RESUMEN
Objective@#To investigate the application value of the frozen-thawed round spermatids of the mouse in in vitro fertilization (IVF).@*METHODS@#Haploid spermatids of the mouse obtained in vitro were divided into a frozen-thawed and a fresh group and oocytes were collected from 6－8 weeks old female mice. After diamidino-phenyl-indole (DAPI) staining, the oocytes were subjected to intracytoplasmic round spermatid injection (ROSI), 259 in the frozen-thawed and 238 in the fresh group. Comparisons were made between the two groups in the capacities of fertilization and embryonic development.@*RESULTS@#The survival rate of the frozen-thawed haploid spermatids was (75.9 ± 2.3) %. No statistically significant differences were observed between the frozen-thawed and fresh groups after ROSI in the rates of fertilization (51.9 vs 55.7%, P >0.05), 2-cell embryos (51.0 vs 62.2%, P >0.05), 4－8-cell embryos (41.8 vs 42.9%, P >0.05), or morula-blastocysts (12.2 vs 21.4%, P >0.05).@*CONCLUSIONS@#Frozen-thawed round spermatids of the mouse are similar to fresh ones in their capacities of fertilization and embryonic development.