[Ultra-rapid cryopreservation of human spermatozoa with different concentrations of sucrose].

ABSTRACT

OBJECTIVE: To explore the feasibility of ultra-rapid freezing of human spermatozoa in the cryogenic vial with different concentrations of sucrose solution. METHODS: We divided 40 normal semen samples prepared with the routine swim-up technique into 6 aliquots, 1 as the control and the other 5 cryopreserved with sucrose solution at the concentrations of 0.15, 0.20, 0.25 and 0.30 mol/L, respectively. After thawing, we determined and compared the motility, progressive motility and plasma membrane integrity of the sperm among the 6 groups. RESULTS: The motility, progressive motility and plasma membrane integrity of the sperm were significantly lower after thawing than before cryopreservation ([96.2 +/- 1.8]%, [93.8 +/- 2.8]% and [99.0 +/- 0.8 ]%) (P<0.05). Post-thawing sperm motility was (55.5 +/- 6.3)% in the 0.20 mol/L sucrose group, significantly higher than in the 0.15, 0.25 and 0.30 mol/L groups ([45.9 +/- 6.6]%, [50.4 +/- 9.4]% and [45.5 +/- 11.2]%) (P<0.05), and it was (53.6 +/- 5.0)% in the conventional freezing group, with no statistically significant difference from the 0.20 and 0.25 mol/L sucrose cryopreservation groups (P> 0.05), but remarkably higher than in the 0.15 and 0.30 mol/L groups (P<0.05). Post-thawing progressive sperm motility exhibited no statistically significant differences between the 0.20 mol/L sucrose and conventional freezing groups ([44.4 +/- 7.4]% vs [42.3 +/- 8.1]%, P>0.05), but markedly higher in both than in the 0.15, 0.25 and 0.30 mol/L sucrose groups ([37.1 +/- 8.3 ]%, [33.1 +/- 9.2]% and [22.0 +/- 9.1]%) (P<0.05). Post-thawing plasma membrane integrity was significantly higher in the 0.20 mol/L sucrose cryopreservation group ( [70.1 +/- 6.9]%) than in either the conventional freezing group ([63.1 +/- 6.8]%) or the 0.15, 0.25 and 0.30 mol/L sucrose groups ([57.7 +/- 8.3]%, [63.5 +/- 10.7]% and [57.8 +/- 12.9]%) (P<0.05). CONCLUSION: As a simple, safe and effective method, ultra-rapid freezing with sucrose solution at the final concentration of 0.20 mol/L can be used for the cryopreservation of human spermatozoa.