Effects of long-term in vitro incubation of human spermatozoa: functional parameters and catalase effect

Prolonged incubation of human spermatozoa can have deleterious effects on s perm function. The aim of this paper was to describe the effects of a prolo nged in vitro incubation, under similar conditions to those employed in hum an assisted reproduction, on various sperm functional parameters, and to in vestigate the effect of an antioxidant (catalase) on this system. Freshly c ollected ejaculates from 20 healthy donors were studied. Samples were divid ed into two aliquots: the first was incubated with Ham's F10 containing 3.5 % HAS, and the second was incubated in the same medium plus catalase (100 u nits ml(-1)). All experiments were carried out with spermatozoa isolated us ing the swim-up technique. Spermatozoa recovered from the supernatant after 1 h (T1) of incubation in 5% CO2 in air at 37 degreesC, and after 5 h (T6) , 23 h (T24) and 47 h (T48), were evaluated for concentration, motion param eters including hyperactivation (computer-assisted analysis), viability, AT P concentration, reactive oxygen species (ROS) generation, DNA integrity (a cridine orange), and acrosome reaction (AR). The major alteration observed in sperm function during the prolonged in vitro incubation was a reduction in the number of motile spermatozoa, together with an impairment: in the qu ality of sperm movement. ROS levels increased with the incubation time. No substantial modifications of sperm viability, chromatin condensation and AR inducibility were observed. The addition of catalase to the medium, while keeping ROS values within baseline levels, did not prevent the loss of moti lity or the corresponding increase in ATP.