Development of equine models of inflammation. The Ciba-Geigy Prize for Research in Animal Health.

The research presents two incredibly controlled models for studying acute non-immune inflammation in equines. The conducted studies allowed for a more accurate evaluation of the composition and cellular content of exudates during an inflammatory reaction.

Experimental Models of Acute Non-Immune Inflammation

• The research introduces two experimental models for studying acute non-immune inflammation. Both models are designed to create a consistent, reversible, and moderate inflammatory reaction while minimizing distress to the experimental animals and eliminating uncontrollable external factors. The two models are the ‘polyester sponge model’ and the ’tissue-cage model’.

Polyester Sponge Model

• For the polyester sponge model, small strips of polyester sponge are soaked in sterile carrageenan solution and inserted into subcutaneous pouches in the neck. These are then routinely removed to track the progression and nature of the inflammatory response.
• In study results, polymorphonuclear (PMN) leukocyte counts progressively increased in this model presenting a more nuanced understanding of white blood cell behavior during inflammation.

Tissue-Cage Model

• The tissue-cage model involves subcutaneously placing a spherical tissue-cage in the neck. The lining and granulation tissue within the cage are stimulated with carrageenan, inducing an inflammatory reaction.
• Cell numbers in this model were seen to be at their peak at the 12-hour mark.

Study Observations

• The acute inflammatory exudates generated in the reactions were discovered to contain eicosanoids, with the primary type being Prostaglandin E2, a bioactive lipid compound involved in alteration of vasomotor tone and platelet function.
• The research also explores the relationships between eicosanoid formation (at the site of inflammation), white blood cell accumulation, enzyme release, total protein content of exudates, and temperature of the lesions, facilitating a holistic examination of inflammation progression.