Evaluation of the meiotic spindle apparatus in metaphase II human oocytes following cytoplasmic donation

Purpose: To determine if the removal of cytoplasm from metaphase II human d onor oocytes damages the meiotic spindle apparatus. Materials and Methods: Cryopreservation of metaphase II human oocytes was p erformed rising a fast-freeze, fast-thaw protocol Upon thaw oocytes were in cubated for 3-4 h and then used for cytoplasmic donation (test oocytes). Oo cytes thawed but not used for donation served as controls. Test and control oocytes were fixed rising a microtubule-stabilizing buffer. Tubulin was lo calized rising antitubulin monoclonal antibody. Chromosomes were identified by counterstaining with DAPI. Results: Forty-four oocytes had cytoplasm removed (test group) while 12 wer e not used for the procedure (controls). Twenty-three oocytes survived the donation procedure. Rates of normal spindle structure for the control and r est groups were 21/23 (91.3%) and 12/12 (100%), respectively Conclusion: The removal of cytoplasm from a metaphase II human donor oocyte does not appear to significantly increase the damage to chromosome alignme nt or to the spindle structure.