Recovery of motile sperm using the osmolality-gradient technique

Spermatozoa recovered by IxaPrep gradient have improved longevity and better motion characteristics than those by Percoll gradient

To compare the effectiveness of various sperm preparation methods, we examined sperm concentration, percentage of progressive motility, recovery rate, and various motion characteristics in 32 semen samples after Percoll and IxaPrep preparations. Except for sperm concentration, which was much higher after IxaPrep preparation, no statistical differences existed between these two methods in terms of motile sperm concentration (MSC), recovery rate, mean curvilinear velocity (VCL), mean straight-line velocity (VSL) and mean amplitude of lateral head displacement (ALH). Among 22 samples that were allocated in a 37 degrees C, 5% CO2 incubator, the mean MSC after 3 hours was significantly higher following IxaPrep preparation than following Percoll preparation (63.2 x 10(6)/mL vs. 42.8 x 10(6)/mL, p < .03). VCL and VSL were much higher after IxaPrep preparation than after Percoll preparation, both at 3 hours (p < .01) and at 24 hours (p < .03). ALH was also higher after IxaPrep preparation than after Percoll preparation, and it was statistically significant after 3 hours of incubation (p < .03). We conclude that the IxaPrep gradient may be adopted as the preferred method to the Percoll gradient in preparing spermatozoa for assisted reproduction because of the spermatozoa's persistent and better motion activities after incubation.

Fractions of Percoll eliminated sperm: increased sperm yield in percoll wash

Sperm preparation by Percoll is one of the most widely used techniques, but it has the disadvantage of producing a low final yield of motile sperm. This study compared the quality of Percoll-eliminated sperm with that of Percoll recovered sperm to determine if the profile of the Percoll preparation could be improved. Semen specimens were fractionated by discontinuous Percoll gradient column. This resulted in 4 sperm fractions: sperm retained in the semen (SRS), sperm clumped at the interface of 40 and 80% Percoll (SCI), sperm scattered in the column (SSC), and sperm-forming pellet, called Percoll-recovered sperm (PRS). The sperm fractions were evaluated for count, motility, viability, vitality, and morphology. The SRS exhibited the lowest motility, viability, and vitality (40, 68, and 64%, respectively), which were significantly different from those of SCI, SSC, and PRS. The motility, viability, and vitality differences between SSC and PRS did not reach a statistically significant level. Good motility (grades a and b) was found in SSC (73%) when compared with that of PRS (82%). The lower part of SSC and PRS exhibited identical sperm morphology. The Percoll sperm recovery was 18%, but if SSC is combined with PRS, the total recovery becomes 40%. These data suggest that the SSC fraction, particularly the lower part, which maintains the physical contact with the PRS, can be pooled together to increase the final sperm yield without compromising the quality of the sperm to be used for insemination.

Comparison between a two-layer discontinuous Percoll gradient and swim-up for sperm preparation on normal and abnormal semen samples

PURPOSE

This work was to compare the effects of Percoll gradient and swim-up treatments for sperm preparation on the percentage of progressive motility, recovery of motile sperm, removal of debris, percentage of normal forms according to strict criteria, and movement characteristics of sperm using computer-assisted velocity analysis.

RESULTS

In total, 50 semen samples from 50 patients were tested and divided into two groups: a normal group (n = 27) with normal parameters and an abnormal group (n = 23) with abnormal parameters. The results in both the normal and abnormal groups revealed that the sperm concentration in the Percoll samples was significantly greater than that in the swim-up samples. Although the percentage of progressive motility was greater in the swim-up samples than in the Percoll samples, the number of motile sperm, reflecting the percentage of motile sperm recovery, was till greater in the Percoll samples. The debris of semen was equally removed by both methods and the percentage of normal forms was also similar in the samples treated according to these two procedures. Both curvilinear velocity (VCL) and straight-line velocity (VSL) of sperm were significantly greater in the swim-up samples than in the Percoll samples. Sperm from the swim-up procedure also showed a greater mean amplitude of lateral head displacement than that from the Percoll gradient procedure, but the distinction was insignificant.

CONCLUSION

The Percoll gradient technique, by recovering more motile sperm, may be applied to prepare oligospermic samples. The swim-up method may become the standard choice to prepare normal semen which could obtain sufficiently motile sperm, due to its simplicity and recovered sperm with superior motility.

Acrosin activity of human sperm did not correlate with IVF

To evaluate the predicting value of sperm acrosin activity in human, the acrosin activity index (AAI) was measured in 95 semen samples from patients participating in an IVF program. All patients had at least two mature oocytes. Of 95 patients, 84 had successful fertilization and 11 failed to fertilize all oocytes in vitro. The numbers of mature oocytes were similar between fertilization and nonfertilization groups. The mean AAI, measured using a commercially available (Accu-Sperm) acrosin activity assay, was greater in the fertilization group than in the nonfertilization group, but the difference was not significant. There was no correlation between AAI and the in vitro fertilization rate of mature oocytes. The relation between AAI and semen parameters also showed no significant difference. It would appear that measurement of AAI inaccurately reflects in vitro fertilizability of human sperm.