Establishment and Evaluation of Animal Models of Gastric Ulcer: Chemical Induction, Stress Injury, Infection Models, and Healing Studies
Establishment and Evaluation of Animal Models of Gastric Ulcer: Chemical Induction, Stress Injury, Infection Models, and Healing Studies
Animal models of gastric ulcer are used to simulate gastric mucosal barrier disruption, acid-related injury, inflammatory infiltration, oxidative stress, and ulcer repair processes. Model selection should be centered on the research objective: ethanol- or NSAID-induced models are commonly used for acute mucosal protection studies, acetic acid-induced models are often used for chronic healing studies, pylorus ligation models are suitable for acid secretion mechanisms, and Helicobacter pylori infection models are required for infection-related mechanisms.
Keywords: gastric ulcer model; animal modeling; ethanol induction; NSAIDs; acetic acid ulcer; stress ulcer; Helicobacter pylori; gastric mucosal injury
1 Experimental Positioning of Gastric Ulcer Models
1.1 Core Objectives of Model Establishment
(1) Acute gastric mucosal injury
Acute models mainly focus on gastric mucosal barrier disruption, hemorrhagic erosion, oxidative stress, and increased inflammatory factors. Ethanol, indomethacin, aspirin, and stress stimulation can all induce gastric mucosal injury within a short period, making these models suitable for evaluating the gastric mucosal protective effects of candidate drugs.
(2) Chronic ulcer repair
Chronic models focus more on re-epithelialization at the ulcer margin, granulation tissue formation, angiogenesis, and tissue remodeling. The acetic acid-induced model can form chronic ulcer lesions with relatively stable boundaries and is suitable for studying mechanisms related to EGF, VEGF, collagen deposition, and mucosal repair.
(3) Etiology-related mechanisms
Different models correspond to different pathogenic mechanisms. NSAID models emphasize inhibition of prostaglandin synthesis and reduced mucosal defense; pylorus ligation models highlight the effects of gastric acid and pepsin; ischemia-reperfusion models emphasize oxidative stress and microcirculatory disturbance; Helicobacter pylori infection models are used to analyze infection, inflammation, and chronic mucosal lesions.
1.2 Experimental Animals and Model Selection
Rats and mice are the most commonly used animals for gastric ulcer modeling. Sprague-Dawley and Wistar rats are commonly used for ulcer area measurement, gastric juice analysis, and histological evaluation. Mice are suitable for mechanistic studies, genetically modified models, and infection-related immune analysis. Mongolian gerbils are more sensitive to chronic Helicobacter pylori infection and gastric pathological changes, and can be used for studies of infection-related gastric diseases.
Table 1 Selection Logic for Animal Models of Gastric Ulcer
Research Objective | Recommended Model | Main Mechanism | Applicable Evaluation Indicators |
Evaluation of acute mucosal protection | Ethanol-induced model | Mucosal barrier disruption, hemorrhagic injury, oxidative stress | Ulcer index, MDA, SOD, HE staining |
NSAID-related gastric injury research | Indomethacin or aspirin model | Decreased prostaglandins, weakened mucus barrier, inflammatory response | PGE2, MPO, TNF-α, IL-6 |
Chronic ulcer healing mechanisms | Acetic acid-induced model | Local tissue necrosis, chronic inflammation, repair and remodeling | Ulcer area, EGF, VEGF, collagen deposition |
Stress ulcer research | Water immersion restraint or cold restraint model | Neuroendocrine stress, reduced mucosal blood flow | Ulcer index, gastric mucosal blood flow, oxidative stress |
Acid secretion-related injury | Pylorus ligation model | Accumulation of gastric acid and pepsin | Gastric juice volume, pH, total acidity, pepsin activity |
Infection-related ulcer research | Helicobacter pylori infection model | Chronic inflammation, bacterial colonization, epithelial injury | Bacterial load, inflammation score, IL-1β, TNF-α |
Microcirculatory disturbance and oxidative injury | Ischemia-reperfusion model | Blood flow obstruction, increased ROS, inflammatory infiltration | MDA, SOD, MPO, tissue necrosis area |
2 Chemically Induced Gastric Ulcer Models
2.1 Ethanol-Induced Model
(1) Model mechanism
Ethanol can rapidly disrupt the gastric mucus layer and epithelial barrier, allowing gastric acid, oxidative stress, and inflammatory responses to jointly cause mucosal hemorrhage, necrosis, and erosion. This model mainly presents as acute gastric mucosal injury and is suitable for evaluating antioxidant, anti-inflammatory, and mucosal protective drugs.
