Azoospermia is characterized by the absence of sperm in the ejaculate and is categorized into obstructive azoospermia (OA) and nonobstructive azoospermia (NOA). For men with NOA, testicular sperm extraction (TESE) is the only method to obtain sperm for assisted reproductive technology (ART). Given the rarity of these sperm and the unpredictable success of subsequent retrieval attempts, cryopreservation of microdissection-TESE-obtained sperm is essential. Effective cryopreservation prevents the need for repeated surgical procedures and supports future ART attempts. After first delving into the physiological and molecular aspects of sperm cryopreservation, this review aims to examine the current methods and devices for preserving small numbers of sperm. It presents conventional freezing and vitrification techniques, evaluating their respective strengths and limitations in effectively preserving rare sperm, and compares the efficacy of using fresh versus cryopreserved testicular sperm.
Humans ; Cryopreservation/methods* ; Male ; Sperm Retrieval ; Azoospermia/therapy* ; Semen Preservation/methods* ; Spermatozoa ; Vitrification

The use of fresh versus frozen spermatozoa in men with nonobstructive azoospermia (NOA) undergoing in vitro fertilization (IVF) has been a debated hot topic among reproductive specialists. Each approach presents distinct advantages and disadvantages, with fresh sperm typically showing superior sperm quality, while frozen sperm offers logistical flexibility and a reliable backup for repeated cycles. This review summarizes the latest advancements in sperm retrieval and cryopreservation techniques, providing practitioners with a comprehensive analysis of each option's strengths and limitations. Comparative studies indicate that, although fresh sperm often has better quality metrics, cryopreservation methods such as vitrification have significantly improved postthaw outcomes, making frozen sperm a viable choice in assisted reproductive technologies (ART). The findings show comparable rates for fertilization, implantation, clinical pregnancy, and live birth between fresh and frozen microdissection testicular sperm extraction (micro-TESE) sperm in many cases, although patient-specific factors such as timing, cost-effectiveness, and procedural convenience should guide the final decision. Ultimately, the choice of using fresh or frozen sperm should align with the individual needs and conditions of patients. This tailored approach, supported by the latest advancements, can optimize ART outcomes and provide personalized reproductive care.
Humans ; Cryopreservation/methods* ; Male ; Sperm Retrieval ; Semen Preservation/methods* ; Azoospermia/therapy* ; Pregnancy ; Female ; Fertilization in Vitro ; Spermatozoa ; Microdissection ; Pregnancy Rate

Human sperm cryopreservation is an effective approach to the management and preservation of male fertility, and sperm quality after cryo-resuscitation is an important factor influencing the clinical outcomes of assisted reproductive technology. Either donor or autologous sperm cryopreservation is subjected to the impact of cryoinjury on semen quality. Studies show that oxidative stress has a negative impact on sperm function during sperm freezing and thawing, and antioxidants, as compounds to treat, scavenge, inhibit, or impede oxidative chain reaction that forms reactive oxygen species or counteracts their effects, can protect sperm cells from oxidative stress and are essential for sperm function. This review describes the mechanism of oxidative stress in sperm freezing and thawing, presents an overview of the advances in the studies of various commonly used antioxidants in cryopreservation of human sperm, and provides some reference for further research on the effects of antioxidants and their clinical application.
Humans ; Cryopreservation/methods* ; Antioxidants/pharmacology* ; Male ; Semen Preservation/methods* ; Spermatozoa/drug effects* ; Oxidative Stress

In the 1960s, sperm cryopreservation was developed as a method to preserve fertility. Currently, techniques for the cryopreservation of human spermatozoa have been widely used in assisted reproduction. However, although sperm cryobiology has made notable achievements, the optimal method for the recovery of viable spermatozoa after cryopreservation remains elusive. Postthawing sperm quality can be affected by cryoprotectants, ice formation, storage conditions, and osmotic stress during the freezing process. This review discusses recent advances in different cryopreservation techniques, cryoprotectants, and freezing and thawing methods during cryopreservation and new indications for the use of cryopreserved spermatozoa.
Humans ; Male ; Semen Preservation/methods* ; Sperm Motility ; Semen ; Cryopreservation/methods* ; Spermatozoa ; Cryoprotective Agents/pharmacology*

