In vitro fertilization with cryopreserved inbred mouse sperm

Sperm from C57BL/6J, DBA/2J, BALB/cJ, 129S3/SvImJ, and FVB/NJ inbred mice w ere cryopreserved in 3% skim milk/18% raffinose cryoprotectant solution. Th e post-thaw sperm from ail strains were evaluated for their viability and f ertility by comparing them against B6D2F1 sperm used as a control. The prot ocol used for freezing mouse sperm was effective in different strains, beca use the motility was decreased by 50% after cryopreservation similar to oth er mammalian sperm. However, the progressive motility and the fertility of each inbred strain were affected differently. The C57BL/6J, BALB/cJ, and 12 9S3/SvImJ strains were the most affected; their fertility (two-cell cleavag e) decreased from 70%, 34%, and 84% when using freshly collected sperm to 6 %, 12%, and 6% when using frozen/thawed sperm, respectively. Live newborns derived from frozen/thawed sperm were obtained from all strains in the stud y. These results corroborate the genetic variation among strains with regar d to fertility and susceptibility to cryopreservation.