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 aim of this investigation was to determine the optimal storage medium for testicular hypothermic transportation and identify the ideal concentration for the application of the protective agent 5-aminolevulinic acid (5-ALA). Furthermore, this study aimed to explore the underlying mechanism of the protective effects of 5-ALA. First, we collected and stored mouse testicular fragments in different media, including Hank's balanced salt solution (HBSS; n = 5), Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12 (DMEM/F12; n = 5), and alpha-minimum essential medium (αMEM; n = 5). Storage of testicular tissue in HBSS preserved the integrity of testicular morphology better than that in the DMEM/F12 group ( P < 0.05) and the αMEM group ( P < 0.01). Testicular fragments were subsequently placed in HBSS with various concentrations of 5-ALA (0 [control], 1 mmol l -1 , 2 mmol l -1 , and 5 mmol l -1 ) to determine the most effective concentration of 5-ALA. The 2 mmol l -1 5-ALA group ( n = 3) presented the highest positive rate of spermatogonial stem cells compared with those in the control, 1 mmol l -1 , and 5 mmol l -1 5-ALA groups. Finally, the tissue fragments were preserved in HBSS with control ( n = 3) and 2 mmol l -1 5-ALA ( n = 3) under low-temperature conditions. A comparative analysis was performed against fresh testes ( n = 3) to elucidate the underlying mechanism of 5-ALA. Gene set enrichment analysis (GSEA) for WikiPathways revealed that the p38 mitogen-activated protein kinase (MAPK) signaling pathway was downregulated in the 2 mmol l -1 5-ALA group compared with that in the control group (normalized enrichment score [NES] = -1.57, false discovery rate [FDR] = 0.229, and P = 0.019). In conclusion, these data suggest that using 2 mmol l -1 5-ALA in HBSS effectively protected the viability of spermatogonial stem cells upon hypothermic transportation.
Male ; Animals ; Testis/cytology* ; Aminolevulinic Acid/pharmacology* ; Mice ; Organ Preservation/methods* ; Organ Preservation Solutions/pharmacology* ; Cryopreservation/methods*

Since the early days of assisted reproductive technology (ART), the importance of sperm processing, employed to separate the motile, morphologically normal sperm from the semen, has been shown to be beneficial. The aim of the semen processing technique has been to remove seminal plasma and facilitate capacitation. Additionally, the presence of leukocytes, bacteria, and dead spermatozoa has been shown to be detrimental as it may cause oxidative stress that has an adverse effect on oocyte fertilization and embryo development. Hence, removal of leukocytes, bacteria, and dead spermatozoa is an important step of sperm processing for assisted reproduction. Currently, several sperm processing techniques have been evolved and optimized in the field of assisted reproduction. The requirements for in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and testicular sperm extraction (TESE) are different than those of intrauterine insemination (IUI). The yield of as many motile, morphologically normal sperm as possible is a prerequisite for the success of IVF insemination procedure. In ICSI, where injection of a single spermatozoon into the oocyte is performed by the embryologist, sperm selection techniques play a crucial role in the ICSI procedure. Finally, sperm retrieval in TESE samples with very low number of sperm may be challenging and requires extra care during sample processing. Additionally, sperm cryopreservation is necessary in TESE cases in order to avoid multiple biopsies.
Humans ; Sperm Injections, Intracytoplasmic/methods* ; Male ; Fertilization in Vitro/methods* ; Sperm Retrieval ; Andrology/methods* ; Cryopreservation ; Female ; Spermatozoa

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

As prepubertal boys do not yet produce spermatozoa, they cannot rely on sperm cryopreservation for fertility preservation before gonadotoxic therapy, such as high-dose alkylating agents or radiotherapy in the case of childhood cancers. According to the current guidelines, cryopreservation of testicular biopsies containing spermatogonial stem cells (SSCs) may be proposed to high-risk patients for potential later therapeutic use to fulfill the patients' wish for a biological child. One promising technique for human in vitro spermatogenesis and in vitro propagation of human SSCs is microfluidic (MF) culture, in which cells or tissues are subjected to a continuous flow of medium. This provides exact control over such parameters as nutrient content and gradients, as well as the removal of waste metabolites. While MF has been shown to maintain tissues and cell populations of organs for longer than conventional in vitro culture techniques, it has not been widely used for testicular in vitro culture. MF could advance human testicular in vitro culture and is also applicable to reprotoxicity studies. This review summarizes the findings and achievements of testis-on-chip (ToC) setups to date and discusses the benefits and limitations of these for spermatogenesis in vitro and toxicity assessment.
Humans ; Male ; Spermatogenesis/physiology* ; Testis/cytology* ; Cryopreservation ; Cell Culture Techniques/methods* ; Microfluidics/methods* ; Animals

