Penetrating capacity of human spermatozoa cool preserved in electrolyte-free solution

To evaluate whether human spermatozoa preserved in electrolyte-free (EF) solution at 4 degrees C possess normal penetrating capacity.The acrosomal status of human spermatozoa cool preserved in EF solution was evaluated before preservation and before and after reinitiation by using chlortetracycline staining. The zona-free hamster egg sperm penetration test was performed using spermatozoa cool preserved in EF solution.The percentages of capacitated and acrosome-reacted spermatozoa cool preserved in EF solution before reinitiation were similar to those of fresh spermatozoa, but they significantly increased after reinitiation. The penetration rate and fertility index of spermatozoa cool preserved in EF solution were comparable to those of fresh spermatozoa (48.3% vs. 50.8% and 1.37 +/- 0.15 vs. 1.29 +/- 0.10, respectively).Human spermatozoa cool preserved in EF solution for one week can possess as much penetrating capacity as fresh spermatozoa.