EFFECTS OF LIPOSTEROID ON SKIN-LESIONS IN AUTOIMMUNE MRLLPR LPR MICE/

Dexamethasone palmitate (D-PAL) incorporated into lipid microspheres ( D-PAL emulsion) is taken up by the reticuloendothelial system and by s ome inflammatory cells. Therefore, it has a stronger anti-inflammatory activity than free corticosteroids in vivo. To study the effect of D- PAL emulsion on systemic lupus erythematosus (SLE), we administered D- PAL emulsion to MRLlpr/lpr mice, an animal model for human SLE. The ef fect of D-PAL emulsion was compared with that of methylprednisolone (m -PSL), a water-soluble steroid. Percent survival was higher in the gro up treated with 0.25 mg of D-PAL emulsion intravenously once every 4 w eeks than in those groups treated similarly with m-PSL or PBS control. Swelling of lymph nodes was frequent in the group treated with m-PSL or with PBS, while rarely observed in the group treated with D-PAL emu lsion. Proteinuria was more frequent in the groups treated with m-PSL or PBS than in the group treated with D-PAL emulsion. Although the fre quency of skin lesions was not different between these three groups, t he control and m-PSL treated mice had severe skin lesions, such as hai r loss of erythematous skin with scales and crusts at the nape, while D-PAL emulsion treated animals showed only facial alopecia without inf lammatory skin changes. These data demonstrate that D-PAL emulsion was more effective than a corresponding dose of m-PSL on autoimmune prone mice. This suggests that intermittent administration of D-PAL emulsio n may be effective in the treatment of human SLE. (C) 1997 Elsevier Sc ience Ireland Ltd.