(2) Experimental interpretation
In the ethanol model, ulcer area and hemorrhagic bands are relatively intuitive, but the degree of injury is significantly affected by ethanol concentration, administration volume, fasting time, and animal body weight. If the model is used for drug screening, positive control, model control, and pretreatment groups should be included, and oxidative stress and histological indicators should be measured simultaneously.
2.2 NSAID-Induced Model
(1) Model mechanism
NSAIDs such as indomethacin and aspirin can inhibit the cyclooxygenase pathway, reduce prostaglandin production, and weaken gastric mucus secretion, bicarbonate secretion, and mucosal blood flow. This model is more closely related to gastric mucosal injury associated with long-term NSAID use.
(2) Experimental interpretation
In NSAID models, decreased PGE2, increased inflammatory factors, and reduced gastric mucosal defense capacity are important interpretation points. When studying the gastroprotective effects of candidate drugs, ulcer index, PGE2, MPO, TNF-α, IL-6, and gastric mucus content should be observed together to avoid inferring the mechanism solely from ulcer area.
2.3 Acetic Acid-Induced Chronic Ulcer Model
(1) Model mechanism
After local application of acetic acid to the gastric wall, a chronic ulcer lesion with a relatively clear boundary can be formed, followed by inflammatory clearance, granulation tissue formation, angiogenesis, and epithelial repair. This model is more suitable for studying ulcer healing than acute mucosal protection.
(2) Experimental interpretation
Core evaluation indicators in the acetic acid model include reduction in ulcer area, mucosal re-epithelialization, collagen deposition, angiogenesis, and growth factor expression. Changes in EGF, VEGF, TGF-β, COX-2, and tight junction proteins can be used to assess the quality of repair.
Table 2 Comparison of Chemically Induced Gastric Ulcer Models
Model Type | Common Inducer | Main Pathological Features | Advantages | Limitations |
Ethanol-induced model | Ethanol | Acute hemorrhage, erosion, mucosal necrosis | Rapid modeling; suitable for screening mucosal protective drugs | Injury is mainly acute, with insufficient chronic repair features |
NSAID-induced model | Decreased prostaglandins, enhanced inflammatory response, impaired mucosal barrier | Close to NSAID-related gastric injury | Sensitive to dose, fasting status, and administration route | |
NSAID-induced model | Reduced gastric mucosal defense, acid-related injury, and inflammatory response | Suitable for drug-induced gastric mucosal injury research | Model intensity is affected by dose and administration period | |
Acetic acid chronic model | Chronic ulcer, marginal repair, granulation tissue formation | Suitable for studying ulcer healing mechanisms | More complex operation and high requirement for consistency of local treatment | |
Acid injury-related model | Hydrochloric acid | Acidic stimulation, barrier disruption, and local mucosal injury | Can be used to simulate acid-related injury conditions | Still differs from complex ulcer etiologies when used alone |
3 Stress-, Infection-, and Surgery-Related Models
Water immersion restraint stress causes decreased mucosal blood flow, altered gastric acid secretion, and enhanced oxidative stress through combined activity restriction, cold stimulation, and sympathetic activation. This model is suitable for studying stress ulcers, neuroendocrine regulation, and gastric mucosal microcirculatory injury.
(2) Cold restraint stress model
Cold restraint stress emphasizes the combined stimulation of low temperature and restraint, and is often used to observe gastric mucosal injury under acute stress conditions. Temperature, restraint duration, and animal status should be strictly controlled during experiments to reduce intra-group variation.
3.2 Pylorus Ligation Model
The pylorus ligation model blocks gastric emptying, causing gastric acid and pepsin to accumulate in the stomach and induce acid-related ulcers. This model is suitable for studying gastric acid secretion, pepsin activity, and the effects of antacid drugs. Result evaluation should include gastric juice volume, pH, total acidity, and pepsin activity, not only ulcer area.
