["Successful cryopreservation of rat spermatozoa from various strains still remains a challenge. The objective of this study was to determine if combinations of OptiPrep™ (iodixanol) and adenosine 5'-triphosphate (ATP) can improve rat sperm function during the cryopreservation procedure.", 'Epididymal rat spermatozoa were frozen under different OptiPrep™ concentrations (0, 1, 2, 3 or 4\xa0%) and were diluted with media supplemented with or without 2\xa0mM ATP after thawing. Post-thaw sperm motility, acrosomal membrane integrity (AMI) and mitochondrial membrane potential (MMP) were then evaluated. In addition, the effect of different OptiPrep™ concentrations on fresh and cooled rat spermatozoa was tested via motility.', 'There was no effect of OptiPrep™ on motility of fresh and cooled spermatozoa. The supplementation of 1 and 2\xa0% OptiPrep™ increased motility of frozen spermatozoa at 10\xa0min after thawing, while it did not improve motility of spermatozoa at 3\xa0h after thawing in the absence of ATP. During incubation of thawed spermatozoa, the ATP addition protected time-dependent decrease in motility after thawing in OptiPrep™-treated samples. OptiPrep™ had no effect on AMI and MMP in frozen-thawed spermatozoa but combinations of OptiPrep™ and ATP improved MMP in frozen-thawed spermatozoa.'] Does post-thaw ATP supplementation enhance cryoprotective effect of iodixanol in rat spermatozoa?