Short-term preservation of mouse oocytes at 5 degrees C

The temporary preservation of oocytes without freezing would be useful for some experiments. ICR mouse oocytes were kept in a preservation medium unde r mineral oil for 1, 2, 3, 4 or 7 days at 5 degreesC, and 1 or 2 days at 37 degreesC. In vitro fertilization was attempted on oocytes rinsed with TYH medium after preservation. More than 70% of morphologically normal oocytes were recovered from each preservation group. Fertilization rates of oocytes preserved for 1, 2, 3, 4 or 7 days at 5 degreesC were 69.9, 66.5, 45.3, 26 .7 and 8.8% respectively. Fertilization rates of oocytes preserved for 1 or 2 days at 37 degreesC were 9.6 and 1.6%, respectively. Preservation of ooc ytes at 5 degreesC has some capability as a method of short-term storage wi thout freezing.