Abstract
The process of human sperm decondensation has been studied in vitro in cytoplasmic extracts prepared from unfertilized Xenopus laevis eggs. The chromatin decondensation-recondensation cycle was divided into four stages according to chromatin appearance. Spermatozoa from normospermia and as-thenospermia were evaluated according to their capacity to reach these stages, and their DNA integrity was assessed by acridine orange (AO) staining. We observed a significant difference between normospermia and asthenozoospermia in the ability to achieve the cycle of chromatin decondensation-recondensation. These results correlated with AO staining. The role of human protamine 1 degradation in the decondensation process was evaluated by immunostaining. It was found not to be a prerequisite for the earlier stage of chromatin decondensation and it was not implied in the latest stages of pronu-clear development.