Ultrastructure of spermatozoa with abnormal morphology and predominantly single-stranded DNA

Semen samples from two infertile men showed normal numbers of cells, but the majority of the spermatozoa were abnormal in shape and had very poor motility. The majority of the spermatozoa showed red fluorescence when stained with acridine orange, indicating the presence of single-stranded DNA. At the ultrastructural level the chromatin was decondensed to various degrees. The acrosomes were either lacking or highly abnormal in appearance. Abnormal tail elements were liberally scattered all over in the abnormal cells. Based on these findings and previous reports, it is suggested that certain infections and exposure to various toxic substances can result in such changes.