CRYOPRESERVATION OF MOUSE SPERMATOZOA FROM INBRED AND F1-HYBRID STRAINS

Mouse epididymal spermatozoa from inbred(BALB/c, C3H/He, C57BL/6N, CBA /JN and DBA/2N) and F1 hybrid (B6C3F1, BDF1 and CDF1) strains suspende d in cryopreservation solution (18% raffinose and 3% skim milk in dist illed water) were frozen and stored at -196-degrees-C . After thawing at room temperature, sperm motility and fertilizing ability were exami ned. Spermatozoa from all of the strains were successfully frozen, alt hough the motility and the fertilization rates of frozen-thawed sperma tozoa (the proportions of the fresh oocytes from Jcl : ICR strain whic h developed to pronuclear oocytes and 2-cell embryos after inseminatio n by frozen-thawed spermatozoa) varied among strains (motility : 23% f or C57BL/6N to 62% for DBA/2N ; fertilization rates : 26% for C57BL/6N to 89% for DBA/2N). Nearly all 2-cell embryos fertilized by frozen-th awed spermatozoa were transferred to the oviducts of pseudopregnant re cepients and 35-62% of 2-cell embryos developed into normal young.