Foundations and Mechanisms of DSS-Induced
Colitis
Fundamentals of Inflammatory Bowel Disease (IBD)
Inflammatory bowel disease (IBD) is a complex and multifactorial chronic inflammatory
disorder of the gastrointestinal tract, with Crohn’s disease
(CD) and Ulcerative colitis (UC) being its two
main subtypes. Over the years, despite extensive research efforts, the pathogenesis of
IBD remains incompletely understood. This has led to the development and implementation
of numerous animal models to simulate the disease process and investigate its underlying
mechanisms.
These models can be primarily divided into four categories: chemically induced,
genetically engineered, T cell transfer, and spontaneous gene mutation
models[2].
Table 1. Synopsis for numerous IBD models[2].
Owing to its high reproducibility, ease of generation and maintenance,
and the ability to mimic many critical features of human IBD, DSS has become one of the most common and effective chemical
inducers for colitis.
The Mechanisms of DSS-Induced Colitis
DSS is a water soluble, negatively charged polysaccharide with a highly variable
molecular weight that typically ranges from 5-1,400 kDa. It is an α-D-(1→6) linear
glucan with 2 sulfate groups on each α-glucose unit, and its degree of sulfation is 16%
to 19%[3]. Currently, It is generally considered that 36-50 kDa is the
optimal molecular weight range of DSS for establishing colitis models. Smaller DSS molecules weaken their pro-inflammatory effect, while exceeding this molecular weight range reduces their ability to penetrate colonic tissues, both of which affect the
modeling effect[4].
Figure 1. Chemical structure of DSS[3].
As a water-soluble sulfated polysaccharide, DSS directly disrupts the tight junctions
between intestinal epithelial cells, impairing barrier integrity. The impairment of
colonic epithelial barrier function allows luminal bacteria, viruses, and associated
antigens to enter the mucosa. Together with the entry of DSS itself, these pathogens
could trigger inflammatory responses. This process involves pathways such as Toll-like receptors, NLRP3
inflammasomes, as well as the release of various inflammatory mediators[3].
At the acute stage of DSS-induced colitis, inflammation develops dependent on innate
immunity mediated by cells such as macrophages and neutrophils, and does not rely on T
cell-mediated adaptive immunity. Inflammatory mediators produced via mechanisms of
innate immunity are sufficient to cause acute colitis and tissue. As DSS treatment is
continued, the secretion of these inflammatory mediators increases progressively. While
a steady upregulation of Th1 cytokines (TNF-α, IFN-γ, IL-1, and IL-12) characterizes the acute phase of colitis, the chronic
phase of DSS-induced colitis involves Th2-mediated inflammatory mediators (IL-4, IL-6, and IL-10). In addition, the intestinal flora plays an important
role in DSS-induced colitis, and its presence exacerbates inflammation[3].
Figure 2. Schematic representation of DSS-induced colitis[3].
In summary, DSS-induced colitis is the result of the combined action of multiple factors
such as its physicochemical properties, impaired intestinal barrier function, immune
activation, and intestinal microbiota, ultimately leading to the occurrence and
progression of colonic tissue damage and inflammation.
Given these characteristics, DSS can serve as a versatile experimental tool to establish
colitis-associated models either alone or in combination with other carcinogens, thereby
recapitulating the key features of IBD. The following sections provide detailed
descriptions of various DSS-based models, including their induction protocols and
recommended biomarkers for disease monitoring.
Establishment and Precautions of DSS Colitis Models
The Types and Methods of DSS-Induced Colitis
DSS serves as a dual-purpose model inducer: alone, it triggers acute/chronic colitis
via epithelial barrier disruption and immune activation; in combination with
carcinogens (e.g., Azoxymethane), it recapitulates
colitis-associated colorectal cancer (CAC) with distal colon tumorigenesis. Table 2
summarizes recommended protocols for three disease models, including dosing cycles
and validation metrics.
Table 2. Guidelines for DSS-induced colitis (Recommended
DSS MW of 35,000-45,000).
Figure 3.Experimental periods of different DSS (36-50 kDa)-induced colitis models.
