decrease compared with sham and LPT (P<.05); (C) statistical decrease compared with control (P<.05). Abbreviation: DSS, dextran sodium sulfate.
Table 1.
Histopathologic Scoring of DSS-Induced Colitis in the Intestinal Tissues of Rats
Score
Lesion 1 2 3 4
Inflammation Mild: focal or widely separated multifocal, in lamina propria Moderate: multifocal/segmental, extending to the submucosa Marked: multifocal or locally extensive (large numbers of neutrophils or macrophages), involving submucosa, with or without hemorrhage Severe: diffuse (large numbers of neutrophils or macrophages), transmural with or without hemorrhage
Crypt loss and lamina propria fibrosis 0%-25% area affected 26%-50% area affected 51%-75% area affected 76%-100% area affected
Edema Mild: multifocal and mucosal Moderate: segmental mucosa +/- submucosa Marked: segmental with submucosal involvement Severe: diffuse and transmural
Erosion/ulcers Mild: focal/ multifocal erosions Moderate: multifocal-segmental erosion or multifocal ulcers Marked: diffuse erosion or multifocal-segmental ulcers Severe: diffuse and transmural
Regenerative hyperplasia/ atypia 2× normal crypts with no goblet cell loss 2×-3× normal crypts with mild goblet cell loss >4× normal crypts, marked goblet cell loss >4× normal crypts, complete goblet cell loss with arborization of crypts

Abbreviations: DSS, dextran sodium sulfate.

Table 1.
Histopathologic Scoring of DSS-Induced Colitis in the Intestinal Tissues of Rats
Score
Lesion 1 2 3 4
Inflammation Mild: focal or widely separated multifocal, in lamina propria Moderate: multifocal/segmental, extending to the submucosa Marked: multifocal or locally extensive (large numbers of neutrophils or macrophages), involving submucosa, with or without hemorrhage Severe: diffuse (large numbers of neutrophils or macrophages), transmural with or without hemorrhage
Crypt loss and lamina propria fibrosis 0%-25% area affected 26%-50% area affected 51%-75% area affected 76%-100% area affected
Edema Mild: multifocal and mucosal Moderate: segmental mucosa +/- submucosa Marked: segmental with submucosal involvement Severe: diffuse and transmural
Erosion/ulcers Mild: focal/ multifocal erosions Moderate: multifocal-segmental erosion or multifocal ulcers Marked: diffuse erosion or multifocal-segmental ulcers Severe: diffuse and transmural
Regenerative hyperplasia/ atypia 2× normal crypts with no goblet cell loss 2×-3× normal crypts with mild goblet cell loss >4× normal crypts, marked goblet cell loss >4× normal crypts, complete goblet cell loss with arborization of crypts

Abbreviations: DSS, dextran sodium sulfate.

×
Table 2.
Histopathologic Findings and Leukocyte Concentration in the Intestinal Tissues of Control and Experimental Rats
Groupb
Findings Control DSS alone DSS+sham DSS+LPT
Grade/lesiona
 Inflammation 0 1.2 (0.2) 1 (0) 1.2 (0.2)
 Crypt loss and lamina propria fibrosis 0 1 (0) 1.5 (0.5) 1.4 (0.2)
 Edema 0 1 (0) 1 (0) 1.2 (0.4)
 Erosion/ulcers 0 1.4 (0.2) 1 (0) 1.6 (0.3)
 Hyperplasia 0 1.5 (0.5) 0 1 (0)
Total leukocytes ×108
 Mesenteric lymph nodes 1.4 (0.1) 2.4 (0.6) 1.5 (0.5) 1.9 (0.8)
 Peyer patches 1.0 (0.2) 1.6 (0.4) 2.3 (0.5) 2.1 (0.6)

a Large intestines were excised and scored using histopathologic grading of colitis. Mesenteric lymph nodes and Peyer patches were removed, and the total concentration of leukocytes was quantified.

b Data are presented as mean (SD).

Abbreviations: DSS, dextran sodium sulfate; LPT, lymphatic pump treatment.

Table 2.
Histopathologic Findings and Leukocyte Concentration in the Intestinal Tissues of Control and Experimental Rats
Groupb
Findings Control DSS alone DSS+sham DSS+LPT
Grade/lesiona
 Inflammation 0 1.2 (0.2) 1 (0) 1.2 (0.2)
 Crypt loss and lamina propria fibrosis 0 1 (0) 1.5 (0.5) 1.4 (0.2)
 Edema 0 1 (0) 1 (0) 1.2 (0.4)
 Erosion/ulcers 0 1.4 (0.2) 1 (0) 1.6 (0.3)
 Hyperplasia 0 1.5 (0.5) 0 1 (0)
Total leukocytes ×108
 Mesenteric lymph nodes 1.4 (0.1) 2.4 (0.6) 1.5 (0.5) 1.9 (0.8)
 Peyer patches 1.0 (0.2) 1.6 (0.4) 2.3 (0.5) 2.1 (0.6)

a Large intestines were excised and scored using histopathologic grading of colitis. Mesenteric lymph nodes and Peyer patches were removed, and the total concentration of leukocytes was quantified.

b Data are presented as mean (SD).

Abbreviations: DSS, dextran sodium sulfate; LPT, lymphatic pump treatment.

×