Chromosomal analysis of mouse spermatozoa following physical and chemical treatments that are effective in inactivating HIV

Human immunodeficiency virus (HIV) can be inactivated by heating at 56 degrees C for 30 min, treating with 50% ethanol at room temperature for 10 min, or treating with 2% sodium hypochlorite solution (NaClO) at room temperature for 60 min. Using a mouse model, we evaluated the risk of generating chromosome damage in spermatozoa following these treatments. The spermatozoa were all dead after the treatments. Although 41.3% of oocytes injected with ethanol-treated spermatozoa successfully activated, none of the oocytes injected with heated or NaClO-treated spermatozoa activated. When artificial stimulation with strontium was used, the fertilization of oocytes with heated or ethanol-treated spermatozoa was completely rescued. Sperm nuclei treated with NaClO neither decondensed nor developed to a male pronucleus. The incidences of structural chromosome aberrations in 1-cell zygotes derived from the heated spermatozoa (45.6%) and ethanol-treated spermatozoa (91.2%) were significantly higher than those in the matched controls (5.5% and 10.5%, respectively). Further study is needed to develop a methodology for the protection of spermatozoa against chromosome damage or the separation of damaged spermatozoa before intracytoplasmic sperm injection.