ACTA ENDOCRINOLOGICA (BUC)

Objective. The aim of this study was to evaluate the impact of sperm DNA fragmentation (SDF) on fertilization rate, and sperm nuclear decondensation after intracytoplasmic injection of sperm (ICSI) into cumulus-free germinal vesicle (GV) oocytes from stimulated cycles. Methods and study design. After the retrieval of oocytes, the GV oocytes were cultured for 24 h. Oocytes that liberated polar bodies were injected with processed semen, and were used to evaluate SDF level. Based on SDF, the data were categorized into two groups. Group I in which SDF≤ 30% and group II in which SDF > 30%. Fertilization (presence of two pronuclei) was checked 16-19 h after ICSI. Unfertilized oocytes were stained by Hoechst 33258 and examined to evaluate the undecondensed sperm head in oocyte. The rates of maturation, fertilization in fertilized IVM oocytes and the percentage of undecondensed sperm in the unfertilized oocytes were assessed according to SDF. Results. Out of 146 GV oocytes that were subjected to IVM, 101 (69 %) developed to metaphase II. The fertilization rate of IVM oocytes in group II was significantly lower than that in group I (P < 0.05). Moreover, group I, had 25 % of their unfertilized oocytes containing condensed sperm, while group II had a significantly higher number (53 %) of unfertilized oocytes containing condensed sperm (P < 0.05). Conclusion. SDF had a negative effect on the rate of fertilization in matured in vitro GV oocytes and could lead to an increase in the percentage of undecondensed sperm in IVM oocytes from stimulated cycles.