Effects of temperature on sperm motion characteristics and reactive oxygen species.

OBJECTIVE To evaluate the effect of temperature on sperm motility, sperm motion characteristics, and production of reactive oxygen species (ROS) in semen. METHODS We collected semen samples from 12 infertile patients and 12 healthy donors and divided each sample into four aliquots just after liquefaction. One aliquot was analyzed immediately after liquefaction and the remaining three were analyzed after one hour of incubation at 4 degrees C, 25 degrees C, and 37 degrees C. Sperm motility and motion characteristics were measured by computer-assisted sperm analysis (CASA). Levels of ROS were determined in washed sperm suspensions using a chemiluminescence assay and results were expressed as x10(6) counted photons per minute (cpm)/20 million sperm/mL. RESULTS Motility, curvilinear velocity, straight-line velocity, average path velocity, and amplitude of lateral head displacement decreased significantly from baseline values in both the patients and donors after incubation at 4 degrees C. Percentage motility was highest and ROS levels were lowest in the samples that were incubated at 37 degrees C. CONCLUSION Based on our results, we suggest that semen samples be stored at 37 degrees C after collection and during transportation and processing.