Missing generations of spermatocytes and spermatids in seminiferous epithelium contribute to low efficiency of spermatogenesis in humans.
Missing generations of spermatocytes and spermatids in seminiferous epithelium contribute to low efficiency of spermatogenesis in humans.
复制标题
生精上皮中精母细胞和精子细胞世代的缺失导致人类精子发生效率低下。
DOI：
10.1095/biolreprod47.6.1091
复制
发表时间：
1992
影响因子：
3.6
通讯作者：
Williams,JD
中科院分区：
文献类型：
--
作者：
Johnson,L;Chaturvedi,PK;Williams,JD
人类每克薄壁组织的每日精子产量（DSP/g）仅为大多数物种（包括大鼠和非人灵长类动物）的25或35%。为了解释人类精子发生的低效率，在具有不同效率的男性中，确定了每个精子发生阶段的生殖细胞（精母细胞和精子细胞）的代数以及每代中这些生殖细胞的数量。在尸检时获得睾丸，通过戊二醛血管灌注固定，进一步固定在锇中，并包埋在Epon 812中，然后用甲苯胺蓝对0.5 μm切片进行染色。对输卵管横截面进行拍照，并由两名观察员确定生精阶段。按DSP/g分为3组。高、中DSP/g组的精母细胞和精子细胞的代数（2.01 ± 0.05）和（1.77 ± 0.04）均显著高于低DSP/g组（1.45 ± 0.15）（p< 0.05）。与最佳值3相比，所有组的精母细胞和精子细胞的代数均较低。在这些人中，每个横截面的这些代数与DSP/g相关（r= 0.85;p< 0.01）。高DSP/g组的每个横截面的精母细胞、精子细胞和生殖细胞的组合数量高于低DSP/g组（p< 0.01）。每个横截面的生殖细胞的组合数目与DSP/g相关（r= 0.85;p< 0.01）。在I期至V期，高DSP/g组与低DSP/g组相比，生殖细胞的组合数量更高，但这种差异仅在IV期和V期具有显著性。这些数据表明，沿着人类曲细精管长度缺失生殖细胞的世代沿着（由管状横截面中缺失的那些注意到），再加上每一代内细胞数量的缺乏，与大多数其他物种相比，导致精子发生效率低。
Daily sperm production per gram parenchyma (DSP/g) in humans is only 25 or 35% of that for most species including rats and nonhuman primates. To explain the low efficiency of spermatogenesis in humans, the number of generations of germ cells (spermatocytes and spermatids) and the number of these germ cells in each generation were determined for each spermatogenic stage in men with varied efficiencies. Testes were obtained at autopsy, fixed by vascular perfusion with glutaraldehyde, further fixed in osmium, and embedded in Epon 812 before 0.5-µm sections were stained with toluidine blue. Tubular cross sections were photographed, and spermatogenic stages were determined by two observers. Testes were divided into three groups on the basis of DSP/g. The number of generations of spermatocytes and spermatids was greater (p< 0.05) in the high (2.01 ± 0.05) and intermediate (1.77 ± 0.04) than in the low (1.45 ± 0.15) DSP/g group. All groups had a lower number of generations of spermatocytes and spermatids compared to the optimum value of three. The number of these generations per cross section was related (r= 0.85;p< 0.01) to DSP/g in these men. The number per cross section of spermatocytes, spermatids, and the combined number of germ cells was higher (p< 0.01) in the high than in the low DSP/g group. The combined number of germ cells per cross section was related (r= 0.85;p< 0.01) to DSP/g. The combined number of germ cells was higher in the high versus the low DSP/g group in stages I through V, but this difference was significant only in stages IV and V. These data reveal that missing generations of germ cells along the length of human seminiferous tubules (noted by those missing in tubular cross sections), coupled with a paucity in number of cells within each generation, contributes to the low efficiency of spermatogenesis compared to that of most other species.