Preservation of human spermatozoa in a simple medium

The objective of this study was to estimate the best conditions for sperm preservation in a simple medium and to examine the changes in sperm morphology and vitality due to preservation.Swim-up technique was carried out using KSOMaa medium (potassium simplex optimized medium with amino acid) then, such sperms were preserved without/with supplementation of BSA to the medium in two different osmolarities (271 and 800 mOsmal). Sperms were preserved for 2 weeks in three different temperatures (37 °C, 4 °C and −20 °C). Our results demonstrated that: (1) KSOMaa medium is a good medium to obtain progressive motile sperms with a good morphology. (2) The best conditions for preserving human spermatozoa were 800 mOsmol KSOM-BSA and a holding temperature of −20 °C. (3) Light and electron microscopy showed that cryodamage has been induced in some human spermatozoa due to preservation. Collectively, our data indicate that this new simple procedure could be the method of choice for selecting motile and morphologically normal spermatozoa. This new preservation method may help in vitro fertilization centers but should be tested to check the embryonic development after intracytoplasmic sperm injection.