Effect of normal seminal plasma replacement on cryopreservation of sperm in patients with non-liquefied semen

Abstract

Objective: To explore the effects of normal seminal plasma replacement on cryopreservation of human non-liquefied spermatozoa. Methods: Sixty Semen samples (30 samples of normal semen and 30 samples of non-liquefied semen) were collected from infertile male patients in the Reproductive Medicine Center of Jingmen People's Hospital. After centrifugation, spermatozoa were divided into 5 aliquots, of which 2 aliquots were added with non-liquefied and normal seminal plasma, respectively. Computer-assisted semen analysis system (CASA) measured sperm motility after various periods of incubation (0, 0.5, 1 and 2 h). The remaining 3 aliquots of sperm were employed as follows for cryopreservation: a seminal plasma-free group in which sperm was preserved by adding sperm cryoprotectants; a non-liquefied semen-derived seminal plasma group for which sperm was added with non-liquefied plasma; a normal seminal plasma group for which sperm was added with normal seminal plasma. After the freezing-thawing process, sperm parameters, DNA integrity and ability to resist oxidative stress damage were again examined for these 3 groups. Results: Incubation of normal semen plasma, without liquefaction, can improve the sperm motility. After cryopreservation, sperm parameters were significantly lower versus those of the sample not cryopreserved. Normal semen plasma can reasonably protect the sperm of unliquefied semen and maintain the sperm parameters. It can also maintain the DNA integrity and prevent oxidative stress injury. Conclusion: Normal seminal plasma can maintain the semen key parameters after cryopreservation of non-liquefied semen. Protective effects observed with this normal seminal liquid might be due to the antioxidants remaining within the seminal liquid.