Cryopreservation of human spermatozoa with penetrating and non-penetrating cryoprotectants

Сryopreserved spermatozoa are widely used in infertility treatment by assisted reproductive technologies. However, the spermatozoa survival rate remains low in patients with oligoastenoteratozoospermia. Therefore the development of effective cryopreservation methods for spermatozoa from pathospermia is relevant. The effectiveness of cryopreservation spermatozoa from oligoastenoteratozoospermia man using penetrating and non-penetrating cryoprotectants was compared. Sperm motility, viability and morphological characteristics were evaluated after cryopreservation with glycerol and polyvinylpyrrolidone. The average number of spermatozoa count in fresh ejaculate was (11.0±0.2) mln/ml. After isolation of active motile fraction the number of cells was (3.8±0.3) mln/ml and (84.3±8.4) % from them were motile (group 3). (78.8±6.6) % of spermatozoa cryopreserved with glycerol (group 1) and (41.4±8.1) % cryopreserved with polyvinylpyrrolidone (group 2) remained active motile. The spermatozoa viability after cryopreservation was (82.1±8.6) % and (89.6±8.6) % in group 1 and 2, respectively. Despite the high rate of spermatozoa survival in group 1 the number of motile cells decreased to (27.3±4.8) % after cryoprotectant removing stage. Morphological analysis revealed that the incidence of spermatozoa head abnormalities was (25.97±2.67), (19.21±2.67) and (20.57±1.19) % in group 1–3, respectively. The differences of spermatozoa midpiece and tail abnormalities in the study groups were statistically insignificant. The use of polyvinylpyrrolidone as a cryoprotectant allows preserving 90 % of survived spermatozoa from oligoastenoteratozoospermia men after freeze/thawing. The set of spermatozoa head, neck and midpiece abnormalities is significantly lower after cryopreservation with polyvinylpyrrolidone compared with routine method with glycerol. Two-stage spermatozoa cryopreservation method with polyvinylpyrrolidone is promising for assisted reproductive technologies since spermatozoa can be used immediately after warming for oocyte fertilization without cryoprotectant removing step.