Air Pouch Model (APM)

An air pouch is produced by the subcutaneous injection of sterile air into the back of a rat or mouse. The pouch generated mimics the synovial cavity providing a localized environment in which to study cell trafficking and the inflammatory response. Injection of an inflammatory irritant (LPS/Carrageenan) into the air pouch produces an inflammatory response that is characterized by the infiltration of inflammatory cells and the production of cytokines/chemokines. In addition to it’s usefulness as a model to study the anti-inflammatory activity of test compounds in efficacy studies, the Air Pouch Model may also provide insight into the actual mechanism of a compound’s action. Through differential cell analysis of inflammatory exudates, a drug’s ability to suppress specific inflammatory cell types these can be investigated helping to elucidate its function.

Category(s)

Preclinical Drug Efficacy Studies

Species

Murine (Mice or Rats)

Basic Methodology

An air pouch is generated by the injection of sterile air under the skin on the back of the animal. The animal is then administered either a known anti-inflammatory compound or a novel test article of interest. Following treatment with a compound, the animals are treated with LPS or with another inflammatory irritant. After study completion, the air pouch is lavaged and the fluid is collected. The lavage fluid is analyzed for inflammatory cell recruitment and cytokine release. In addition, cytokines within blood serum may be analyzed.

Measurements

General clinical observations, body weight, cytokine profiling in blood and lavage fluid using ELISA and Luminex multiplex assays, flow cytometric analysis of lavage fluid for inflammatory cell characterization

Reference Substance(s):

Dexamethasone (or other anti-inflammatory compound)

Literature References:

Sin YM, Sedgwick EP, Willoughby DA. (1986) Mast cells in newly formed lining tissue during acute inflammation: a six day air pouch model in the mouse. Annals of the Rheumatic Diseases; 45:873-877.