Cryopreservation ; Humans ; Male ; Methanol ; Nitrogen ; Papillomavirus Infections ; Pilot Projects ; Semen Preservation ; Spermatozoa

PURPOSE: Sperm cryopreservation before cancer treatment is the most effective method to preserve the fertility of male patients. We present our 21 years experience with sperm cryopreservation for cancer patients, including an examination of semen quality, the current status of cryopreserved sperm, and the rate of sperm use for assisted reproductive technology (ART). MATERIALS AND METHODS: A total of 721 cancer patients at Fertility Center of CHA Gangnam Medical Center successfully performed sperm cryopreservation for fertility preservation from January 1996 to December 2016. Medical chart review was used to analyze patient age, marital status, cancer type, semen volume, sperm counts and motility, length of storage, and current banking status. RESULTS: The major cancers of the 721 patients were leukemia (28.4%), lymphoma (18.3%), testis cancer (10.0%). The mean age at cryopreservation was 27.0 years, and 111 patients (15.4%) performed sperm cryopreservation during or after cancer treatment. The mean sperm concentration was 66.7±66.3 ×106/mL and the mean sperm motility was 33.8%±16.3%. During median follow-up duration of 75 months (range, 1–226 months), 44 patients (6.1%) used their banked sperm at our fertility center for ART and 9 patients (1.2%) transferred their banked sperm to another center. The median duration from cryopreservation to use was 51 months (range, 1–158 months). CONCLUSIONS: Sperm cryopreservation before gonadotoxic treatment is the most reliable method to preserve the fertility of male cancer patients. Sperm cryopreservation should be offered as a standard of care for all men planning cancer therapy.
Cryopreservation ; Fertility Preservation ; Fertility ; Follow-Up Studies ; Humans ; Leukemia ; Lymphoma ; Male ; Marital Status ; Methods ; Reproductive Techniques, Assisted ; Semen ; Semen Analysis ; Semen Preservation ; Sperm Count ; Sperm Motility ; Spermatozoa ; Standard of Care ; Testicular Neoplasms

OBJECTIVE: The aim of this study was to investigate DNA fragmentation status in human spermatozoa according to specific tail swelling patterns determined via hypo-osmotic swelling test (HOST).METHODS: Frozen semen samples from 21 healthy donors were thawed and prepared by the swim-up technique for use in intracytoplasmic sperm injection. The semen samples were treated for 5 minutes as part of the HOST procedure and then underwent the sperm chromatin dispersion test using a Halosperm kit. DNA fragmentation status (large halo, medium halo, small halo, no halo, or degraded) and the specific tail swelling pattern (“a”–“g”) were assessed at the level of a single spermatozoon. A total of 42,000 spermatozoa were analyzed, and the percentage of spermatozoa without DNA fragmentation (as evidenced by a large or medium halo) was assessed according to the specific tail swelling patterns observed.RESULTS: The HOST examinations showed that >93% of spermatozoa across all types displayed no DNA fragmentation. The percentage of spermatozoa without DNA fragmentation was 100% in type “d”, 98.67% in type “g”, and 98.17% in type “f” spermatozoa.CONCLUSION: We found that the type “d” spermatozoa displayed no DNA fragmentation, but the other types of spermatozoa also displayed very low rates of DNA fragmentation. This result may be associated with the processing of the spermatozoa by density gradient centrifugation and the swim-up technique.
Centrifugation, Density Gradient ; Chromatin ; DNA Fragmentation ; DNA ; Humans ; Infertility ; Semen ; Semen Preservation ; Sperm Head ; Sperm Injections, Intracytoplasmic ; Spermatozoa ; Tail ; Tissue Donors

