Strasser H, Tiefenthaler M, Steinlechner M, Eder I, Bartsch G, Konwalinka G
Departments of Urology, Internal Medicine and Forensic Medicine, University of Innsbruck, Innsbruck, Austria.
J Urol. 2000 Nov;164(5):1781-5.
To our knowledge the exact age dependent morphological and functional changes of the sphincter mechanism have not been investigated. Therefore, cell densities of the urethra and the urethral rhabdosphincter across various age groups, and the appearance of apoptosis were examined to explore the changes in these structures during the aging process.
Specimens were obtained from 16 male and 7 female cadavers 5 weeks to 92 years old. Histological sections were taken from 3 different levels of the rhabdosphincter and urethra. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling method was used to detect apoptosis in the urethra and rhabdosphincter. In all specimens relative volume densities of the striated muscle fibers, apoptotic indexes and diameters of the rhabdosphincter and urethra were determined.
An age dependent increase of apoptosis of the striated muscle fibers of the rhabdosphincter led to a dramatic decrease in the number of striated muscle cells. In the 5-week-old neonate 87.6% and in the 91-year-old woman 34.2% of the rhabdosphincter consisted of striated muscle cells. Overall, a direct linear correlation between the age of the specimens and decrease in volume densities of the striated muscle cells was evident.
The dramatic decrease in the number of striated muscle cells in the rhabdosphincter of the elderly due to apoptosis represents the morphological basis for the high incidence of stress incontinence in this population.
据我们所知，尚未对括约肌机制随年龄增长的确切形态和功能变化进行研究。因此，研究了不同年龄组尿道及尿道横纹括约肌的细胞密度以及凋亡情况，以探讨衰老过程中这些结构的变化。
从16具男性尸体和7具女性尸体（年龄从5周大至92岁）获取标本。从横纹括约肌和尿道的3个不同水平取组织学切片。采用末端脱氧核苷酸转移酶介导的脱氧尿苷三磷酸缺口末端标记法检测尿道和横纹括约肌中的凋亡情况。测定所有标本中横纹肌纤维的相对体积密度、凋亡指数以及横纹括约肌和尿道的直径。
横纹括约肌横纹肌纤维凋亡随年龄增长而增加，导致横纹肌细胞数量显著减少。在5周大的新生儿中，87.6%的横纹括约肌由横纹肌细胞组成，而在91岁的女性中这一比例为34.2%。总体而言，标本年龄与横纹肌细胞体积密度降低之间存在明显的直接线性关系。
老年人横纹括约肌中横纹肌细胞数量因凋亡而显著减少，这是该人群压力性尿失禁高发的形态学基础。
