PARTHENOGENETIC ACTIVATION OF HUMAN OOCYTES FOLLOWING CRYOPRESERVATION USING 1,2-PROPANEDIOL

Fresh and aged human oocytes were cryopreserved using 1,2-propanediol (PROH). After thawing, the oocytes were cultured for 20 h and examined for parthenogenetic activation using light microscopy and an ultravio let DNA stain, Control fresh or aged oocytes and oocytes exposed to PR OH without cryopreservation were also examined for activation, No cont rol oocytes were observed to activate spontaneously (n = 43) and parth enogenetic activation was not induced by exposure to PROH alone (n = 2 6), In both fresh and aged cryopreserved oocytes, 27 and 29% of the oo cytes respectively were activated, and these proportions were signific antly elevated compared with the controls (P < 0.01), Although a simil ar rate of activation was observed for the cryopreserved fresh and age d oocytes, the form of parthenogenetic activation varied between these two types of oocyte, A single pronucleus was observed in 18% of the f resh and 5% of the aged cryopreserved oocytes. In contrast, the presen ce of two or more pronuclei was observed in 0% of the fresh and 19% of the aged cryopreserved oocytes.