Cryopreservation of murine spermatozoa

Cryopreservation of mouse sperm provides an eco-nomic option for preserving the large number ofmouse strains now being generated by transgenic and targeted mutation methodologies. The ability of a spermato-zoan cell to survive cryobiological preservation depends on general biophysical constraints that apply to all cells, such as the avoidance or minimization of the formation of intracellular ice during cooling. This action is typically achieved by use of cryoprotectant substances and by controlled, slow rates of cooling. Superimposed on those general constraints may be special characteristics of mouse spermatozoa, such as more narrow, osmotically driven volume tolerance limits and the fact that relatively successful freezing can be obtained with-out the use of a permeating cryoprotective agent. The lack of important information regarding sperm cells ' fundamental cryobiological properties, including their osmotic and mem