FAQs About DSS-Induced Colitis Modeling

Dextran Sulfate Sodium Salt (DSS) is a sulfated polysaccharide commonly used to induce ulcerative colitis (UC) in experimental animals. While the exact mechanism of DSS-induced colitis remains unclear, it is generally believed to involve macrophage dysfunction, gut microbiota imbalance, epithelial toxicity, and abnormal cytokine activity. Together, these effects trigger inflammatory responses that closely resemble human UC, making DSS a well-established reagent for modeling inflammatory bowel disease (IBD). Today, let’s take a deep dive into the most frequently asked questions about DSS preparation, experimental procedures, and result interpretation.

I. Reagent Preparation

Q1: How should DSS solution be prepared? What type of water should be used? Should it be sterilized or filtered?

A1: Dissolve DSS in sterile distilled water (autoclaved water). There is no need for ultrasonic treatment. After the DSS is completely dissolved, filter the solution through a 0.22 μm membrane filter before use. It’s recommended to prepare fresh DSS solution daily.

Q2: Can DSS be sterilized by autoclaving?

A2: No. Autoclaving alters the molecular structure of DSS, which can reduce its biological activity and affect model reproducibility.

II. About operation

Q1: What are the administration routes for DSS-induced colitis modeling?

A1: Free drinking, oral administration, or gavage.

Q2: What are the key factors affecting the success of DSS modeling?

A2: DSS concentration, molecular weight, administration time and animal species.

Q3: What DSS concentrations and durations are used for acute and chronic colitis models in mice?

A3:

• Acute model: 3–5% DSS in drinking water, administered for approximately 7 days.
• Chronic model: 1–3% DSS with intermittent cycles, typically lasting around 9 weeks.

[Note]: The optimal concentration depends on several factors, including species, strain, body weight, and administration method. It’s strongly recommended to consult published protocols and conduct pilot studies to determine the best conditions for your model.

Q4: How is DSS administered by gavage for colitis modeling?

A4: Administer a 2% DSS solution via gavage at 10:00 AM, 2:00 PM, and 6:00 PM daily. Each dose should be 30 mL/kg, and no additional water is needed during this period. After each gavage, provide sufficient quantities of mixed-formula pellet feed, then remove the feed at 8:00 AM the following day. The modeling protocol can be carried out for up to 9 consecutive days.

Reference: Comparative study of free drinking of dextran sulfate sodium for quantitative gavage-induced acute colitis model in mice, Gastroenterology (2009), 14(1): 27–30.

Q5: How much water do rats and mice consume daily during DSS-induced colitis modeling?
A5:

• Mice (20–25 g): ~7–10 mL per day
• Rats (100 g): ~10–11  mL per day

These values are averages and may vary based on health status, ambient temperature, and feed composition.

III. Result Analysis

By providing animals with DSS (MW: 36,000–50,000) in drinking water at varying concentrations and durations, researchers can establish acute or chronic colitis models.

These models reproduce clinical and pathological features similar to human UC, such as:

• Diarrhea and mucus-like stools
• Occult or visible blood in feces
• Weight loss and reduced mobility
• Poor coat condition and general malaise

Table 1. Histological Characteristics of DSS-Induced Colitis Models

Model Type	Acute Colitis Model	Chronic Colitis Model
Colon morphology	Congestion, edema, shortened and fragile colon, increased weight-to-length ratio	Markedly shortened colon
Ulceration	Ulcers of varying severity	Mucosal thickening, lymph node enlargement
Mucosal changes	Edema, goblet cell loss, crypt swelling and destruction	Goblet cell and crypt loss
Inflammation	Infiltration of inflammatory cells, epithelial damage	Possible adenomatous polyps or tumor-like lesions

Q1: How to Evaluate Modeling Success ?

A1. Disease Activity Index (DAI Score)

The DAI score is based on body weight loss, stool consistency, and occult blood. Each parameter is scored from 0 to 4, and the total represents disease severity.

A2. Histological Scoring (HE Staining)

Histological evaluation is a key indicator of inflammation and tissue damage.

