The effect of dopamine on bovine sperm function

Abstract

Despite the frequent use of cryopreservation in preserving the sperm of threatened species, effective post-cryopreservation methods are still sub-optimal. However, treatment with dopamine has shown promising evidence as an effective extender to sperm viability, given its known impact on sperm motility during ejaculation (Urra et al. 2014; Alwaal, Breyer, Lue 2015). To characterize the interaction between dopamine and sperm function post-cryopreservation, frozen-thawed bovine sperm were incubated in four concentrations of dopamine for 30 minutes: 0 uM (T30 control), 1 uM (low), 5 uM (intermediate), and 10 uM (high). Acrosomal integrity, motility, viability, and ATP levels were measured to assess sperm health following incubation. Due to the physiological advantages of dopamine on bovine sperm, we hypothesized a positive effect on motility and ATP production. Our data did not support our original hypothesis and instead showed that, on average, a low dose of dopamine caused an increase in ATP concentration and the incidence of premature acrosomal reaction compared to the pre-incubation control. Interestingly, a low dose of dopamine also appeared to cause a decrease in sperm motility, whereas sperm incubated in an intermediate dose of dopamine exhibited the highest percentage of motile sperm per sample. This discrepancy could indicate that ATP production is not unconditionally linked to sperm motility. Based on this data, dopamine appears to have a positive effect on ATP production and acrosomal integrity but a negative effect on motility. Further research is necessary to uncover the significance of these findings.