A combined treatment with ethanol and 6-dimethylaminopurine is effective for the activation and further embryonic development of oocytes from Sprague-Dawley and Wistar rats

Role of AMPK throughout meiotic maturation in the mouse oocyte: evidence for promotion of polar body formation and suppression of premature activation

This study was conducted to assess the role of AMPK in regulating meiosis in mouse oocytes from the germinal vesicle stage to metaphase II. Exposure of mouse cumulus cell-enclosed oocytes (CEO) and denuded oocytes (DO) during spontaneous maturation in vitro to AMPK-activating agents resulted in augmentation of the rate and frequency of polar body formation. Inhibitors of AMPK had an opposite, inhibitory effect. In addition, the AMPK inhibitor, compound C (Cmpd C) increased the frequency of oocyte activation. The stimulatory action of the AMPK-activating agent, AICAR, and the inhibitory action of Cmpd C were diminished if exposure was delayed, indicating an early action of AMPK on polar body formation. The frequency of spontaneous and Cmpd C-induced activation in CEO was reduced as the period of hormonal priming was increased, and AMPK stimulation eliminated the activation response. Immunostaining of oocytes with antibody to active AMPK revealed an association of active kinase with chromatin, spindle poles, and midbody during maturation. Immunolocalization of the α1 catalytic subunit of AMPK showed an association with condensed chromatin and the meiotic spindle but not in the spindle poles or midbody; α2 stained only diffusely throughout the oocyte. These data suggest that AMPK is involved in a regulatory capacity throughout maturation and helps promote the completion of meiosis while suppressing premature activation.

Techniques for in vitro and in vivo fertilization in the rat

Although in vitro and in vivo fertilization are powerful tools for restoring conserved sperm as well as stocked males in the rat, the techniques have progressively gained importance. However, the techniques are not used extensively for efficient production of rat offspring, because the techniques require a great deal of skill. This chapter describes the protocols for in vitro and in vivo fertilization in the rat. Namely, sperm collection, sperm cryopreservation, pre-incubation of sperm, and insemination (co-culture with sperm and oocytes) for in vitro fertilization and intrauterine insemination for in vivo fertilization with fresh or frozen/thawed spermatozoa are provided.