Onco-testicular sperm extraction is used to preserve fertility in patients with bilateral testicular tumors and azoospermia. We report the case of a testicular tumor in the solitary testis of a patient who had previously undergone successful contralateral orchiectomy and whose sperm was preserved by onco-testicular sperm extraction. A 35-year-old patient presented with swelling of his right scrotum that had lasted for 1 month. His medical history included a contralateral orchiectomy during childhood. Ultrasonography revealed a mosaic echoic area in his scrotum, suggesting a testicular tumor. The lesion was palpated within the normal testicular tissue along its edge and semen analysis showed azoospermia. Radical inguinal orchiectomy and onco-testicular sperm extraction were performed simultaneously. Motile spermatozoa were extracted from normal seminiferous tubules under microscopy and were frozen. Eventual intracytoplasmic sperm injection using the frozen spermatozoa is planned. Onco-testicular sperm extraction is an important fertility preservation method in patients with bilateral testicular tumors or a history of a previous contralateral orchiectomy.
Adult ; Azoospermia* ; Fertility ; Fertility Preservation ; Humans ; Infertility, Male ; Male ; Methods ; Microscopy ; Orchiectomy ; Scrotum ; Semen Analysis ; Seminiferous Tubules ; Sperm Injections, Intracytoplasmic ; Sperm Retrieval ; Spermatozoa* ; Testicular Neoplasms* ; Testis* ; Ultrasonography

ObjectiveTo investigate the effects of resveratrol in the cryopreservation medium on the quality and function of post-thaw sperm.

METHODSSemen samples were obtained from 50 normozoospermic and 50 oligoasthenozoospermic men, liquefied and then cryopreserved in the glycerol-egg yolk-citrate (GEYC) medium with or without 30 μmol/L resveratrol. Sperm motility, viability and acrosome reaction (AR) were examined before and after thawing. Sperm lipid peroxidation and the level of reactive oxygen species (ROS) were measured using commercial malondialdehyde (MDA) and the ROS assay kit. Sperm mitochondrial membrane potential (MMP) and DNA damage were determined by Rhodamine 123 staining and TUNEL.

RESULTSThe percentage of progressively motile sperm (PMS), total sperm motility, sperm viability, MMP and AR were significantly decreased (P <0.05) while the levels of sperm ROS, MDA and DNA fragmentation index (DFI) remarkably increased in both the normozoospermia and oligoasthenozoospermia groups after cryopreservation as compared with those in the fresh ejaculate (P <0.05). In comparison with the non-resveratrol control, the post-thaw sperm cryopreserved with 30 μmol/L resveratrol showed markedly higher PMS (［32.7 ± 4.8］ vs ［43.1 ± 6.3］ %, P <0.05), total motility (［44.8 ± 6.9］ vs ［56.9 ± 7.4］ %, P <0.05), viability (［52.3 ± 6.1］ vs ［67.5 ± 5.6］ %, P <0.05), MMP (［56.5 ± 7.0］ vs ［63.4 ± 7.5］ %, P <0.05) and AR (［16.6 ± 3.8］ vs ［26.3 ± 4.7］ %, P <0.05) but lower ROS, MDA and DFI (all P <0.05) in the normozoospermia group, and so did the post-thaw sperm in the oligoasthenozoospermia group, with a particularly lower DFI (［28.5 ± 4.8］ vs ［36.3 ± 5.7］%, P <0.01).

CONCLUSIONSResveratrol in the cryopreservation medium can improve the quality and function of post-thaw human sperm by reducing cryopreservation-induced sperm injury and the level of ROS.

Acrosome ; drug effects ; Animals ; Antioxidants ; pharmacology ; Cryopreservation ; methods ; DNA Fragmentation ; Humans ; Lipid Peroxidation ; Male ; Malondialdehyde ; Membrane Potential, Mitochondrial ; Reactive Oxygen Species ; analysis ; Resveratrol ; pharmacology ; Semen Analysis ; Semen Preservation ; adverse effects ; Sperm Motility ; drug effects ; Spermatozoa ; drug effects ; physiology

Sperm cryopreservation has been widely used in assisted reproduction, but conventional techniques are not suitable for the cryopreservation of small numbers of sperm. The application of the single sperm cryopreservation technique has significantly improved the clinical treatment of cryptozoospermia and non-obstructive azoospermia. Ever since Cohen et al first developed the method of single sperm cryopreservation in 1997, constant efforts have been made to develop the carriers for this technique. In this review, we mainly discuss the existing methods and clinical outcomes of single sperm cryopreservation.
Azoospermia ; therapy ; Cryopreservation ; methods ; Heterozygote ; Humans ; Male ; Oligospermia ; therapy ; Reproduction ; Semen Preservation ; methods ; Spermatozoa