Abstract

For the appraisal of acute inflammation, the authors describe a quantitative method that employs the normal dog and offers a means of comparing the relative potencies of anti-inflammatory drugs. The investigator injects an inflammatory agent into one of the dog's knee joints and then measures the pressure exerted by the appropriate paw when the dog stands without restraint. In the study presented, the authors used this method to compare the inflammatory effects of carrageenan, sodium urate, ellagic acid and cellulose sulfate. For parallel appraisal of those effects in the rat, the authors used another method, measurement of paw swelling. Cellulose sulfate appeared to have a mechanism different from the other agents and was dropped from further investigation. The authors then recorded, for both rats and dogs injected with the first three agents mentioned above, dose-response curves for five anti-inflammatory drugs, among them aspirin and indomethacin. The results indicate that the mechanisms of the infiammations induced by three of the agents are similar in a given species and similar or even identical from one species in one mammalian order to another species in a different mammalian order and that the anti-inflammatory drugs tested apparently had, despite different chemical structures, a common mode of action. It is proposed that acidic nonsteroid anti-inflammatory agents, and possibly other types also, are effective because they prevent the neutrophil from performing its normal release of certain enzymes after the neutrophil has arrived at the site of inflammation.