Identification of p75 and TrkB receptors role in the incidence of endometriosis and endometrioma tissue invasion onto chorioallantoic membrane

Background: The tropomyosin kinase receptor B (TrkB) and p75 receptors may play a role in the formation of deep endometriosis and are related to the more intense pain in deep nodular endometriosis. Neurotrophins brain-derived neurotrophic factor (BDNF) regulate the survival, growth, and programmed cell death of neurons. This study aimed to explore the expression of BDNF and its receptors in endometriosis and endometrioma tissue invasion implanted in the chorioallantoic membrane (CAM) of chicken eggs. Methods: Peritoneal endometriosis lesion, endometrioma, and eutopic endometrium were taken from 27 women who underwent hysteroscopy/laparoscopy and analyzed with 15 tissue samples in each group. The age of the patients ranged from 22-45 years old. Samples were transplanted into CAM of fertile chicken eggs for five days then harvested, and histological preparations were made using the paraffin method. IHC staining was performed on p75, Ki67, TrkB, and BDNF stains. Invasion analysis and IHC evaluation was performed with a semi quantitative method. Data were analyzed using SPSS Statistics version 25.0. Result: Normal endometrium expressed the highest expression of BDNF than peritoneal endometriosis and endometrioma. The endometrioma expressed the highest expression of TrkB than other tissues. The P75 expression correlated positively with Ki67 expression in peritoneum and endometrioma samples (p = 0.012; p = 0.008). Conclusion: The p75 receptor may have a role in endometriosis tissue proliferation, but this receptor does not play a direct role in the process of tissue invasion into CAM. While proliferation in endometriomas is positively correlated with invasion into CAM, it is not correlated with peritoneal endometriosis.