IMPROVING THE INTRACYTOPLASMIC SPERM INJECTION TECHNIQUE BY TRANSMEMBRANE ELECTRIC-POTENTIAL MONITORING

Objective: To evaluate electrophysiologic techniques for transmembrane potential measurement during intracytoplasmic sperm injection (ICSI). Design: Mature mouse oocytes were subjected to intracellular measurem ents of membrane potential using conventional techniques and modificat ions of the techniques for use with sham ICSI. During the procedure, t he actual penetration of the membrane was determined subjectively or o bjectively with or without monitoring membrane potential. Setting: Aca demic medical center. Animal(s): Mouse. Intervention(s): Measurement o f oocyte membrane potential (Sham ICSI). Main Outcome Measure(s): Dete ctability of transmembrane potential using different electrodes and co mparison of subjective and objective determination of membrane penetra tion. Result(s): Measurement of the membrane potential with the same g lass pipettes used in ICSI means compromise between signal amplitude a nd compatibility with the conventional ICSI setup. Signal quality is r elated inversely to the diameter of the injection pipette, and its amp litude decreases as the concentrated electrode filling solution is rep laced by physiologic solutions used in ICSI. When successful membrane penetration is suspected by visualization, measuring the potential at the tip of the injection pipette often proves otherwise. Conversely, w hen membrane penetration is confirmed by detection of transmembrane po tential, the procedure may appear subjectively unsuccessful. Conclusio n(s): Monitoring of transmembrane potential can be done successfully i n conjunction with standard ICSI and has several potential application s. (C) 1997 by American Society for Reproductive Medicine.