Cyclic Changes of Nerve Fibers in Human Endometrium

Tatsuo Tomita,Kuni Mah

doi:10.4236/ojpathology.2014.42011

Abstract

Objective: The presence of nerve fibers in human endometrium remains unsettled but recent immunocytochemical studies have shown that there was increased innervation in the endometrium from women with endometriosis and some nerve fibers in the normally cycling human endometrium. In the current study, we used uterine tissue cryosections from normal cycling women, which previously provided better immunocytochemical staining for lymphatic vessels than in paraffin sections. Materials and Methods: A total of 16 cases from normally cycling women were included representing menstrual, early proliferative, early to late secretary phase. Neurofilament and CD 56 were used as immunocytochemical markers for nerve fibers with cryosections. Results: There were consistent presence of nerve fibers in myometrium and basalis. Few small nerve fibers were identified in early proliferative endometrium and more nerve fibers were present in lower-half functionalis from mid-secretary phase. Late-secretary functionalis showed less nerve fibers in the upper-half than the lower-half functionalis, implying growing nerve fibers from lower functionalis to upper functionalis in late-secretary phase. Conclusion: Nerve fibers appeared to cyclically grow from basalis to lower functionalis and then from lower functionalis to upper functionalis concomitantly with blood vessels in normally cycling human endometrium. These cycling endometrial nerve fibers consisted mostly of nonmyelinated small nerve fibers, which may transmit pelvic pain in the normally cycling women.

Highlights

The presence of nerve fibers in human endometrium is controversial and still remains unsettled [1] [2]
The presence of nerve fibers was implicated on a pain source of endometriosis, in which small nerve fibers were identified throughout basalis and functionalis from women with endometriosis whereas nerve fibers were not observed in functionalis in any women without endometriosis by immunocytochemical staining using protein gene product 9.5 (PGP 9.5) and neurofilament (NF) [3]-[5]
Using PGP 9.5, another study reported the presence of small nerve fibers in functionalis, basalis and myometrium, which were higher in women hormonally untreated than those hormonally treated women with endometriosis [7]

Summary

Introduction

The presence of nerve fibers in human endometrium is controversial and still remains unsettled [1] [2]. Using PGP 9.5, another study reported the presence of small nerve fibers in functionalis, basalis and myometrium, which were higher in women hormonally untreated than those hormonally treated women with endometriosis [7]. More reports support the presence of nerve fibers in normal functionalis in addition to basalis and myometrium [6] [7]. All the previous immunocytochemical studies had been performed with routinely formalin-fixed and paraffin-embedded tissues [2]-[6], which may not detect all nerve fibers whereas frozen section immunocytochemistry revealed consistent presence of lymphatic vessels [8] and venous vessels [9] in endometrium from normally cycling women. The current study aimed to detect the presence of nerve fibers in normally cycling endometrium of different menstrual cycle using NF and CD 56 immunostaining in basalis, functionalis and myometrium. CD 56 expression is compatible to N-CAM and is expressed in thin nerve fibers, fine varicose and sensory nerve endings, cell membrane of ganglion cells and young striated muscle cells but thick nerve fibers, perikarya of ganglion cells and adult striated muscle fibers were reportedly CD 56 negative [11]

Materials and Methods

Results

Discussion