Effects of cold storage on plasma membrane, DNA integrity and fertilizing ability of feline testicular spermatozoa

This study examined the effects of cold storage on plasma membrane, DNA integrity, and fertilizing ability of domestic cat spermatozoa. Intact cat testes were stored at 4 °C in Dulbecco's phosphate buffered saline (DPBS) for 7 days. Membrane integrity (experiment 1) and DNA integrity (experiment 2) of extracted spermatozoa were assessed over time during storage. Testicular spermatozoa were also tested for their fertilizing ability via intracytoplasmic sperm injection (ICSI) in term of gamete activation and early embryonic development at 18 h (experiment 3).The membrane integrity of testicular spermatozoa was well preserved in DPBS for 4 days compared to non-preserved control (Day 0) (P < 0.05). The incidence of testicular sperm DNA fragmentation was <1% after 7 days of cold storage and was not significantly affected by the duration of cold storage (P > 0.05). Finally, testicular spermatozoa could form pronuclei and sustain embryo development following ICSI regardless of the storage time (P > 0.05). In conclusion, cat testicular spermatozoa can be preserved at 4 °C for up to 7 days without severely compromising of plasma membrane and DNA integrity while retaining a normal fertilizing ability.