Divergent effect of fast- and slow-releasing H2S donors on boar spermatozoa under oxidative stress.

Hydrogen sulphide (H2S) is involved in the physiology and pathophysiology of different cell types, but little is known about its role in sperm cells. Because of its reducing properties, we hypothesise that H2S protects spermatozoa against the deleterious effects of oxidative stress, a condition that is common to several male fertility disorders. This study aimed i) to determine the total antioxidant capacities of Na2S and GYY4137, which are fast- and slow-releasing H2S donors, respectively, and ii) to test whether H2S donors are able to protect spermatozoa against oxidative stress. We found that Na2S and GYY4137 show different antioxidant properties, with the total antioxidant capacity of Na2S being mostly unstable and even undetectable at 150 µM. Moreover, both H2S donors preserve sperm motility and reduce acrosome loss, although the effects were both dose and donor dependent. Within the range of concentrations tested (3-300 µM), GYY4137 showed positive effects on sperm motility, whereas Na2S was beneficial at the lowest concentration but detrimental at the highest. Our findings show that Na2S and GYY4137 have different antioxidant properties and suggest that both H2S donors might be used as in vitro therapeutic agents against oxidative stress in sperm cells, although the optimal therapeutic range differs between the compounds.