320 effects of different activation regimens on pronuclear formation and pre-implantation developmental competence of in vitro-matured XXXX oocytes after intracytoplasmic sperm injection.

@entity1 @entity20119 @entity1880 @entity167 @entity11007 @entity515 @entity1068 @entity1360 @entity291
Intracytoplasmic sperm injection (ICSI) is an assisted reproductive technique that has been used with considerable success in @entity1 ; however, in the @entity291 species the efficiency of this technique is far from optimal. The objective of the present study was to evaluate the effect of 4 chemical activation treatments, @entity20119 (DMAP), @entity1880 (CHX), @entity11007 (ANY), and @entity1068 ( @entity167 ) on the pronuclear formation and embryo development of @entity291 embryos generated by ICSI. Cumulus-oocyte complexes were aspirated from abattoir ovaries, selected, and matured in 400-  L drops of standard TCM-199 maturation medium for 22h at 38.5  C and 5% @entity515 . The ICSI was performed by a standard procedure. Injected oocytes were randomly distributed and activated by 5  M @entity1360 for 5min (Io) followed by i) 5  gmL(-1) CHX for 5h (Io/CHX), ii) 3h window followed by a second Io treatment plus 1.9mM DMAP for 4h (2Io/DMAP), iii) 1  gmL(-1) ANY for 5h (Io/ANY), and iv) 3h window followed by 7% @entity1068 (Io/ @entity167 ). Embryos were cultured in 50-  L drops of KSOM medium under mineral oil at 38.5  C and 5% @entity515 , 5% O2, and 90% N2. Cleavage was recorded at 72h and blastocyst rate at 192h. Pronuclear formation analysis was carried out at 18 hpa with Hoechst staining. An oocyte was considered fertilized when 2 polar bodies and 1 female and 1 male pronucleus (or a decondensed sperm head) could be observed. The data were transformed to arcsine, analysed by ANOVA, and means were compared using Tukey's test with Statgraphics Plus 2 Software. Results with a total of 431 injected oocytes (114, 104, 101, and 112 for DMAP, CHX, ANY, and @entity167 , respectively) showed differences in cleavage (P<0.01) in DMAP, CHX, and ANY treatments (86, 72, and 78%, respectively), relative to @entity167 (12%). Similarly, the rate of blastocysts/injected oocyte at 192h was higher with DMAP, CHX, and ANY (41, 20, and 32%, respectively), relative to @entity167 (4%). Sham-injected oocytes showed cleavage and blastocyst rates of 67, 43, 68, and 12% and 32, 11, 19, and 5%, for DMAP, CHX, ANY, and @entity167 , respectively. Despite the higher developmental rate observed with DMAP, pronuclear formation assessment revealed that fertilization rate was higher in CHX (87%) and ANY (75%) treatments relative to DMAP (35%). In conclusion, the results of the present study show that activation of @entity291 oocytes after ICSI is more efficient with DMAP and ANY, compared with CHX and @entity167 .
