人精子中芳香化酶表达与精子功能的关系

Correlation between Expression of Aromatase in Human Ejaculated Spermatozoa and Fertilizing Ability

目的:研究精子细胞色素P450芳香化酶(P450arom)的表达及其与精子功能状态和受精力的关系。方法:以人精子穿透去透明带金黄地鼠卵异种体外受精试验(SPA)检测精子受精力;以三色法染色观察精子顶体反应(AR)的发生率。采用RT-PCR,用P450arom/GAPDH光密度值的比值代表P450arom的表达水平。结果:精子P450arom表达水平与受精率有一定的相关性(生育组r=0.5622;不育组r=0.6071)。正常男性与不明原因不育症患者精子P450arom/GAPDH比值分别为0.60±0.29,0.39±0.16,有显著差异(P<0.02)。P450arom表达水平与精子AR的发生率也有一定相关性(生育组r=0.5817;不育组r=0.5535)。结论:人精子中存在着P450arom表达产物;P450arom可能与精子功能有一定关系;P450arom表达异常可能与一些不明原因不育有关。

Objective: To investigate whether P450 aromatase transcripts is correlated with the fertilizing ability in human ejaculated spermatozoa. Methods: Semen samples from 16 fertile men and 18 infertile men with normal semen parameters were studied. Total RNA of spermatozoa purified from each sample underwent RT-PCR to amplify specific mRNA transcripts of P450arom and those of GAPDH, glyceraldehyde-3-phosphate dehydroge- nase (GAPDH), which was used as control for the integrity of the RNA. After electrophoresis on a 1.5% agarose gel, the products of RT-PCR were visualized under UV light, photographed and analyzed with a KODAK 1D software. The staining intensities of the P450arom and GAPDH signals were determined respectively and the ratio of them was used to indicate the expression of P450 aromatase in each purified spermatozoa. Using a sperm penetration of zona-free hamster egg assay (SPA) and a triple-stain technique, the fertilizing capability and the acrosome reaction (AR) of each sample was evaluated respectively. Results: The penetration rate of SPA was correlated with the P450arom transcripts (r=0.5622 in fertile men and r=0.6071 in infertile men). P450arom/GAPDH ratio of sperma- tozoa in fertile men was significantly higher than that of infertile men (0.60±0.29 vs 0.39±0.16, P<0.02). The rate of acrosome-reacted spermatozoa was correlated with the level of P450arom expression (r=0.5817 in fertile men and r=0.5535 in infertile men). Conclusion: Our observations confirmed that human ejaculated sperma- tozoa contain P450arom specific transcripts. It suggests that the presence of P450arom is possibly related to sperm function. Disturbance of P450 arom expression in spermatozoa may be one of the reasons for infertile.