Overexpression of nerve growth factor in peritoneal fluid from women with endometriosis may promote neurite outgrowth in endometriotic lesions

To investigate the role of the nerve growth factor (NGF) in the endometriosis-associated innervation in the development of endometriosis-associated symptoms, 41 peritoneal fluid samples (PF) from patients with surgically and histologically proven endometriosis and 20 PF from patients with other gynecologic conditions were analyzed with Western blot and a novel in vitro model using dorsal root ganglia (DRG) to show neuronal outgrowth; endometrial cells also were analyzed. The results suggest that the PF of endometriosis patients and endometriotic lesions have neurotropic properties, because the Western blot analysis and the cell culture stainings showed NGF expression, and the neurite outgrowth of DRG treated with PF of patients with endometriosis was significantly higher than when treated with PF of patients without endometriosis. Furthermore, blocking NGF with both anti-NGF and K252a leads to a significant decrease in neurite outgrowth.