3.3 Ischemia-Reperfusion Model
The ischemia-reperfusion model induces oxidative stress, inflammatory cell infiltration, and microcirculatory disturbance through gastric blood flow obstruction followed by reperfusion. This model is suitable for studying ROS, mitochondrial injury, endothelial function, and inflammation-mediated gastric mucosal injury. MDA, SOD, GSH, MPO, and tissue necrosis area are commonly used evaluation indicators.
3.4 Helicobacter pylori Infection Model
The Helicobacter pylori infection model is used to simulate infection-related gastritis, mucosal injury, and ulcer susceptibility. Common strains include H. pylori SS1, and animals may include mice or Mongolian gerbils. This model requires a relatively long period and should be evaluated by bacterial colonization detection, inflammation scoring, histological observation, and inflammatory factor analysis.
Table 3 Comparison of Stress-, Infection-, and Surgery-Related Gastric Ulcer Models
Model Type | Modeling Characteristics | Main Mechanism | Suitable Research Direction | Key Control Points |
Water immersion restraint stress model | Restraint combined with water immersion stimulation | Decreased mucosal blood flow and neuroendocrine stress | Stress ulcer and microcirculatory injury | Water temperature, restraint duration, animal status |
Cold restraint stress model | Restraint combined with low-temperature stimulation | Sympathetic activation and oxidative stress | Acute stress injury | Temperature and exposure duration |
Pylorus ligation model | Surgical blockage of gastric emptying | Accumulation of gastric acid and pepsin | Acid secretion and antacid drug evaluation | Ligation site and postoperative observation time |
Ischemia-reperfusion model | Reperfusion after blood flow obstruction | Increased ROS, inflammatory infiltration, microcirculatory disturbance | Oxidative stress and blood flow-related injury | Ischemia duration and reperfusion duration |
Helicobacter pylori infection model | Long-term infection after bacterial inoculation | Chronic inflammation, bacterial colonization, epithelial injury | Infection-related gastric disease mechanisms | Bacterial viability, inoculation frequency, infection period |
4 Supplementary Applications of In Vitro and Ex Vivo Models
4.1 Gastric Epithelial Cell Injury Models
Gastric epithelial cells such as GES-1 and AGS can be used for studies of H₂O₂-, ethanol-, NSAID-, or inflammation-induced cell injury. Cell models are suitable for preliminary mechanistic screening, including oxidative stress, inflammatory signaling, tight junction protein expression, apoptosis, and the protective effects of candidate drugs.
Cell models cannot fully simulate gastric acid secretion, mucosal blood flow, immune infiltration, and tissue repair processes. Therefore, in vitro results should be used as mechanistic clues, while key conclusions still require validation using animal models or histological evidence.
4.2 Ex Vivo Gastric Tissue Models
Ex vivo gastric tissue or gastric mucosal perfusion models can be used to observe the direct effects of drugs on the gastric mucosal barrier, epithelial integrity, and local injury. This model reduces interference from systemic metabolism and neuroendocrine factors, but tissue viability is limited, making it suitable as a supplementary validation tool for pharmacodynamic and mechanistic studies.
Table 4 Application Positioning of In Vivo and In Vitro Models in Gastric Ulcer Research
Model Level | Common Systems | Applicable Questions | Main Limitations |
Animal models | Rats, mice, Mongolian gerbils | Ulcer formation, inflammatory infiltration, tissue repair, pharmacodynamic evaluation | Higher cost; requires ethical approval and control of model consistency |
Gastric epithelial cell models | GES-1, AGS | Oxidative stress, apoptosis, barrier proteins, drug mechanism screening | Lack of gastric acid, blood flow, and immune microenvironment |
Ex vivo gastric tissue models | Ex vivo gastric mucosa or gastric tissue slices | Local mucosal response and direct drug effects | Short observation window and difficulty simulating long-term repair |
5 Evaluation Indicators for Gastric Ulcer Models
5.1 Gross and Histological Evaluation
(1) Ulcer index
The ulcer index is usually calculated based on ulcer area, number, length, or severity of hemorrhagic injury, and is the most intuitive endpoint indicator in gastric ulcer models. In acute models, hemorrhagic bands and erosion area should be evaluated; in chronic models, ulcer area reduction and marginal repair should be emphasized.
(2) Histological evaluation
HE staining can reveal epithelial shedding, mucosal necrosis, inflammatory cell infiltration, and glandular structure disruption. PAS staining can be used to evaluate the gastric mucus layer and glycoprotein protective barrier. In chronic ulcer models, Masson staining can also be used to observe collagen deposition and tissue repair status.
