Unit of Reproductive Physiology, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang 310013, China.
Hum Reprod. 2010 Feb;25(2):317-27. doi: 10.1093/humrep/dep406. Epub 2009 Nov 18.
Our previous studies have demonstrated the cystic fibrosis transmembrane conductance regulator (CFTR) is important for capacitation and male fertility in mouse and guinea pig spermatozoa. However, the exact function of CFTR on human sperm fertilizing capacity, and correlation with sperm quality has not been established. The present study may shed light on some unexplained male infertility, and on a possible new method for diagnosis of male infertility and strategy for male contraception.
To assess the effect of CFTR on human sperm fertilizing capacity, we examined sperm capacitation and the acrosome reaction using chlortetracycline staining, analyzed sperm hyperactivation by computer-assisted semen analysis (CASA), measured intracellular cAMP levels using ElA and evaluated sperm penetration of zona-free hamster eggs assay in fertile men. The percentage of spermatozoa expressing CFTR from fertile, healthy and infertile men (mainly teratospermic, asthenoteratospermic, asthenospermic and oligospermic) was conducted by indirect immunofluorescence staining.
Progesterone significantly facilitated human sperm capacitation and ZP3 triggered the acrosome reaction, both were significantly inhibited by CFTR inhibitor-172 (CFTRinh-172; 10 nM-1 microM) in a dose-dependent manner. The presence of 100 nM CFTRinh-172 markedly depressed intracellular cAMP levels, sperm hyperactivation and sperm penetration of zona-free hamster eggs. In addition, the percentage of spermatozoa expressing CFTR in the fertile men was significantly higher than healthy and infertile men categories (P < 0.01).
CFTR is essential for human sperm fertilizing capacity and the impairment of CFTR expression in spermatozoa is correlated with a reduction of sperm quality. These results suggest that defective expression of CFTR in human sperm may lead to the reduction of sperm fertilizing capacity.
我们之前的研究表明囊性纤维化跨膜电导调节因子（CFTR）对小鼠和豚鼠精子的获能和男性生育力很重要。然而，CFTR 对人类精子受精能力的确切功能，以及与精子质量的相关性尚未确定。本研究可能为一些原因不明的男性不育症提供线索，并为男性不育症的诊断和男性避孕策略提供一种新的方法。
为了评估 CFTR 对人类精子受精能力的影响，我们使用氯四环素染色法检查精子获能和顶体反应，通过计算机辅助精液分析（CASA）分析精子超激活，使用 ELISA 测量细胞内 cAMP 水平，并评估精子穿透无透明带仓鼠卵的能力在生育力正常的男性中。通过间接免疫荧光染色，检测来自生育力正常、健康和不育男性（主要是畸形精子症、弱精子症、少精子症和寡精子症）的精子中 CFTR 的表达率。
孕酮显著促进了人精子的获能，ZP3 触发了顶体反应，这两种反应均被 CFTR 抑制剂-172（CFTRinh-172；10 nM-1 μM）以剂量依赖性方式显著抑制。存在 100 nM CFTRinh-172 时，细胞内 cAMP 水平、精子超激活和精子穿透无透明带仓鼠卵的能力显著降低。此外，生育力正常男性的精子中 CFTR 的表达率明显高于健康和不育男性（P <0.01）。
CFTR 对人类精子的受精能力是必不可少的，精子中 CFTR 表达的损害与精子质量的降低有关。这些结果表明，人类精子中 CFTR 的表达缺陷可能导致精子受精能力下降。
