Apoptosis in human ejaculated sperm cells (notulae seminologicae 9)

Abstract

In this work we apply the Hoechst 33258 DNA staining, the TUNEL procedure and conventional electron microscopy to study the ejaculate of fertile and infertile men, in order to detect apoptosis in human sperm cells. We have observed that apoptosis is abnormally frequent in the sperm cells of the ejaculate of sterile men, and that it shows the classical biochemical and ultrastructural pattern in spermatozoa, spermatids and apoptotic bodies. These characteristics, involving the chromatin, the nuclear envelope, the plasma membrane, the presence of cytoplasmic vacuoles and the status of mitochondria, are consistent whatever the pathology of the patient is. What is varying is the percentage of the apoptotic sperm cells, that is about 0.1% in fertile controls, and increases up to about 10% in varicocele, infected (including AIDS), "round headed' patients, to 20% in cryptorchid men, to 25% in immature patients, and to 50% in testicular seminoma carriers. Obviously in each category the frequence of apoptotic cells increases concomitantly with the degree of the affection. The present demonstration not only extends to human spermiogenetic epithelium the natural presence of apoptosis, which starts in the testis and is revealed in the ejaculate, but also explains many abnormal ultrastructural sperum patterns hitherto unexplained in fertile and infertile individuals.