Pentoxifylline treatment as a safe method for selecting viable testicular spermatozoa before cryopreservation of a small numbers of spermatozoa in azoospermia individuals.

Background: Single sperm cryopreservation (SSC) is a specific technique especially used in individuals with small numbers of sperm who suffered from non-obstructive azoospermia (NOA). Testicular specimens possess poor motility and low population of viable spermatozoa. Therefore, sperm selection methods such as applying pentoxifylline (PTX) may improve motility in these cases. The main aim of this study was to evaluate the protective effects of PTX on testicular spermatozoa before and after performing SSC.

Methods: Thirty testicular samples were obtained from men with azoospermia. This study was conducted in two phases. Phase 1 evaluated the effect of PTX for sperm selection before SSC. Twenty testicular samples were divided to two experimental groups: SSC without (I) and with PTX treatment (II). For PTX treatment spermatozoa were incubated with PTX at 37°C for 30 min and only motile spermatozoa were selected for SSC. In phase 2, ten testicular samples were cryopreserved with SSC and warming procedure was carried out in droplet with and without PTX. Motility and viability rates, morphology by motile sperm organelle morphology examination (MSOME), DNA fragmentation by sperm chromatin dispersion test (SCD) and mitochondrial membrane potential (MMP) were evaluated.

Results: In phase 1, post warm motility rate was higher in PTX exposed group compared to the unexposed group (25.6 ± 8.13 vs. 0.85 ± 2.1) (p > 0.00). Recovery rate, viability and morphology were not significantly different between groups. DNA integrity and MMP were also similar between both groups. In phase 2 although motility increased in PTX group compared to without PTX group (29.30 ± 12.73 vs. 1.90 ± 2.64) (p > 0.00), the viability rate was not different (70.40 ± 12.12 vs. 65.30 ± 11.87). All above mentioned parameters were similar between the two SSC groups.

Conclusions: Supplementation of testicular spermatozoa with PTX before cryopreservation increases motility and did not have adverse effects on viability, morphology, DNA integrity and MMP. PTX could be used as sperm selection method before single sperm cryopreservation, but PTX could not maintain motile the most of viable testicular sperms.