Efficacy and safety of papaverine as an in vitro motility enhancer on human spermatozoa

Purpose: The aim of this study was to examine the ability and safety of papaverine supplementation for in vitro sperm motility enhancement. In addition, sperm motility enhancement of papaverine was compared to pentoxifylline and theophylline. The post-thaw spermatozoa were used as an asthenozoospermia model. Methods: Post thaw sperm suspensions were divided into two groups: papaverine (100 μmol/L) and control, and each was investigated in two subgroups of 30- and 60-min exposure times. Detailed motility parameters were detected using a computerized sperm motility analyzer. Acrosomal status, viability, apoptosis, and DNA fragmentation were evaluated by flow cytometry. Furthermore, the motility-enhancing capacity of papaverine, pentoxifylline, and theophylline was compared. Results: Cryopreservation impaired sperm parameters dramatically but no significant changes occurred in acrosomal status and apoptosis. Supplementation of papaverine enhanced motility parameters consistently at all exposure intervals, significantly. However, viability was lower at the 60th minute compared to the 30th minute (p=0.019). Papaverine did not alter any acrosomal or apoptotic markers at any time points. All of the compounds compared in this study increased the motility parameters, where theophylline supplementation provided significantly better improvement in total motility compared to papaverine and pentoxifylline. Conclusion: Our results suggest that in vitro papaverine treatment for 30 min adequately improves motility of post-thaw sperm, without leading to acrosome reaction, DNA damage, and viability loss. Theophylline’s potency on increasing the ratio of total motile spermatozoa was found significantly superior than the two tested compounds. Prospective clinical studies with embryo production, pregnancy, and live birth data should be undertaken.