The effect of locally injected anti-inflammatory drugs on the carrageenin granuloma in rats

Abstract

Granuloma was induced by injecting 2% carrageenin solution s.c. on the dorsum of rats. The granuloma pouch reached a peak in wet weight at day 5, then production of collagen in the pouch was accelerated, while accumulation of the pouch fluid took place mainly during 5–9 days. The total weight of granuloma pouch and its fluid amounted to about 20 per cent of total body weight. The effect of anti-inflammatory drugs on the carrageenin granuloma was investigated in two ways. In the first experiment, drugs were tested for the inhibitory action on the granuloma formation by means of daily subcutaneous injections for 5 days beginning on the day of carrageenin injection. The second experiment was to test the ability of the drugs to reduce the preformed granuloma, in which drugs were daily applied directly into the pouch wall and its collagen content was determined. Drugs employed were betamethasone as a steroidal drug, indomethacin, phenyl-butazone and salicyclic acid as non-steroidals. A steroidal drug revealed an ability both to inhbit the formation of granuloma and to reduce the pre-existing granuloma, while non-steroidal drugs failed to reduce the pre-existing granuloma, though they had some effects on the granuloma formation. Some differences were noted in the mode of action among these non-steroidal drugs. Diet limitation which resulted in marked body weight loss in young rats had little influence on both the formation and the maintenance of the carrageenin granuloma.