Perucchini Daniele, DeLancey John O L, Ashton-Miller James A, Peschers Ursula, Kataria Tripti
Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, USA.
Am J Obstet Gynecol. 2002 Mar;186(3):351-5. doi: 10.1067/mob.2002.121089.
This study was undertaken to test the null hypothesis that the number of striated muscle fibers in the ventral wall of the female urethra remains constant with increasing age.
The urethra and surrounding tissues from 25 female cadavers, mean age 52 years (+/-SD 18, range 15-80 years), were selected for this study. Each specimen was divided along the midsagittal plane, and a Masson trichrome histologic section was prepared. A systematic count of striated muscle fibers in the ventral wall was then obtained at each decile of urethral length.
A decrease in the total number of fibers within the sampled area was found with increasing age. The mean of the total fibers across all urethrae was 17,423 (+/-SD 9,624, range 4,788-35,867). Over the life span, an average of 364 fibers (2%) were lost per year (95% CI 197-531; P <.001). Mean fiber density was 671 (+/- SD 296, range 228-1374) fibers/mm2 and decreased by 13 fibers/mm2 per year (95% CI 8-17; P <.001). The mean lesser fiber diameter was 24 microm and did not change significantly with age ( P =.3).
The number and density of urethral striated muscle fibers decline with age.
本研究旨在检验女性尿道腹侧壁横纹肌纤维数量随年龄增长保持恒定这一零假设。
选取25具平均年龄52岁（标准差18，年龄范围15 - 80岁）的女性尸体的尿道及周围组织进行本研究。每个标本沿矢状面切开，制备一张马松三色组织学切片。然后在尿道长度的每十分位数处对腹侧壁的横纹肌纤维进行系统计数。
发现随着年龄增长，采样区域内纤维总数减少。所有尿道纤维总数的平均值为17,423（标准差9,624，范围4,788 - 35,867）。在整个生命周期中，平均每年有364根纤维（2%）丢失（95%置信区间197 - 531；P <.001）。平均纤维密度为671（标准差296，范围228 - 1374）根纤维/mm²，且每年减少13根纤维/mm²（95%置信区间8 - 17；P <.001）。较小纤维的平均直径为24微米，且随年龄无显著变化（P =.3）。
尿道横纹肌纤维的数量和密度随年龄下降。
