Resveratrol and male infertility: a systematic review of the literature.

INTRODUCTION

The aim of this study is to provide an updated and comprehensive systematic review on the effects of resveratrol (RSV) in male infertility and sperm preservation.

EVIDENCE ACQUISITION: This systematic review followed the MOOSE guidelines for Meta-analyses and Systematic Reviews of Observational Studies and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P). Only original articles evaluating the effect of RSV on human spermatozoa in vivo or in vitro were included.

EVIDENCE SYNTHESIS: Of the 1806 abstracts evaluated for eligibility, only 12 studies were included in the qualitative synthesis, of which three were prospective in-vivo studies and nine were in-vitro studies. Out of three human studies on RSV, only two studies administered RSV alone, one of them reported a positive impact and the other reported no significant impact on semen parameters. Overall, the in-vitro studies have reported the ability of RSV to protect spermatozoa against damage due to freeze-thaw cycles during cryopreservation. Other in-vitro studies have reported positive effects of RSV in fresh samples and protective effects in cell lines.

CONCLUSIONS

Available in-vivo studies are controversial with regard to the effect of RSV in improving semen parameters. In-vitro studies support the use of RSV before sperm cryopreservation. Further well-designed prospective studies on large sample sizes are needed to fully understand the role of RSV in the treatment of male infertility in vivo.