QUALITY OF FROZEN-THAWED TESTICULAR SPERM AND ITS PRECLINICAL USE FORINTRACYTOPLASMIC SPERM INJECTION INTO IN VITRO-MATURED GERMINAL-VESICLE STAGE OOCYTES

Objective: To study the effects of cryopreservation on the quality of human testicular spermatozoa and the efficiency of intracytoplasmic sp erm injection (ICSI) with frozen-thawed testicular sperm into metaphas e II oocytes in vitro-matured from the germinal-vesicle stage oocyte. Design: Preclinical freezing study on supernumarary testicular spermat ozoa after ICSI. Setting: Tertiary IVF center coupled with an institut ional research environment. Patient(s): Twenty-nine patients undergoin g excisional testicular biopsy far ICSI. Intervention(s): Isolated tes ticular spermatozoa were cryopreserved and thawed; frozen-thawed motil e testicular spermatozoa were microinjected. Main Outcome Measure(s): Prefreezing and post-thawing motility and viability, survival rate, fe rtilization rate, cleavage fate, and embryo quality after ICSI. Result (s): Mean percentage motility decreased from 21% before freezing to 6% after thawing. Vitality was impaired to a similar extent, decreasing from 68% to 22% (32% recovery rate). Injection of frozen-thawed testic ular spermatozoa into in vitro-matured oocytes resulted in a fertiliza tion rate of 50.9%. Cleavage rate tvas severly impaired. Half of the f ertilized oocytes became ar rested in the one-cell stage. Conclusion(s ): Despite the low quality of the fresh testicular spermatozoa, a high percentage of prepared testicular sperm fractions showed survival and motility after the freezing and thawing profess. Injection of frozen- thawed testicular sperm into matured oocytes resulted in fertilization rates comparable with these with fresh testicular sperm, but cleavage rates were severely impaired, which might be due to source of oocytes used for ICSI.