Divergent effect of fast- and slow-releasing H(2)S donors on boar spermatozoa under oxidative stress

Hydrogen sulphide (H(2)S) 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 H(2)S 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 Na(2)S and GYY4137, which are fast- and slow-releasing H(2)S donors, respectively, and ii) to test whether H(2)S donors are able to protect spermatozoa against oxidative stress. We found that Na(2)S and GYY4137 show different antioxidant properties, with the total antioxidant capacity of Na(2)S being mostly unstable and even undetectable at 150 µM. Moreover, both H(2)S 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 Na(2)S was beneficial at the lowest concentration but detrimental at the highest. Our findings show that Na(2)S and GYY4137 have different antioxidant properties and suggest that both H(2)S donors might be used as in vitro therapeutic agents against oxidative stress in sperm cells, although the optimal therapeutic range differs between the compounds.