Sexual and regional differences in myosin heavy chain expression in the rat external urethral sphincter
Sexual and regional differences in myosin heavy chain expression in the rat external urethral sphincter
复制标题
大鼠尿道外括约肌肌球蛋白重链表达的性别和区域差异
DOI：
10.1002/ar.23627
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
W. Tsumiyama
中科院分区：
文献类型：
--
作者：
T. Tsumori;W. Tsumiyama
尿道外括约肌是一种独特的尿道周围横纹肌，在尿失禁中起着至关重要的作用，需要对其形态学进行全面了解，以确定尿失禁的病理生理学基础并找到合适的治疗方法。性别之间和物种之间的差异，关于纤维类型目前仍然存在争议。本研究使用三重免疫荧光标记可视化一个慢（1型）和两个快速（2A型和2B型）肌球蛋白亚型在大鼠尿道外括约肌从两种性别。在雌性大鼠中，2A型纤维在整个括约肌中占主导地位，2B型纤维仅限于外尿道括约肌的近端三分之一。1型纤维存在于近腔，并集中在近端和远端段的括约肌。虽然大多数男性尿道外括约肌由2B型纤维组成，但2A型纤维在括约肌近端三分之一的这些纤维中混杂，并且存在少数1型纤维，其仅限于近端段的近腔区域。性腺切除后，两种性别的纤维类型组成及其面密度发生了变化。1型纤维的面密度在卵巢切除的女性中显著增加，尤其是在远段。切除双侧睾丸的雄性大鼠，1型和2A型纤维的面密度显著增加，而2B型纤维的面密度显著降低。这些结果表明，肌球蛋白重链在大鼠尿道外括约肌的表达是性别二态性，并显示出区域差异。Anat Rec，2017.© 2017 Wiley Periodicals，Inc. Anat Rec，300：2058-2069，2017。© 2017 Wiley Periodicals，Inc.
The external urethral sphincter is a unique striated muscle surrounding the urethra that plays a crucial role in urinary continence, and a comprehensive understanding of its morphology is needed to determine the pathophysiology underlying urinary incontinence and find suitable therapies. Differences between the sexes and among species regarding the fiber types present remain controversial. This study used triple immunofluorescence labeling to visualize one slow (Type 1) and two fast (Types 2A and 2B) myosin isoforms in rat external urethral sphincters from both sexes. Type 2A fibers predominated throughout the sphincter and Type 2B fibers were restricted to the proximal one‐third of the external urethral sphincter in the female rats. Type 1 fibers were present adluminally and were concentrated in the proximal and distal segments of the sphincter. While most of the male external urethral sphincter comprised Type 2B fibers, Type 2A fibers intermingled among these fibers in the proximal one‐third of the sphincter, and a few Type 1 fibers were present that were restricted to the adluminal region of the proximal segment. The fiber‐type compositions and their areal densities changed in both sexes after gonadectomy. The areal density of the Type 1 fibers increased significantly in the ovariectomized females, especially in the distal segment. In the orchidectomized males, the areal densities of the Types 1 and 2A fibers increased significantly, but that of the Type 2B fibers decreased. These results indicate that myosin heavy chain expression in the rat external urethral sphincter is sexually dimorphic and shows regional differences. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:2058–2069, 2017. © 2017 Wiley Periodicals, Inc.