OBJECTIVE: To compare and analyze the changes of aggregation rate and routine parameters of platelets stored in temperature cycle, cold storage at 4 ℃ and oscillating storage at 22 ℃, so as to provide more experimental data for platelet preservation methods. METHODS: Blood samples were collected at 5 time points on the 1^st, 2^nd, 3^rd, 4^th and 6^th day after platelet cycling preservation at temperature, cold storage at 4 ℃, and oscillating storage at 22 ℃. Platelet maximum aggregation rate (MAR) and routine parameters including platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW) and platelet-larger cell ratio (P-LCR) were detected. RESULTS: The platelet MAR of three groups showed a significant decrease trend with the preservation time, the fastest decrease was in the 22 ℃ group, the slowest was in the 4 ℃ group, and the temperature cycle group was between the two groups. On the 3^rd day of preservation, the platelet MAR in 4 ℃ group was still in the normal range (MAR>60%), while in temperature cycle group was about 50%, and in 22 ℃ group was the lowest. On the 4^th day of preservation, platelet MAR in all the three groups was lower than 50%, and that in temperature cycle group was significantly lower than in 4 ℃ group but higher than in 22 ℃ group (both P < 0.05). On the 6^th day of preservation, platelet MAR in the temperature cycle group was significantly lower than that in the 4 ℃ group ( P <0.05), but there was no statistically significant difference compared to 22 ℃ group (P >0.05). PLT values in the three groups were all significantly decreased with the preservation time extension, and were significantly lower than those in the early stage of preservation within 6 days (all P < 0.05). PDW in temperature cycle group had no significant change within 6 days of preservation, but MPV and P-LCR were significantly increased. MPV, PDW and P-LCR all decreased significantly in 4 ℃ group within 6 days of preservation but increased in 22 ℃ group. Under the same storage days, PLT value of temperature cycle group had no significant difference with that of 4 ℃ group and 22 ℃ group, while MPV, PDW and P-LCR values were significantly higher than 4 ℃ group but lower than 22 ℃ group (all P < 0.05). CONCLUSION The aggregation function and routine parameters changes of temperature circulating preserved platelets are between 4 and 22 ℃.
Humans ; Platelet Aggregation ; Blood Preservation/methods* ; Temperature ; Blood Platelets ; Platelet Count ; Mean Platelet Volume ; Cryopreservation/methods* ; Cold Temperature

OBJECTIVE: The aim of this study is to explore the influencing factors of fertility preservation decision-making in testicular cancer patient and provide a basis for clinical decision. METHODS: A descriptive qualitative study was conducted using purposive sampling in 18 testicular cancer patients. Semi-structured interviews were performed, and data were analyzed through content analysis. RESULTS: A total of 3 themes and 10 subthemes were extracted including individual factors (fertility circumstance, concerns about sperm cryopreservation efficacy/quality, the preferred choice between treatment and fertility preservation, confidence in future fertility), medical factors (physicians' recommendations on fertility preservation, fertility-related information, urgency of treatment), and socio-environmental factors (traditional beliefs of fertility, family/partner support, accessibility/cost of cryopreservation). CONCLUSION This study highlights many influencing factors of fertility preservation decision-making in testicular cancer patients, emphasizing the need for clinicians to enhance awareness of fertility preservation, provide timely and targeted information, and advocate for policy interventions to reduce financial barriers. Strengthening healthcare support and systemic safeguards may optimize patients' decision-making outcomes.
Humans ; Male ; Fertility Preservation ; Testicular Neoplasms/therapy* ; Decision Making ; Qualitative Research ; Cryopreservation ; Adult ; Infertility, Male/prevention & control*