Generally, when assessing the DSS-induced colitis model, the disease activity
index (DAI) score is calculated. A higher score indicates more pronounced
inflammation, that is, a better induction effect[3].
Table 3. Scoring system of disease activity index (DAI)[3][10].
The Precautions of DSS Model Establishment
In DSS-induced colitis models, multiple factors can influence the efficacy of model
establishment. The ideal dosage and administration method depends on your study,
animal model, and the genetic background of your animals. We have compiled some
precautions for your reference.
36-50 kDa is the optimal molecular weight range of DSS for colitis model
creation. Low molecular weight DSS has a weaker inflammatory effect, and higher
molecular weight DSS will not absorb as easily.
The concentration of the DSS solution, the species and strain of the animals may all
affect the effect of model establishment. The optimal age range for successfully and
easily repeating the DSS colitis is 6 to 8 weeks, and male mice may be
more sensitive than female mice[11-13]. BALB/c and C57BL/6
mice are the most widely used inbred strains, and CD-1 is a commonly used
outbred mouse strain[3].
It is recommended to replace the drinking water containing DSS every 1-2 days during
the modeling period. The water intake can be calculated according to 7-10 mL per day
for mice and 11 mL/100 g of body weight per day for rats. Ensure that there is no
blockage or leakage in the water bottle.
In order to clearly observe model development, it is necessary to record the
water intake, body weight, and disease phenotype every day. For
pathological sections, it is recommended to take a 1-2 cm segment near the
anus.
In order to reduce the difference in water intake, it is recommended to house 2-3
animals in each cage, and no more than 5 animals per cage. Keep the animal habitat,
diet and husbandry consistent and optimal.
These standardized housing and management practices are essential to minimize
experimental variability, ensuring the reliability of DSS-induced colitis models for
therapeutic studies.
Clinical Validation and Expanded Applications of DSS
Clinical Validation of DSS-Derived IBD Therapies
While preclinical DSS models have elucidated key IBD pathogenesis mechanisms, their
ultimate translational value lies in guiding clinically effective therapies. Colitis
induced by DSS reproduces some of the key features of human IBD, including
inflammation, diarrhea, and abnormal feces. Since its introduction, the DSS-induced
colitis model has been widely utilized in research to investigate and evaluate
potential therapies for IBD, with its application culminating in the successful
development of several drugs[3].
Table 4. Therapies tested in DSS-induced model and their fates in the clinical
trials[3].
Beyond their translational impact in IBD therapy, recent studies have highlighted
that the biological properties of DSS are strongly influenced by its molecular
weight, expanding its applications into broader biomedical and material sciences.
Molecular Weight Spectrum of DSS: Beyond Colitis Modeling
The biological effects of DSS are intrinsically linked to its molecular weight,
which determines not only colitis induction but also broader research applications.
Currently, it is generally considered that 36-50 kDa is the optimal molecular weight
range of DSS for establishing colitis models. DSS of other molecular weights also
exhibit additional activities, such as antiviral and coagulant effects, and have
applications in research areas including material modification and drug delivery.
Table 5. The research of DSS with different molecular weights.
Summary
DSS-induced colitis results from its physicochemical properties, disruption of the
intestinal epithelial barrier, immune activation, and interactions with the gut
microbiota. Inflammation progresses rapidly, primarily affecting epithelial cells,
and involves innate immune responses initially, with adaptive immunity contributing
later. While DSS models mainly mimic ulcerative colitis rather than Crohn’s disease,
they provide critical insights into IBD pathogenesis, inflammatory pathways, and
disease mechanisms.
DSS models are widely used due to their reproducibility, accessibility, and
flexibility in inducing acute or chronic colitis by adjusting dosage,
administration, and DSS molecular weight. Careful selection of animal strain, age,
sex, and experimental conditions ensures reliable outcomes. Preclinical DSS studies
have guided the development of multiple IBD therapies, demonstrating translational
value, and research on DSS molecular weight highlights its broader biological
applications, from antiviral and coagulation effects to material science. Overall,
DSS models offer an indispensable platform for mechanistic studies, optimized
modeling, and translational research in IBD.
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