A novel third mesh-like myometrial layer connects the longitudinal and circular muscle fibers -A potential stratum to coordinate uterine contractions-
A novel third mesh-like myometrial layer connects the longitudinal and circular muscle fibers -A potential stratum to coordinate uterine contractions-
复制标题
DOI：
10.1038/s41598-020-65299-0
复制
发表时间：
2020-05-19
影响因子：
4.6
通讯作者：
Fujiwara, Hiroshi
中科院分区：
文献类型：
--
作者：
Kagami, Kyosuke;Ono, Masanori;Fujiwara, Hiroshi
子宫肌层周期性收缩是实现胚胎着床分娩的重要子宫功能之一。虽然众所周知，哺乳动物子宫肌层由纵向(外层)和环形(内层)两层组成，但协调两种肌肉收缩以产生蠕动运动的确切机制仍不清楚。最近，通过使用我们的改良的Clear Un阻塞脑成像鸡尾酒和计算分析(CUBE)组织清除方法，我们使用增强型绿色荧光蛋白(EGFP)转基因小鼠和光片显微镜获得了透明小鼠卵巢的高对比度三维图像。因此，为了研究子宫内外肌层纤维之间的准确解剖联系，我们使用透明的小鼠子宫观察了子宫肌层的整个结构。通过这种方法，我们发现了一种新的肌层，即子宫肌层的中间层，它在解剖学上连接着传统的外纵肌和内环肌。这一新的层被可视化为网状结构，这种结构从近端到远端贯穿整个子宫。在该区域，CD31阳性血管大量分布在网状肌纤维周围。此外，CD34阳性的子宫端细胞和微管蛋白β3阳性的神经纤维紧密地分布在这一中间层。这些发现表明存在一种新的网状层，连接纵向和环状肌层，并提示其在子宫肌层收缩中的协调作用。
Periodic myometrial contraction is one of the important uterine functions to achieve embryo implantation and parturition. Although it is well-known that the mammalian myometrium is composed of longitudinal (outer) and circular (inner) layers, the precise mechanisms that coordinate both muscular contractions to produce peristaltic movements remain unclear. Recently, by treatment with our modified Clear Unobstructed Brain Imaging Cocktails and Computational analysis (CUBIC) tissue-clearing method, we obtained well-contrasted three-dimensional images of the transparent murine ovary using enhanced green fluorescent protein (EGFP) transgenic mice and light-sheet microscopy. Consequently, to investigate accurate anatomical connections between outer and inner myometrial fibers, we observed whole structures of the myometrium using a transparent murine uterus. By this method, we identified a novel muscle layer, a middle layer of the myometrium, which anatomically connects the conventional outer longitudinal and inner circular muscles. This new layer was visualized as a mesh-like structure and this structure was observed throughout the whole uterus from proximal to distal sites. In this area, CD31-positive vessels were abundantly localized around the mesh-like muscle fibers. In addition, CD34-positive uterine telocytes and tubulin beta -3-positive nerve fibers were closely located in this middle layer. These findings indicate the presence of a novel mesh-like stratum that connects longitudinal and circular muscle layers, and suggest its coordinating role in myometrial contractions.