Cryopreservation is the primary technique for in vitro preservation of allogeneic tissue. However, its success is often hindered by factors such as low temperature, ischemia, and hypoxia. This study investigated the potential of Sini Decoction, known for its antioxidant and anti-apoptotic properties, to reduce cryopreservation-induced injury in rats' sciatic nerves. Sini Decoction was prepared according to the Chinese Pharmacopoeia, and its cytotoxicity on Rsc96 cells was assessed by using the CCK-8 method. Sini Decoction at concentrations of 4, 8, and 16 mg·mL~(-1), termed as low-(SL), medium-(SM), and high-(SH) doses group, was used for cryopreservation of rats' sciatic nerves. A normal control(NC) group and a fresh nerve control(fresh) group were set. Flow cytometry and TUNEL staining were used to detect the apoptosis of neural tissue cells after cryopreservation. Western blot was used to detect the expression of apoptosis-related proteins(Bcl-2, Bax, caspase-3, and caspase-8) and nerve regeneration proteins(NGF and BDNF) in vitro after cryopreservation. Oxidative damage of neural tissue after cryopreservation was evaluated by measuring levels of GSH, SOD, MDA, ROS, and ATP. Cryopreserved nerves were then used for allogeneic transplantation. One week after transplantation, CD4~+ and CD8~+ fluorescent double staining assessed inflammatory cell invasion in the transplanted nerve segment, and ELISA evaluated the expression of serum inflammatory factors(IL-1, IFN-γ, and TNF-α) in recipients. Twenty weeks after transplantation, electrophysiology and NF200 neurofilament staining were used to evaluate nerve regeneration. RESULTS:: showed that Sini Decoction at concentrations of below 32 mg·mL~(-1) exhibited no cytotoxicity to Rsc96 cells. During in vitro nerve cryopreservation, Sini Decoction significantly reduced cell apoptosis, ROS, and MDA production compared to the NC group. In the SH group, the protein expression of NGF and BDNF in vitro, as well as ATP, SOD, and GSH production, were significantly increased. In the rejection reaction one week after transplantation, compared to the fresh nerve transplantation group, the SL and SM groups showed reduced CD4~+ and CD8~+ T cell invasion in the transplanted nerve segment and down-regulated IL-1, IFN-γ, and TNF-α expression in recipient serum. Twenty weeks after transplantation, the electrophysiological test results of CMAP, NCV, and NF200 neurofilament protein fluorescent staining in the SM and SH groups were superior to those in the NC and fresh groups. These findings indicate that Sini Decoction offers protective benefits in the cryopreservation of rats' sciatic nerves and holds significant potential for the in vitro preservation of tissue and organs.
Animals ; Apoptosis/drug effects* ; Rats ; Oxidative Stress/drug effects* ; Sciatic Nerve/cytology* ; Cryopreservation ; Drugs, Chinese Herbal/administration & dosage* ; Male ; Rats, Sprague-Dawley ; Protective Agents/pharmacology*

This study assessed the feasibility of testis tissue cryopreservation (TTC) for fertility preservation in prepubescent boys with cryptorchidism. From January 2014 to December 2022, the University Hospital of Copenhagen (Rigshospitalet, Copenhagen, Denmark) implemented TTC for 56 boys with cryptorchidism to preserve their reproductive potential. Testis tissue samples were collected during orchiopexy (32 cases) or at subsequent follow-up procedures (24 cases), necessitated by an increased risk of infertility as indicated by hormonal assessments and/or findings from initial surgical biopsies. Testis samples were procured for TTC and pathological analysis. The cohort had an average age of 1.3 (range: 0.3-3.8) years at the time of orchiopexy, with 91.1% presenting bilateral cryptorchidism. The study revealed a median germ cell count of 0.39 (range: 0-2.88) per seminiferous tubule, with germ cells detected in 98.0% of the bilateral biopsies and 100% of the unilateral, indicating a substantial potential for fertility in these immature tissues. A dark spermatogonia (Ad) was detected in 37 out of 56 patients evaluated, with a median Ad spermatogonia count of 0.027 (range: 0.002-0.158) per seminiferous tubule. A total of 30.2% of the samples lacked Ad spermatogonia, indicative of potential gonadotrophin insufficiency. The median hormone levels measured were as follows: follicle-stimulating hormone (FSH) at 0.69 (range: 0.16-2.5) U l -1 , luteinizing hormone (LH) at 0.21 (range: 0.05-3.86) U l -1 , and inhibin B at 126 (range: 17-300) pg ml -1 . Despite early orchiopexy, 20%-25% of boys with cryptorchidism remain at risk for future infertility, substantiating the necessity of TTC as a precaution. The study highlights the need for refined predictive techniques to identify boys at higher risk of future infertility.
Humans ; Male ; Cryptorchidism/pathology* ; Cryopreservation ; Testis/pathology* ; Fertility Preservation/methods* ; Child, Preschool ; Infant ; Orchiopexy ; Spermatogonia/pathology* ; Infertility, Male/etiology*

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