Comparative effect of danazol and a GnRH agonist on monocyte chemotactic protein-1 expression by endometriotic cells

Endometriosis is associated with a chronic inflammatory process, and the increased number of activated peritoneal macrophages is one of the major hallmarks of this process. The medical treatment of the disease, which is based on the creation of an hypoestrogenic milieu unfavorable to the growth of endometriotic lesions, is often associated with a reduced peritoneal inflammation. The aim of this study was to investigate the ability of current therapeutic agents to modulate, through a direct mechanism, the expression by endometriotic cells of monocyte chemotactic protein-1 (MCP-1), a chemokine endowed with the potent faculty of recruiting and activating macrophages.

Cells were stimulated with interleukin-1 beta (IL-1beta) to induce MCP-1 expression. MCP-1 protein secretion and mRNA steady-state levels were evaluated by ELISA and northern blot, respectively.

Our results show that danazol concentrations (10(-7) -10(-5) M), taking into account the therapeutic levels found in the plasma of treated patients, inhibited MCP-1 protein and mRNA steady-state levels in endometriotic cells, whereas buserelin acetate (0.1-10 ng/mL), a GnRH agonist, had no significant effect. Dexamethasone, an anti-inflammatory glucocorticoid, used at concentrations varying between 10(-12) and 10(-6) M, also displayed a dose-dependent inhibitory action.

These results put into prominence the capability of danazol to directly inhibit the expression of a potent monocyte chemotactic and activating factor by ectopic endometrial cells shedding more light on the mechanisms underlying the clinical effects of hormonal therapeutic agents used in the treatment of endometriosis.