Evaluation of the cutaneous anti-inflammatory activity of azaspiranes.

OBJECTIVE AND

DESIGN

The ability of azaspiranes to modulate the acute inflammatory response in models of skin inflammation was examined.

MATERIAL: The in vivo experiments involved the use of 5-6 age-matched male Balb/c inbred mice (22-25 g) per treatment group and a control group of 8-10 animals. In vitro mechanistic studies used RBL-1 and U937 cells lines and freshly isolated human monocytes.

TREATMENT: Arachidonic acid (AA) (2 mg/20 microl in acetone) or PMA (phorbol myristate acetate) (4 microg/20 microl) were applied topically. SK&F 106615 and SK&F 106610 were administered topically either dissolved in acetone or dimethylacetamide just after the application of the irritant. Isolated cells were treated with the compounds dissolved in DMSO.

METHODS

The thickness and influx of neutrophils into the treated ears was measured as was the effects of the azaspiranes on 5-lipoxygenase activity, cyclooxygenase activity, prostaglandin and leukotriene synthesis, and the activation of the transcription factor NF-kappaB.

RESULTS

SK&F 106615 and SK&F 106610 significantly reduced inflammation in the AA- and PMA-induced inflammation models (p < 0.05) with ED50's of 179 and 120 mg/ear for edema and myeloperoxidase, respectively. The compounds did not inhibit eicosanoid biosynthesis, have a direct effect on 5-lipoxygenase or cyclooxygenase enzymes, or inhibit NF-kappaB.

CONCLUSIONS

The potent anti-inflammatory and immunomodulatory activities of the azaspiranes observed in these and other studies appear to be mediated by a novel mechanism.