5.2 Biochemical and Molecular Indicators
(1) Gastric acid- and digestive enzyme-related indicators
In pylorus ligation models and acid-related injury studies, gastric juice volume, pH, total acidity, and pepsin activity should be measured. If antacid drugs or gastric acid secretion inhibitors are being evaluated, these indicators have greater mechanistic value than ulcer area alone.
(2) Oxidative stress and inflammatory indicators
MDA, SOD, GSH, GSH-Px, and MPO are commonly used to evaluate oxidative injury, antioxidant defense, and inflammatory infiltration. TNF-α, IL-1β, and IL-6 can be used to analyze gastric mucosal inflammatory responses. Oxidative stress indicators are especially valuable in ethanol, stress, and ischemia-reperfusion models, while inflammatory factors and MPO better reflect the injury process in NSAID- and infection-related models.
(3) Barrier repair and angiogenesis indicators
Occludin, ZO-1, claudins, MUC1, MUC5AC, EGF, VEGF, and TGF-β can be used to evaluate gastric mucosal barrier integrity and repair processes. In chronic ulcer healing studies, these indicators should be interpreted together with histological repair results.
Table 5 Common Evaluation Indicators for Gastric Ulcer Models
Evaluation Level | Common Indicators | Application Value | Applicable Models |
Gross injury | Ulcer area, ulcer index, hemorrhagic bands | Determines modeling success and drug protective effects | Ethanol, NSAIDs, stress, pylorus ligation |
Histology | HE, PAS, Masson | Evaluates necrosis depth, inflammatory infiltration, mucus layer, and repair status | Acute and chronic models |
Gastric acid secretion | Gastric juice volume, pH, total acidity | Evaluates acid-related injury and antacid efficacy | Pylorus ligation model |
Digestive enzymes | Pepsin activity, PGⅠ, PGⅡ | Analyzes the gastric acid-pepsin injury axis and gastric functional status | Pylorus ligation and acid-related injury models |
Oxidative stress | MDA, SOD, GSH, GSH-Px | Determines ROS-mediated injury and antioxidant effects | Ethanol, stress, ischemia-reperfusion |
Inflammatory response | TNF-α, IL-1β, IL-6, MPO | Evaluates inflammatory cell infiltration and cytokine release | NSAIDs, infection, ischemia-reperfusion |
Barrier repair | ZO-1, occludin, MUC5AC, EGF, VEGF | Evaluates mucosal barrier and ulcer healing | Acetic acid chronic ulcer and drug repair studies |
6 Selection of Related Products and Materials
Table 6-1 Products Related to Oxidative Stress Evaluation
Product Category | Cat. No. | Product/Material Name | Grade & Purity | Application Positioning |
Lipid peroxidation detection | Malondialdehyde (MDA) Content Assay Kit (TBA, Colorimetric Method) | BioReagent | Used for detecting lipid peroxidation levels in gastric mucosal tissue; suitable for ethanol, stress, and ischemia-reperfusion models | |
Lipid peroxidation detection | Malondialdehyde (MDA) Content Assay Kit (TBA, Fluorometric Method) | BioReagent | Used for low-content samples or higher-sensitivity MDA detection | |
Lipid oxidation detection | Lipid Peroxidation (MDA) Assay Kit | Sufficient for 100 colorimetric or fluorometric tests | Used for evaluating lipid oxidative injury in gastric mucosa and can serve as a supplementary MDA detection option | |
Animal sample MDA detection | Rat Malondialdehyde(MDA) ELISA Kit | BioReagent | Used for detecting MDA levels in rat gastric ulcer models | |
SOD activity detection | Total Superoxide Dismutase (T-SOD) Activity Assay Kit (WST-8, Micro Method) | BioReagent | Used for detecting SOD activity in gastric mucosal tissue; suitable for small-volume samples and microplate readings | |
SOD activity detection | Total Superoxide Dismutase (SOD) Assay Kit (NBT Riboflavin Microplate Method) | BioReagent | Used for total SOD activity evaluation and oxidative stress mechanism analysis | |
SOD activity detection | Total Superoxide Dismutase (SOD) Activity Assay Kit (Pyrogallol, UV Colorimetric Method) | BioReagent | Used for detecting SOD activity by UV colorimetry | |
Animal sample SOD detection | Rat Superoxide Dismutases (SOD) ELISA Kit | BioReagent | Used for detecting SOD levels in rat samples | |
