精子碱性单细胞凝胶电泳法优化条件的建立及效果分析

Optimization of sperm alkaline single-cell gel electrophoresis

目的:探讨精子碱性单细胞凝胶电泳法(SCGE)的主要影响因素,并优化条件,以利于标准化。方法:采用不同浓度H2O2处理精子,碱性SCGE检测精子DNA碎片(SDF),探讨凝胶层数、DNA解旋及电泳时的p H、DNA解旋及电泳时间、计数精子数对结果的影响,分析优化后方法的重复性,并用于检测40例精液标本。结果:3层琼脂糖凝胶可降低本底,DNA解旋及电泳缓冲液最佳p H值为10,最佳DNA解旋及电泳时间分别为40 min和30 min,计数50个精子即可保证结果的可靠性。优化后的碱性SCGE,用尾部DNA含量百分比表示,其批内、批间变异系数(CV)分别为3.12%、7.13%,用DNA损伤得分表示,其批内、批间CV分别为2.38%和6.09%。与健康生育男性相比,少弱畸形精子症不育男性精液SDF显著升高(P<0.05)。结论:优化后的精子碱性SCGE,重复性好,易于标准化,可用于不育男性SDF检测,适合在临床推广应用。

Objective： To investigate the main factors that influence the results of sperm alkaline single-cell gel electrophoresis （SCGE） , optimize the conditions, and standardize its procedures. Methods： Using alkaline SCGE, we detected the DNA fragments of sperm treated with different concentrations of H2O2 and determined the influences of the number of agarose gel layers, pH during DNA unwinding and electrophoresis, the time of DNA unwinding and electrophoresis, and cumulative sperm number on the results of sperm alkaline SCGE. Then we optimized the procedures, analyzed the repeatability of the optimized method, and examined 40 semen samples using the method. Results： Three agarose gel layers could reduce the background. The optimal pH during DNA unwinding and electrophoresis was 10, and the best times for DNA unwinding and electrophoresis were 40 min and 30 min, respectively. Fifty sperm were adequate to ensure the reliability of the results. Based on the percentage of tail DNA, the intra- and inter-assay repeatabil- ities of the optimized sperm alkaline SCGE were 3.12% and 7.13% , and by the DNA damage score, they were 2.38% and 6.09% , respectively. Sperm DNA fragments were significantly increased in the infertile patients with oligoasthenoteratozoospermia as compared with healthy fertile males （ P 〈 0.05 ）. Conclusion ： The optimized sperm alkaline SCGE, highly repeatable and easy to be standardized, can be applied to the clinical detection of sperm DNA fragmentation in infertile men.