A new method for cryopreservation of mouse spermatozoa.

A new method for the cryopreservation of mouse spermatozoa was developed using a modified egg-yolk TES-Tris diluent containing 0.1% sodium lauryl sulfate and 1.25% (v/v) glycerol (mouse sperm cryoprotectant, MSC). Epididymal spermatozoa collected from 10-week-old CBA males were frozen at a rate of 5 degrees C min-1 to 4 degrees C and 50 degrees C min-1 to -70 degrees C using a programmable cell freezer. A percentage of the spermatozoa (25%) regained motility after thawing. In vitro fertilization with frozen-thawed spermatozoa resulted in 50% of oocytes developing to the two-cell stage. These two-cell embryos were placed in the oviducts of pseudopregnant recipients (C57BL/CBA) and 16% developed to be viable fetuses, or in the oviducts of pregnant recipients (MF1) and 17% developed to live offspring.