ABSTRACT
<p><b>OBJECTIVE</b>To study the function of zinc in preventing human sperm from being damaged by sodium nitroprusside (SNP), an external NO donor.</p><p><b>METHODS</b>Analyses were made of the function of zinc in protecting sperm from being influenced by SNP in such aspects as sperm motility, head-tail connection and the breakage of sperm DNA chain by using phase-contrast microscope and single cell gel electrophoresis (SCGE).</p><p><b>RESULTS</b>Sperm motility was obviously inhibited by SNP. The percentage of comet cells increased significantly but the stability of sperm head-tail connection decreased. Zinc could promote sperm motility, protect the DNA chain and prevent the sperm head-tail connection from breaking.</p><p><b>CONCLUSION</b>Zinc can protect sperm from being damaged by NO. Its mechanism may be related to the mercaptol group of sperm chromatin.</p>