Regression of endometrial explants in a rat model of endometriosis treated with the immune modulators loxoribine and levamisole

Objective: To investigate the effects of the immune modulators levamisole and loxoribine in a rat model of endometriosis. Design: Prospective, placebo-controlled study. Setting: Hospital-based research facility. Animal(s): Nineteen rats with experimentally induced endometriosis. Intervention(s): Rats were treated with three weekly intraperitoneal injections of levamisole (2 mg per rat; n = 6), loxoribine (1 mg per rat; n = 6), or saline (control; n = 7) and killed 8 weeks after treatment. Main Outcome Measure(s): Histologic and immunohistochemical analysis of endometriotic explants. Result(s): The loxoribine-treated group showed marked regression of both epithelial and stromal components. Epithelial regression was noted in the control group, but the epithelium was strikingly preserved in the levamisole group. There were significantly greater numbers of dendritic cells in the explants of animals treated with loxoribine and levamisole. The number of natural killer cells was significantly reduced in loxoribine-treated explants. Conclusion(s): Loxoribine, a potent immunomadulatory drug, appeared to cause regression in both stromal and epithelium components in a rat model of endometriosis. Further, specific cell-mediated immune responses in this model of endometriosis were elucidated. (Fertil Steril(R) 1999;72:135-41. (C) 1999 by American Society for Reproductive Medicine.)