Superovulation strategies for 6 commonly used mouse strains.

We examined different weight ranges and hormone dosages to determine superovulation protocols for 6 mouse strains commonly used in genetic engineering: C57BL/6NHsd, B6(Cg)-Tyr(c-2J)/J, B6D2F1/Hsd, FVB/NHsd, BALB/cAnNCr, and Crl:CD1(ICR). Mice from each strain were divided into groups based on weight roughly corresponding to those of 3-, 4-, 5-, and 6-wk-old mice. Mice were treated with 5 IU pregnant mare serum gonadotropin (PMSG) and 5 IU human chorionic gonadotropin (HCG). The weights of mice that produced maximal numbers of oocytes in response to these doses were 14.2 g or less for C57BL/6NHsd, 13.7 g or less for B6(Cg)-Tyr(c-2J)/J, 6.0 to 9.9 g for B6D2F1/Hsd, 14.5 to 16.4 g for FVB/NHsd, 14.8 g or less for BALB/cAnNCr, and 23.5 g or more for Crl:CD1(ICR). We then compared PMSG dosages of 5 and 2.5 IU per mouse and determined whether 2 doses of PMSG (5 or 2.5 IU, depending on prior results) administered 1 wk apart, followed by the standard HCG injection, would produce more oocytes when compared to a single dose of PMSG. FVB, B6D2F1, BALB/c, and CD1 mice responded best to a single dose of 5 IU of each hormone, whereas B6(Cg)-Tyr (c-2J)/J mice produced more oocytes after 2.5 IU PMSG. Although C57BL/6 mice given the standard dose produced good numbers of oocytes, the number was higher after 2 doses of PMSG at 5 IU per dose. We conclude that response to superovulation can be optimized based on mouse strain, weight, and the dose and timing of hormone injection. Copyright 2011 by the American Association for Laboratory Animal Science