Score	Ulcers (count)	Epithelial Changes	Inflammatory Infiltration	Lymph Nodes (count)
0	0	Normal	None	None
1	1	Goblet cell loss	Pericrypt infiltration	1
2	2	Extensive goblet cell loss	Mucosal muscle infiltration	2
3	3	Crypt loss	Diffuse mucosal infiltration and thickening	3
4	>3	Crypt loss or polyp-like regeneration	Submucosal infiltration	>3

A3. Colon Length Measurement

In acute colitis, colon shortening becomes noticeable around day 8, while in chronic models, the reduction is more pronounced. 

Figure 1. Comparison of colon length between control and DSS-treated groups showing significant shortening in DSS-induced colitis rats.

IV. Troubleshooting DSS-Induced Colitis: Common Issues and Practical Solutions

Q1: What are the common reasons for failure in DSS-induced colitis modeling?

A1: Several factors can influence the success of colitis induction using DSS, including:

• Animal-related variables: Species, strain, gender, and weight all affect susceptibility. Mice, rats, hamsters, and guinea pigs can all be used, but responses differ significantly.
• DSS properties: Molecular weight and sulfur content impact effectiveness. Lower sulfur content or higher molecular weight DSS often results in poor modeling outcomes.

Recommended best practices:

1)Use mice aged 6–8 weeks and weighing ≥18 g.

2)Maintain uniformity in gender, strain, and body weight.

3)House 3–5 mice per cage to reduce variability.

4)Ensure DSS solutions are fresh, homogeneous, and freely accessible.

5)Source DSS from reliable suppliers with batch consistency.ColitCare™ Dextran Sulfate Sodium (DSS), Colitis Grade MW:36000~50000

Q2: Why is there a high mortality rate in DSS-treated mice?

A2: High mortality is often caused by: Excessive DSS concentration; Prolonged administration period

Solution:

• Lower DSS concentration to 1–2% for acute colitis modeling.
• Shorten the exposure duration to 4–7 days, as supported by literature.

Q3: Why is 36–50 kDa DSS typically used for colitis modeling?

A3: DSS molecular weight impacts solubility and mucosal permeability, which are critical for effective colitis induction.

• 36–50 kDa DSS strikes a balance between permeability and solubility.
• Low MW DSS (<10 kDa): High permeability but may induce systemic toxicity.
• High MW DSS (>500 kDa): Poor solubility and ineffective penetration.

Always refer to published studies and pilot tests to select the appropriate molecular weight based on your model and research objectives.

Q4: Mice consumed 3% DSS for three days but showed no significant weight loss. Is that normal?

A4: Yes, some animals may have delayed onset of symptoms. Weight loss may not begin until day 5 or later.

If no symptoms are observed by day 7, consider increasing the concentration to 3.5–5% DSS.

Q5: In acute colitis modeling, why doesn’t the colon shorten, and why is the cecum enlarged?

A5: Colon shortening is more pronounced in chronic colitis. In acute models, symptoms include:

• Fragile, congested, and translucent colonic tissue
• Cecal enlargement due to inflammatory congestion and edema

Confirmation should rely on histopathological evaluation (e.g., H&E staining) rather than gross anatomy alone.

Q6: Is small intestinal bleeding normal after DSS treatment?

A6: Mild bleeding may occur with high DSS concentrations and is generally not harmful.

If bleeding is excessive, reduce the DSS concentration to avoid damage beyond the colon.

Q7: Mice showed significant weight loss, but no inflammation was observed in H&E staining. Why?

A7: DSS must reach a threshold level to induce visible inflammation.

Weight loss without histological inflammation suggests sub-threshold exposure. Extend the DSS cycle or slightly increase the dose.

Q8: Why do mice in the same cage exhibit different symptoms?

A8: Variability in symptoms is often due to:

• Individual differences in DSS tolerance
• Unequal water consumption

These factors can lead to inconsistent symptom severity, even under the same conditions.

 

For more details, visit the DSS ColitCare™ product page: ColitCare™ Dextran Sulfate Sodium (DSS), Colitis Grade MW:36000~50000