Expression of neurotrophic tyrosine kinase receptor TrkB in eutopic and ectopic endometium of women with endometriosis

Objective To investigate the expression of neurotrophic tyresine kinase receptor TrkB in the eutopic and ectopic endometium of women with endometriosis and evaluate the role of TrkB in the pathogenesis of endometriosis. Methods Seventeen women with endometriosis and 9 controls were studied. Expression of TrkB was investigated using RT-PCR, immunohistochemistry and Western blot, respectively. Results TrkB mRNA was expressed in eutopic endometrium in secretory phase and ectopic endometium of women with endometriosis, (23.51±0.51)% vs (35.29±0.67) % (P<0.05), but TrkB mRNA expression was not detected in control endometrium and eutopic endometrium in proliferative stage of women with endometriosis by RT-PCR. TrkB was expressed both on membrane (glycosylated receptor) and in cytoplasm (non-glycosylated receptor) of the glandular epithelial cells of ectopic endometium, and more often observed in cytoplasm of glandular epithelial cells of eutopic endometrium in secretory phase of women with endometriosis by IHC. In eutopic endometrium in secretory phase and ectopic endometium of women with endometriosis, the expression of TrkB protein was (0.12±0.02)% vs (0.37±0.01)% (P<0.05) by Western blot. Conclusions There is an overexpression of TrkB in eutopic endometrium in secretory phase and ectopic endometium of women with endometriosis. Full-length (glycosylated receptor) TrkB more often is overexpressed in ectopic endometium of women with endometriosis, and TrkB may act as a pathogenic role in formation of endometriosis. Key words: Endometriosis;  Eutopic endometium;  Ectopic endometium