Models of inflammation: carrageenan air pouch

Abstract

The subcutaneous air pouch is an in vivo model that can be used to study acute and chronic inflammation, the resolution of the inflammatory response, and the oxidative stress response. Injection of irritants into an air pouch in rats or mice induces an inflammatory response that can be quantified by the volume of exudate produced, the infiltration of cells, and the release of inflammatory mediators. The model presented in this unit has been extensively used to identify potential anti-inflammatory drugs.

Figure 5.6.1

Analysis of cellular infiltrate in rat air pouch exudates after carrageenan stimulation. Data for each time point represent (A) mean number of cells and (B) percent of total cells for each of four cell types in a group of eight rats for each time point. Data at 0 hr are for untreated animals.

Figure 5.6.2

Amounts of tumor necrosis factor α (TNF-α) and prostaglandin E₂ (PGE₂) present in rat air pouch exudates 3 hr after carrageenan stimulation. Symbols: filled diamond, ng/ml TNF-α or PGE₂ detected for each rat in the experimental group; horizontal line, median level of production for the experimental group. Exudates from unstimulated air pouches contained no detectable levels of TNF-α or PGE₂. Note the extent of variation among the individuals in both groups.