C-35: Preservation of mammalian sperm by freeze-drying

Abstract

Stable conservation of genetic resources is important in various research fields. Sperm preservation is a valuable method for bio-banking of mammalian genetic resources. Freeze-drying is a useful technique for storing biological materials as samples can be preserved for a long-term in a refrigerator (4 °C). Freeze-drying sperm has been studied as a new, simple preservation method in various mammals. It is an effective method preservation as it has been reported that offspring could be obtained from mouse and rat sperm preserved long term at 4 °C after freeze-drying using a simple solution containing 10 mM Tris and 1 mM EDTA adjusted pH to 8.0 (TE buffer) (Kaneko T., Cryobiology 64, 211–214, 2012; Kaneko T., PLoS One 7, e35043, 2012). Freeze-drying sperm results in lower costs and increased safety, as specialized cryoprotectants and a constant supply of liquid nitrogen is not required. A further advantage is that freeze-dried sperm can be temporarily stored at room temperature. Freeze-drying is possible to transport sperm oversea at ambient temperature that requires neither liquid nitrogen nor dry ice. Furthermore, freeze-dried valuable samples can be also protected safety even at ambient temperature in the event of unexpected power failure and disaster such as earthquakes and typhoons. At the present, freeze-drying sperm has been applied to a “Freeze-drying Zoo” for conservation of wild endangered animals ( http://www.anim.med.kyoto-u.ac.jp/reproduction/home.aspx ).