Objective: To evaluate the safety of intracytoplasmic sperm injection (ICSI) in the mouse model.
Methods: We simulated clinical ICSI technology and comprehensively evaluated it by parthenogenetic activation, immunofluorescence, embryo transplantation, examination of early implantation, and measurement of the crown-rump length (CRL).
Results: ICSI significantly reduced the ability of preimplantation embryo development of the mouse, especially after the 8-cell stage (P < 0.01). The fluorescence of H3K9 dimethylation was abnormal at the male pronuclei of the embryos derived from ICSI. Further examination of the development of the transferred ICSI embryos indicated no significant difference in the rate of early implantation at E5. 5 days as compared with normal fertilization (P = 0.6), but the percentage of "normal embryos" was decreased significantly at E9.5 days (P < 0.01). Obvious growth retardation phenotype was observed even in the normal ICSI embryos at E9.5 days.
Conclusion: ICSI might result in growth retardation of embryos by affecting H3K9 dimethylation in the male pronuclei.