Effect of caffeine treatment before vitrification on MPF and MAPK activity and spontaneous parthenogenetic activation of in vitro matured ovine oocytes.

BACKGROUND: Molecules that stabilize protein kinases may be useful in overcoming the deleterious effects of cryopreservation. OBJECTIVE: To evaluate the effect of caffeine treatment before vitrification of in vitro matured ovine oocytes on the activity of MPF and MAPK as well as the spontaneous parthenogenetic activation after 24 h culture. MATERIALS AND METHODS: Oocytes obtained from slaughterhouse sheep ovaries were in vitro matured for 21 h, incubated for 3 h with or without caffeine and then vitrified. After warming, oocytes were processed for the analysis of chromatin configuration and the evaluation of spontaneous parthenogenetic activation (24 h in vitro culture). Fresh in vitro matured oocytes were used as control. RESULTS: Caffeine treatment before vitrification maintained the MPF activity at a level similar to that of fresh oocytes, and reduced the spontaneous parthenogenetic activation in comparison with oocytes that were not-treated with caffeine. CONCLUSION: Caffeine treatment prolongs the meiotic arrest of vitrified MII oocytes, likely via its action of stabilizing the MPF level.