Animal sample SOD detection | Mouse Superoxide Dismutases (SOD) ELISA Kit | BioReagent | Used for detecting SOD levels in mouse gastric injury models | |
Glutathione detection | Total Glutathione (T-GSH) Content Assay Kit (DTNB, Micro Method) | BioReagent | Used for evaluating glutathione antioxidant reserves in gastric mucosa | |
Glutathione detection | Reduced Glutathione (GSH) Content Assay Kit (DTNB, Micro Method) | BioReagent | Used for detecting reduced GSH levels and evaluating redox status | |
GSH-Px activity detection | Glutathione Peroxidase (GSH-Px) Activity Assay Kit (DTNB, Micro Method) | BioReagent | Used for evaluating antioxidant enzyme system activity in gastric mucosa |
Table 6-2 Products Related to Inflammatory Response Evaluation
Product Category | Cat. No. | Product/Material Name | Grade & Purity | Application Positioning |
Neutrophil infiltration detection | Myeloperoxidase (MPO) Activity Assay Kit (o-Dianisidine, Micro Method) | BioReagent | Used for evaluating neutrophil infiltration and inflammatory injury in gastric mucosa | |
Animal sample MPO detection | Rat Myeloperoxidase (MPO) ELISA Kit | BioReagent | Used for detecting MPO levels in rat gastric ulcer models | |
Animal sample MPO detection | Mouse Myeloperoxidase (MPO) ELISA Kit | BioReagent | Used for evaluating inflammatory injury in mouse gastric mucosa | |
Inflammatory factor detection | Rat Tumor Necrosis Factor Alpha (TNF-α) ELISA Kit | BioReagent | Used for detecting TNF-α levels in rat gastric ulcer models | |
Inflammatory factor detection | Mouse Tumor Necrosis Factor Alpha (TNF-α) ELISA Kit | BioReagent | Used for evaluating TNF-α-mediated inflammatory responses in mouse models | |
Inflammatory factor detection | Rat Interleukin 1 Beta (IL-1β) ELISA Kit | BioReagent | Used for detecting inflammatory factors in rat gastric mucosa | |
Inflammatory factor detection | Mouse Interleukin 1 Beta (IL-1β) ELISA Kit | BioReagent | Used for detecting IL-1β levels in mouse gastric injury models | |
Inflammatory factor detection | Rat Interleukin 6 (IL-6) ELISA Kit | BioReagent | Used for evaluating inflammatory responses in rat gastric ulcers | |
Inflammatory factor detection | Mouse Interleukin 6 (IL-6) ELISA Kit | BioReagent | Used for detecting IL-6 in mouse gastric mucosal inflammation models | |
Human cell model detection | Human Tumor Necrosis Factor Alpha (TNF-α) ELISA Kit | BioReagent | Used for detecting inflammatory factors in human cell models such as GES-1 and AGS | |
Human cell model detection | Human Interleukin 1 Beta (IL-1β) ELISA Kit | BioReagent | Used for analyzing inflammatory responses in human gastric epithelial cells | |
Human cell model detection | Human Interleukin 6 (IL-6) ELISA Kit | BioReagent | Used for detecting IL-6 release in human cell injury models |
Table 6-3 Products Related to Gastric Acid, Pepsin, and Ulcer Repair
Product Category | Cat. No. | Product/Material Name | Grade & Purity | Application Positioning |
Pepsin activity detection | Pepsin Activity Assay Kit (Micro Method) | BioReagent | Used for detecting pepsin activity in pylorus ligation models | |
Pepsin activity detection | Pepsin Activity Assay Kit (Colorimetric Method) | BioReagent | Used for evaluating the acid-pepsin injury axis | |
Gastric function-related detection | Rat Pepsinogen Ⅰ(PGⅠ) ELISA Kit | BioReagent | Used for evaluating gastric mucosal injury and gastric functional status in rats | |
Gastric function-related detection | Rat Pepsinogen Ⅱ(PGⅡ) ELISA Kit | BioReagent | Used for detecting PGⅡ levels in rat models | |
Gastric function-related detection | Mouse Pepsinogen Ⅰ(PGⅠ) ELISA Kit | BioReagent | Used for detecting PGⅠ levels in mouse gastric injury models | |
Gastric function-related detection | Mouse Pepsinogen Ⅱ(PGⅡ) ELISA Kit | BioReagent | Used for detecting PGⅡ levels in mouse models | |
Human cell/sample detection | Human Pepsin (Pepsin) ELISA Kit | BioReagent | Used for pepsin-related detection in human samples or in vitro models | |
