Immunohistochemical study of osteopontin and L-selectin in a rat endometriosis model and in human endometriosis

OBJECTIVE: To investigate the localization of the proteins osteopontin (OPN) and L-selectin (SELL). DESIGN: Retrospective nonrandomized immunohistochemical study in a surgically induced rat model of peritoneal endometriosis and in samples of human endometriotic lesions of ovaries. SETTING: Department of gynecology in a university hospital. PATIENT(S): A rat endometriosis model was induced in 10 8-week-old SLC-Sprague-Dawley rats by surgical autotransplantation of uterus. Fourteen premenopausal women with histologically diagnosed endometriosis were selected (mean age, 39 y; range, 25-53 y). Twenty endometriotic specimens were obtained from 14 patients who underwent laparoscopic surgery for enlarged endometriotic cysts. INTERVENTION(S): Histopathological examination of endometriotic ovarian specimens for OPN and SELL expression by immunohistochemistry. MAIN OUTCOME MEASURE(S): Demonstration of the immunoreactive staining of OPN and SELL expressions in tissues of a rat endometriosis model and of human endometriosis. RESULT(S): In both tissues from a rat endometriosis model and from human endometriosis, OPN was stained more prominently in glandular epithelium than in interstitial space, whereas SELL stained more prominently in interstitial space (macrophages and lymphocytes) than in epithelium. The staining pattern of OPN in ectopic endometriotic lesions was very similar to that in eutopic normal human endometrium in the secretory phase. CONCLUSION(S): These results suggested important roles for OPN and SELL in the pathogenesis of endometriosis.