BRC Current Technology August 2012

5. Superovulation with anti-inhibin serum

Toward efficient preservation and use of wild-derived strains



  Ovulation in mammals is hormonally regulated by the pituitary-gonadal axis. Normally, one to 10
mature oocytes are ovulated from the ovaries, depending on the species. To make the best use of
female animals for the studies of reproductive biology and developmental biology, they are usually
administered with hormones to ovulate excessive numbers of oocytes; i.e., the so-called
superovulation treatment. For superovulation of laboratory mice, the combination of equine chorionic
gonadotropin (eCG) and human chorionic gonadotropin (hCG) generally works well because eCG has
an FSH-like activity and stimulates folliculogenesis in mice. However, many wild-derived strains
poorly respond to this treatment by unknown causes. Recently, we have found that treatment with
anti-inhibin serum instead of eCG was effective for superovulation of wild-derived strains. Since
inhibin suppresses FSH secretion from the pituitary, the anti-inhibin treatment is expected to
increase the endogenous FSH secretion. In MSM/Ms and JF1/Ms strains, most popular wild-derived
strains at our center, this treatment resulted in five fold increase in the number of ovulated oocytes
(from about 5 to 25). These oocytes developed normally after in vitro fertilization and were safely
cryopreserved at the 2-cell stage. At our center, many of other wild-derived strains have been
successfully cryopreserved by this technique. In addition, we have improved the embryo transfer
technique for efficient production of wild-derived mice. Maintenance of wild-derived strain has been
one of the biggest challenges at our center. Now they can be safely preserved in LN2 and efficiently
distributed to researchers by request. They would provide unique experimental animal models for the
future biomedical researches.
(Bioresource Engineering Division, RIKEN BRC)

Reference:Hasegwa et al., Biol. Reprod. 86(5):167, 1-7. Print 2012

Comment in: Ward MA, Biol. Reprod. 86(5):168, 1-2. Print 2012



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