Effect of pentoxifylline on vascular endothelial growth factor C and flk-1 expression on endometrial implants in the rat endometriosis model

Objective: To investigate the effects of pentoxifylline, on vascular endothelial growth factor (VEGF)-C and flk-1 expression in the rat endometriosis model. Design: Prospective, randomized, placebo-controlled study. Setting: Academic institution. Animal(s): Twenty Wistar rats with surgically induced endometriosis. Intervention(s): Animals were evaluated after surgical induction of endometriosis and random allocation to a group that received pentoxifylline and a control group that received NaCl 0.9%, for 3 weeks. At the end of the treatment period the animals were killed and the implants evaluated macroscopically as well as by immunohistochemistry. Main Outcome Measure(s): Morphologic changes of the endometriotic implants; and evaluation of VEGF-C and flk-1 expression by a semiquantitative analysis (HSCORE) for the intensity of immunohistochemical reactivity. Result(s): A significant reduction was observed in the mean volume of the endometriotic implants per animal in the treatment group as compared with the control group. There was a significant reduction not only in the mean volume of implants per animal but also in the mean number of implants per animal after treatment. By immunohistochemical evaluation (HSCORE), there was a significant reduction in VEGF-C expression after treatment in all areas examined. A significant reduction of flk-1 expression was also noted in the glandular compartment after treatment but not in the epithelial surface or stroma. Conclusion(s): Pentoxifylline may cause suppression of endometriotic lesions by suppressing angiogenesis through VEGF-C and flk-1 expression.