Methods to Measure Gastric Mucosal Lesions in the Rat

Giuseppina Morini1, Daniela Grandi1

1 Department of Human Anatomy, Pharmacology, and Forensic Medicine, University of Parma, Parma, Italy
Publication Name:  Current Protocols in Toxicology
Unit Number:  Unit 21.2
DOI:  10.1002/0471140856.tx2102s43
Online Posting Date:  February, 2010
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Abstract

The maintenance of gastric mucosal integrity is ensured by a dynamic balance between protective and noxious factors. The gastric mucosa has multiple protective mechanisms that allow the mucosa to withstand frequent exposure to potentially damaging agents such as acid and peptic secretions, bacterial products, ingested food, alcoholic beverages, and certain drugs. The imbalance between defensive and aggressive factors is at the basis of the formation of erosions/lesions or ulcerations of the gastric mucosa. The difference between an erosion/lesion and ulceration is that the former is confined to the mucosa, while an ulceration penetrates to the muscularis mucosae. This unit presents two models of acute mucosal lesions induced in the rat by gastrotoxic agents acting through different mechanisms of action. The protocols explain how to measure gastric mucosal lesions by microscopic examination of the stomach by light microscopy and by scanning electron microscopy. Curr. Protoc. Toxicol. 43:21.2.1‐21.2.15. © 2010 by John Wiley & Sons, Inc.

Keywords: rat; gastric mucosal lesions; macroscopic evaluation; light microscopy; scanning electron microscopy

     
 
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Table of Contents

  • Introduction
  • Basic Protocol 1: Assessing Acute Gastric Lesions Induced by Necrotizing Agents
  • Basic Protocol 2: Macroscopic Evaluation of Gastric Damage
  • Alternate Protocol 1: Evaluation of Gastric Damage by Light Microscopy
  • Alternate Protocol 2: Evaluation of Gastric Damage by Scanning Electron Microscopy
  • Basic Protocol 3: Evaluating Acute Gastric Lesions Induced by Conventional NSAIDs
  • Reagents and Solutions
  • Commentary
  • Literature Cited
  • Figures
     
 
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Materials

Basic Protocol 1: Assessing Acute Gastric Lesions Induced by Necrotizing Agents

  Materials
  • Adult rats (male, body weight of 200 to 220 g, 9 to 10 weeks old)
  • Necrotizing agent:
    • Absolute ethanol
    • 0.6 N HCl ( appendix 2A)
    • 0.2 N NaOH ( appendix 2A)
    • 25% (w/v) NaCl ( appendix 2A)
  • Rat housing
  • Animal balance
  • Orogastric tube
  • Surgical tools

Basic Protocol 2: Macroscopic Evaluation of Gastric Damage

  Materials
  • Treated adult male rats with open abdomens (see protocol 1)
  • 0.9% (w/v) NaCl ( appendix 2A)
  • Dissecting board and pins
  • Stereomicroscope
  • Transparent plastic 1‐mm grids

Alternate Protocol 1: Evaluation of Gastric Damage by Light Microscopy

  Materials
  • Treated adult male rats with open abdomens (see protocol 1)
  • 10% (v/v) neutral buffered formalin (see recipe)
  • Paraffin wax (melting point 56° to 60°C)
  • Xylene
  • 80%, 96%, and 100% (v/v) ethanol
  • Mayer's hematoxylin (see recipe)
  • Eosin (see recipe)
  • Canada balsam
  • 2‐ml syringe
  • 100‐ml polypropylene jars
  • Biopsy pads
  • Micromesh biopsy processing/embedding cassettes
  • Automatic tissue processor (Sakura Finetechnical)
  • Tissue embedding center (Sakura Finetechnical)
  • Base molds
  • Cold plate
  • Microtome
  • Disposable stainless blades
  • Blunt forceps
  • 45°C distilled water bath
  • 37°C slide warmer
  • Slide holder
  • Staining dish
  • Coverslips
  • Video camera attached to a light microscope (e.g., Nikon Optiphot)
  • Color image analysis software system (e.g., LUCIA G, Nikon Laboratory Imaging)

Alternate Protocol 2: Evaluation of Gastric Damage by Scanning Electron Microscopy

  Materials
  • Treated adult male rat with opened abdomen (see protocol 1)
  • 10% (v/v) neutral buffered formalin (see recipe)
  • 25%, 50%, 75%, 90%, and 100% acetone
  • Critical point dryer (Leica Microsystems)
  • Aluminum stubs (Electron Microscopy Sciences)
  • Double‐sided adhesive tape
  • Sputter coater (Leica Microsystems)
  • Scanning electron microscope

Basic Protocol 3: Evaluating Acute Gastric Lesions Induced by Conventional NSAIDs

  Materials
  • 1% (w/v) carboxymethylcellulose
  • 0.6 N HCl ( appendix 2A)
  • Aspirin (Sigma)
  • Adult rats (male, body weight 200 to 220 g, 9 to 10 weeks old)
  • Indomethacin (Sigma)
  • Orogastric tube
  • Light microscope
  • Scanning electron microscope
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Figures

Videos

Literature Cited

Literature Cited
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   Jones, M.K., Tomikawa, M., Mohajer, B., and Tarnawski, A.S. 1999. Gastrointestinal mucosal regeneration: Role of growth factors. Front. Biosci. 4:D303‐D309.
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   Zhao, C.M., Chen, D., Yamada, H., Dornonville de la Cour, C., Lindstrom, E., Persson, L., and Hakanson, R. 2003. Rat stomach ECL cells: Mode of activation of histidine decarboxylase. Regul. Pept. 114:21‐27.
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