Marked improvement of fertility of cryopreserved C57BL/6J mouse sperm by depletion of Ca2+ in medium.
Cryopreservation of mouse sperm is useful for maintaining various strains. However, fertility generally decreases after freezing. In particular, the fertility of cryopreserved C57BL/6J sperm is very low. To improve the fertility of frozen sperm, we examined the efficiencies of various media used for sperm preincubation (SP) and in vitro fertilization (IVF) in frozen C57BL/6J sperm. In this study, SP medium was examined for efficiency of fertility with respect to content, especially calcium (Ca(2+)), phosphate (PO(4)(3-)) and lactate. In all media containing no Ca(2+), including medium lacking Ca(2+), lacking Ca(2+) and PO(4)(3-), lacking Ca(2+) and lactate and lacking Ca(2+), PO(4)(3-) and lactate, high IVF rates were obtained (79, 69, 76 and 71%, respectively). On the other hand, the rates for media containing Ca(2+) were significantly lower (30-38%, P<0.05). After transfer, 41-50% of newborns were obtained in all media containing no Ca(2+). In conclusion, preincubation of thawed sperm in medium containing no Ca(2+) markedly improved the fertility of cryopreserved C57BL/6J sperm. These results indicate that the present method of IVF using medium with no Ca(2+) is practical for use in cryopreserved C57BL/6J sperm.
Mitsubishi Kagaku Institute of Life Sciences, Tokyo, Japan. rmigishima@ivfnamba.com
Rika
R
Suzuki-Migishima
Toshiaki
T
Hino
Miho
M
Takabe
Kanako
K
Oda
Fujio
F
Migishima
Yoshiharu
Y
Morimoto
Minesuke
M
Yokoyama
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015925:Cryopreservation / Q000295:instrumentation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D003470:Culture Media / Q000494:pharmacology*; D005260:Female; D005298:Fertility; D005307:Fertilization in Vitro; D007773:Lactates / Q000378:metabolism; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010710:Phosphates / Q000378:metabolism; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism*
D003451:Cryoprotective Agents; D003470:Culture Media; D007773:Lactates; D010710:Phosphates; D002118:Calcium