Objective: To evaluate changes in expression levels of vascular endothelial growth factor (VEGF) mRNA in human endometrial explants in a chicken chorioallantoic membrane model of endometriosis.
Design: Experimental prospective study.
Setting: University hospital.
Patient(s): Endometrial biopsy samples were obtained from healthy, ovulating women undergoing elective surgery.
Intervention(s): Endometrial fragments were placed on the chicken chorioallantoic membrane and removed for analysis after 0, 24, 48, and 72 hours.
Main outcome measure(s): Expression of different VEGF mRNA splice variants was tested. Expression of VEGF(165) mRNA was assessed by using competitive polymerase chain reaction and normalized to expression of the housekeeping gene human glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA.
Result(s): After 0, 24, 48, and 72 hours of incubation, all grafts expressed VEGF(121), VEGF(145), VEGF(165), and VEGF(189) mRNA. Expression of VEGF(165) mRNA increased up to 10-fold at 24 to 72 hours compared with precultivation values.
Conclusion(s): Levels of VEGF(165) mRNA in endometrial grafts increase after implantation on chicken chorioallantoic membrane. Hypoxic induction of VEGF mRNA expression in endometrial cell cultures has been reported previously. Induction of VEGF expression might indicate relative hypoxia of the specimen due to insufficient vascularization. Expression of VEGF may assist in vascularization of endometrial explants after retrograde menstruation.