The addition of fructose or sodium citrate does not improve recovery rates of cryopreserved human spermatozoa.

OBJECTIVE

To evaluate the effects of the addition of sodium citrate and/or fructose to medium containing egg yolk, glycerol and TEST buffer (TES(N-tris[hydroxymethyl] methyl-2-aminoethanesulfonic acid) plus Tris (hydroxymethyl)-aminomethane) on human sperm cryopreservation.

DESIGN

Sperm cryopreservation in three cryoprotective media, followed by thawing 3 weeks or 3 months later.

SETTING

University outpatient clinic.

MATERIAL AND METHODS

Twenty-two semen samples from fertile men were evaluated before and after freezing for 3 weeks or 3 months in three different cryoprotective media consisting of a stock solution (TEST-YOLK) to which 20% sodium citrate was added plus 2% fructose (TESTC I) or to which 20% sodium citrate, but no fructose, was added (TESTC-II).I MAIN OUTCOME MEASURES: Measurements of quantitative sperm motility, progressive motility, vitality and recovery rates before and after freezing.

RESULTS

Before freezing, the addition of the different media increased sperm progressive motility but did not change quantitative motility or vitality. Sample freezing reduced all the above variables both after 3 weeks and after 3 months, with no difference between the two freezing times. Semen analysis two hours after thawing showed a significant fall in both motility and vitality when compared with samples analyzed immediately after thawing. No significant differences in recovery rates were observed between media or within the same medium when the two freezing times (3 weeks and 3 months) were compared.

CONCLUSION

The addition of sodium citrate and/or fructose to the cryoprotective medium does not improve sperm motility or vitality after freezing.