Interleukin-1β inhibits paw oedema induced by local administration of latex of Calotropis procera extracts

Interleukin-1β (IL-1β), a pro-inflammatory cytokine, has been reported to exhibit anti-inflammatory properties in the carrageenan-induced paw oedema model. In the present study, we have evaluated the anti-inflammatory activity of IL-1β against inflammation induced by local administration of the methanol extract of dried latex of Calotropis procera (MeDL) and compared it with that against carrageenan. The anti-inflammatory activity of standard anti-inflammatory drugs, phenylbutazone (PBZ) and dexamethasone (DEX), was also evaluated against both inflammagens. Injection of an aqueous solution of dried latex and MeDL into the sub-plantar surface of the rat paw produced intense inflammation with a peak response occurring within 2 h, while the peak inflammatory response with carrageenan was obtained at 3 h. Subcutaneous injection of IL-1β was found to be more effective against the inflammatory response elicited by carrageenan (70% inhibition) as compared to MeDL (50% inhibition) at 20μg/kg dose. On the other hand, PBZ effectively inhibited the inflammatory response elicited by both MeDL and carrageenan, while DEX was more effective against carrageenan. Thus, our study indicates that the difference in the anti-inflammatory effect of IL-1β against latex of C. procera extract and carrageenan is due to the release of different mediators released by these inflammagens.