Effect of Quercetin-loaded liposomes on induced oxidative stress in human spermatozoa

• Q loaded in liposomes shows lower toxicity than Q for sperm motility and viability.
• Q loaded in liposomes may damage sperm DNA.
• Q loaded in liposomes shows less antioxidant activity vs Q on sperm induced LPO.

A strategy to circumvent the poor polyphenols bioavailability is to load these compounds into liposomes. We evaluated the in vitro effects of quercetin (Q) and Q-loaded liposomes (QLL, 30, 50, 100 μM) on motility, viability and chromatin integrity of swim-up selected human sperm. Antioxidant power was assayed against tert-butylhydroperoxide induced lipid peroxidation (LPO) using C11-BODIPY581/591 fluorescent probe and transmission electron microscopy. QLL showed decreased toxicity for sperm motility and viability and increased DNA damage compared to Q. The percentage of sperm with fluorescence, marker of LPO, was decreased in samples incubated with Q vs QLL (P < 0.001). The ultrastructure of acrosomes and membranes was preserved with Q 30/100 μM, whereas QLL did not prevent membrane injury.Q alone appeared more effective than Q incorporated into liposomes; however liposomes could be considered as carriers that may convey different compounds inside sperm; they may therefore represent a field of research rich of many applications.