Expression of microtubule associate protein 2 and synaptophysin in endometrium: high levels in deep infiltrating endometriosis lesions

Objective To assess whether healthy endometrium, eutopic endometrium, and endometriotic lesions express nerve growth factor (NGF), microtubule-associated protein 2 (MAP-2), and synaptophysin (SYP). Design Molecular study in tissue extracts. Setting University hospital. Patient(s) A group of women (n = 70), divided as [1] healthy controls (n = 30) and [2] with endometriosis (n = 40), was included. Intervention(s) From the healthy control group an endometrial specimen was collected by hysteroscopy (proliferative phase, n = 16; secretive phase, n = 14). Endometriotic and endometrial specimens were collected from women undergoing laparoscopic surgery for endometriosis, endometrioma (OMA) (n = 20), or deep infiltrating endometriosis (DIE) (n = 20). Main Outcome Measure(s) To assess expression of NGF, MAP-2, and SYP messenger RNA (mRNA) levels in endometrium and in endometriosis by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and protein localization by immunofluorescence. Cultures of human endometrial stromal cells were used to evaluate the effect of tumor necrosis factor (TNF)-α on NGF and SYP. Result(s) Endometrial tissue from control expressed mRNA for NGF, MAP-2, and SYP, without any difference between proliferative and secretive phase. The DIE and OMA lesions showed the highest NGF mRNA expression, significantly higher than in eutopic endometrium and control. In DIE lesions SYP mRNA expression was higher than in OMA or in eutopic endometrium or controls. Immunofluorescence analysis of NGF, MAP-2, and SYP showed a slightly more intense positive signal in endometriotic lesions. Exposure to TNF-α increased NGF and SYP mRNA expression in endometrial culture cells. Conclusion(s) The present study revealed the presence of two selected neuronal markers, MAP-2 and SYP mRNAs and protein expression, in eutopic endometrium and in endometriotic lesions.