Rat oocytes fertilized in modified rat 1-cell embryo culture medium containing a high sodium chloride concentration and bovine serum albumin maintain developmental ability to the blastocyst stage.
A suitable chemically defined culture medium for 1-cell rat embryos (mR1ECM) was modified to obtain sperm penetration, and the developmental competence of oocytes fertilized in the medium was compared to that of oocytes fertilized in a traditional medium, modified Krebs-Ringer bicarbonate medium (mKRB). Sperm penetration was not observed when polyvinyl alcohol was replaced with BSA in mR1ECM (mR1ECM-BSA); the incidence was improved only when the osmolarity in mR1ECM-BSA was increased to that in mKRB (310 mOsm) by addition of NaCl. The proportion of oocytes penetrated in mR1ECM-BSA with NaCl increased (71.6 +/- 6.9%), which was not different compared to that in mKRB (76.7 +/- 13.7%). High incidences of sperm penetration (88.8 +/- 4.1% to 93.1 +/- 5.1%) were also observed when NaCl concentration in mR1ECM-BSA was increased from 76.7 mM to 100-130 mM. The incidence of embryos developing to the morula and blastocyst stages was higher when fertilized in mR1ECM-BSA containing 110-130 mM NaCl (91-94%) than in mKRB (70%). A total of 5 offspring were obtained after transfer of the morulae and blastocysts (69 embryos/7 females). These results demonstrate that a high developmental ability of rat embryos to the blastocyst stage is attained when the embryos have been fertilized in mR1ECM-BSA containing 110-130 mM NaCl and then cultured in mR1ECM.
Oh
S H
SH
Department of Animal Science and Technology, Okayama University, Tsushima-naka, Okayama 700-8530 Japan.
Miyoshi
K
K
Funahashi
H
H
D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000502:physiology*; D003470:Culture Media; D005314:Embryonic and Fetal Development; D005260:Female; D005307:Fertilization in Vitro; D008297:Male; D009865:Oocytes / Q000502:physiology*; D009994:Osmolar Concentration; D010710:Phosphates / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D012710:Serum Albumin, Bovine / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*; D019354:Sodium Lactate / Q000494:pharmacology; D013084:Sperm-Ovum Interactions / Q000502:physiology
D003470:Culture Media; D010710:Phosphates; D012710:Serum Albumin, Bovine; D012965:Sodium Chloride; D019354:Sodium Lactate