| Endometriosis is a benign estrogen-dependent inflammatory disease, characterized by the presence of endometrial-like tissue outside the uterine cavity. The main symptoms of endometriosis are dysmenorrhea, chronic pelvic pain, dyspareunia, dyschezia, dysuria, and infertility. It seems that the expression of painmediating substances, such as prostaglandins, histamines, kinins, and interleukins, in endometriotic implants are involved in the activation of peritoneal nociceptors and in pain mediation. However, the pathophysiology of the peritoneal endometriosis related pelvic pain is still not well understood.Research has been focused on sensory nerve sensory nerve fibers A8, sensory fibers C in recent years. There are some reports about neural anatomy mechanisms in endometriosis pain. The role of neurotransmitter systems in pathogenesis of endometriosis is still unknown. There are lots of molecules called "pain related substances", such as nerve growth factor (NGF), interleukins and tumor necrosis factor-α. NGF belongs to neurotrophin family, which promotes the survival of neurons. It has been found that the binding of NGF with its receptor causes self-induced phosphorylation and triggers variety of biological effects.NGF binds to2types of receptors:tyrosine kinase A (TrkA) and the p75neurotrophin receptor (p75NTR). In adults, NGF is not required for survival, but plays a crucial role in the generation of acute and chronic inflammatory pain. Levels of NGF have been shown to increase dramatically in inflammatory tissues, and the enhanced transport of NGF activates and sensitizes primary afferent neurons that express TrkA. With regard to discogenic low back pain in humans, it has been demonstrated that painful discs have higher levels of NGF than asymptomatic intervertebral discs. More recently, it was demonstrated that painful discs have nerve fibers expressing TrkA, and microvascular blood vessels expressing NGF. Thus, the NGF-TrkA pathway is important in inflammatory pain originating from degenerated intervertebral discs. However, it is not clear whether it is the interaction of NGF with TrkA, p75NTR NGFRp75, or both, that is important for discogenic low back pain. More recent reports have shown that nerve injury increased the expression and axonal transport of p75NTR in uninjured primary afferents, and functional inhibition of p75NTR suppressed injury-induced neuropathic pain.However, the research about the relationship between different types of endometriosis and its surgery findings have not yet been fully unified. It needs more clinical research.Objectives:To explore NGF and its receptor TrkA, p75expression in different types of endometriosis lesions, as well as the relationship between the degrees of pain.Materials and Methods:1. Objects:97endometriosis lesions from women with endometriosis and16normal uterosacral ligament and normal endometrium from women without endometriosis (with uterine leiomyoma and without pain symptoms).2. Methods:2.1Determination of NGF and its receptors:Immunohistochemistry was performed to observe NGF, TrkA and p75of endometriosis lesions.2.2Evaluation of pain degree and types:Using a standardized questionnaire with a visual analogue scale (VAS), the severity of pain symptoms, such as pelvic pain and dysmenorrhea, was documented before surgery. The pain scale was subdivided into10grades."No pain" was indicated at the left side of the scale and "the maximum pain you could imagine" at the right side of the scale. The patient should point out the severity of pain and the type of pain. We define patients with pelvic pain during menstruation as dysmenorrhea, and with persistent pelvic pain lasting more than six month as chronic pelvic pain.3. Statistical analysis:All data were managed with SPSS16.0for windows. Non-parametric test was used for statistical analysis. Two-tailed test with p<0.05were considered significance.Results:1. The expression of NGF, TrkA and p75in DIE uterosacral ligament lesions is higher than the normal uterosacral ligament p<0.05), but only the expression of p75in DIE uterosacral ligament lesions with severe dysmenorrheal is higher than the patient without dysmenorrheal (p<0.05).2. There was significant difference in NGF, TrkA and p75expression between eutopic endometrium and endometrium without endometriosis (p<0.05), but only the expression of p75in eutopic endometrium with severe dysmenorrheal is higher than the patient without dysmenorrheal (p<0.05).3. There was no significant difference in NGF and TrkA expression between ovarian endometiosis with severe dysmenorrheal and without dysmenorrheal (p>0.05), but the expression of p75is significantly different between the two groups (p<0.05).4. The expression of NGF in endometriosis lesions is as follows:deep infiltrating endometriosis>ovarian endometiosis>abdominal node. Therefore, there was no significant difference in the TrkA expression of three different endometriosis lesions, the expression of p75in DIE uterosacral ligament is higher than the other two groups (p<0.05).Conclusion:1. Our study found that the expression of NGF and its receptors is higher in patients with endometriosis than without endometriosis, it indicated that NGF and its receptors may be closely related to the mechnism of endometriosis.2. In relative to the endometriosis without dysmenorrheal, the expression of p75is significantly higher in DIE, OEM and eutopic endometrium with severe dysmenorrheal, so p75may be a significant indicator and play a role in the progress of endometriosis pain.3. The expression of NGF and p75in DIE is higher than the two others endometriosis, it was showed that NGF and p75may have an important effect on the pathogenesis of DIE. |
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