Epithelial repair detection | Rat Epidermal Growth Factor (EGF) ELISA Kit | BioReagent | Used for analyzing chronic ulcer healing and epithelial repair mechanisms in rats | |
Epithelial repair detection | Mouse Epidermal Growth Factor (EGF) ELISA Kit | BioReagent | Used for detecting EGF levels in mouse ulcer repair models | |
Human cell/sample detection | Human Epidermal Growth Factor (EGF) ELISA Kit | BioReagent | Used for detecting EGF in human gastric epithelial cells or related samples | |
Angiogenesis detection | Rat Vascular Endothelial Growth Factor (VEGF) ELISA Kit | BioReagent | Used for evaluating angiogenesis and chronic ulcer healing in rats | |
Angiogenesis detection | Mouse Vascular Endothelial Growth Factor (VEGF) ELISA Kit | BioReagent | Used for detecting VEGF-mediated repair responses in mouse models | |
Human cell/sample detection | Human Vascular Endothelial Growth Factor (VEGF) ELISA Kit | BioReagent | Used for detecting VEGF levels in human cells or clinically related samples |
7 Frequently Asked Questions
7.1 How should models be selected for acute gastric mucosal protection studies?
Ethanol- or NSAID-induced models should be prioritized for acute gastric mucosal protection studies. The ethanol model is more suitable for evaluating mucosal barrier protection, antioxidant effects, and anti-inflammatory activity. NSAID models are more suitable for studying decreased prostaglandins, weakened mucus barrier, and drug-related gastric injury. If a candidate drug is positioned as an antacid, the pylorus ligation model is more mechanistically matched.
7.2 How should endpoints be set in the acetic acid-induced chronic ulcer model?
The acetic acid model should not be evaluated only by final ulcer area. Multiple healing time points are recommended, combined with ulcer area measurement, HE staining, Masson staining, EGF, VEGF, and tight junction protein detection to evaluate re-epithelialization, angiogenesis, and tissue remodeling quality.
7.3 How should gastric acid indicators and ulcer index be jointly interpreted in the pylorus ligation model?
In the pylorus ligation model, gastric juice volume, pH, total acidity, and pepsin activity should be measured together. If a drug reduces the ulcer index while also decreasing total acidity or pepsin activity, this supports a relationship with inhibition of acid secretion. If ulcer improvement occurs without obvious changes in acidity, mucosal protection, antioxidant effects, or anti-inflammatory mechanisms should be further analyzed.
7.4 How can intra-group variation be controlled in stress ulcer models?
Stress models are highly sensitive to environmental and operational conditions. Water temperature, ambient temperature, restraint intensity, stress duration, animal body weight, and fasting status should all be standardized. Preliminary experiments are recommended before formal studies to determine conditions that produce stable injury without excessively high mortality.
7.5 How should successful establishment of a Helicobacter pylori infection model be determined?
A successful infection model should not be judged only by completion of inoculation. Gastric tissue bacterial colonization detection, rapid urease testing, histological inflammation scoring, and inflammatory factor levels should be combined. If the model is used for drug intervention studies, antibacterial effects, anti-inflammatory effects, and mucosal repair effects should also be distinguished.
Animal models of gastric ulcer should be selected according to acute injury, chronic repair, acid secretion, stress response, or infection mechanisms. Integrated analysis of ulcer index, histology, biochemical indicators, and molecular markers can improve the interpretability of model results and the reliability of pharmacodynamic evaluation.
For more related articles, please see below:
[1] The Technology Driving Biomedical Revolution — Animal Modeling
[2] Animal Modeling—Tumor Disease Models
[3] A Detailed Guide to the Construction of Animal Models for Metabolic Diseases
[4] Methods for Establishing Animal Models of Cardiovascular Diseases
[5] Methods for Establishing Models of Nervous System Diseases
