Human sperm cryopreservation is an increasingly mature technique in assisted reproduction. However, conventional sperm cryopreservation is not suitable for the cryopreservation of small numbers of sperm. The solution to the cryopreservation of small numbers of sperm may contribute a lot to the clinical treatment of asthenospermia, oligospermia and azoospermatism. Recently, many researchers focus on searching for appropriate carriers for the cryopreservation of small numbers of sperm. This article outlines the effects of current cryopreservation methods including empty zona pellucida, microdrops, other mocrocarriers, testicular tissue cryopreservation and testicular sperm and epididymal sperm refrigeration.
Cryopreservation ; methods ; Humans ; Male ; Semen Preservation ; methods ; Testis

Despite the worldwide application of sperm-freezing technology as a means of preserving male fertility functions, few reports are seen about the transmission of microorganisms to cryopreserved sperm via contaminated liquid nitrogen (LN). Although the risk of cross-contamination between samples stored in liquid nitrogen is "vanishingly small", it must be accepted as a finite risk and all reasonable measures taken to reduce the likelihood of its occurrence. Moreover, all methods employed, including collection, cryopreservation, storage and thawing of human sperm as well as the clinical use of cryobanked human sperm, must reduce the risk of contamination from any source throughout the entire process.
Cryopreservation ; methods ; Equipment Contamination ; Humans ; Male ; Semen Preservation ; methods

Human sperm cryopreservation has been widely applied in human assisted reproduction technologies, but ultra-low temperature may damage the structure and function of sperm, which in turn may affect the success rate of human reproductive technology. However, this view is not yet universally accepted. Researchers around the world are endeavoring for the mechanisms of cyrodamage and discoveries of cryo-protection. This article gives an overview on the types of human sperm cryodamage, mechanisms of sperm functional changes, and latest discoveries of cryo-protection.
Cryopreservation ; Humans ; Male ; Semen Preservation ; adverse effects ; methods

OBJECTIVETo provide a more effective cryoprotective medium (CPM), effect of union of albumin and egg yolk on human sperm cryopreservation was studied.

METHODSEgg yolk-glycerol-sodium citrate was regarded as CPM of the control group and egg yolk-glycerol-sodium citrate with different concentrations of albumin (1, 2, 3, 4, 5 g/L) were regarded as CPMs of experiment groups. Before and after cryopreservation, sperm movement parameters were assessed by using computer-aided sperm analyzer (CASA) system, and then egg yolk-glycerol-sodium citrate group added 1 g/L albumin was selected, whose movement parameters were the best among the experimental groups, and egg yolk-glycerol-sodium citrateto group as the control to compare sperm survival rate, membrane integrity, function of mitochondrion and ultrastruction.

RESULTSSperm in egg yolk-glycerol-sodium citrate added I g/L albumin showed significantly higher motility, viability than those in the control group and other experimental groups (P < 0.05). Sperm in egg yolk-glycerol-sodium citrate group added 1 g/L albumin had significantly higher survival rate, head unpigmenting rate than those in control group (P < 0.05). Sperm in egg yolk-glycerol-sodium citrate group added I g/L albumin manifested significantly higher succinate dehydrogenase (SDH) activity than that in control group (P < 0.05) and had better ultrastructure than that in control group.

CONCLUSIONUnion of two kinds of albumin and egg yolk has better effects on human sperm cryopreservation than those of solitary use of egg yolk. The action of albumin is related to its concentration, and albumin combining with egg yolk may have plus and complementary effects on human sperm cryopreservation.

Adult ; Albumins ; Cryopreservation ; Egg Yolk ; Humans ; Male ; Semen Preservation ; methods

Fertility preservation is a hotspot of research in reproductive medicine, and that of male adolescent cancer patients is drawing even more attention from reproductive and oncologic clinicians. Both cancer and its treatment can decrease semen quality and even induce irreversible damage to fertility. Sperm cryopreservation is an effective method for fertility preservation. In the past few years, marked advances have been made in the cryopreservation, transplantation, and in vitro culture of testis tissue and stem spermatogonial cells. Although still experimental, these approaches may offer some options to those with no mature sperm in the testis. Unfortunately, very few people know and participate in the studies of fertility preservation and the utilization rate of cryopreserved sperm remains low. Therefor reproductive physicians and oncologists are required to make more efforts to search for effective fertility preservation methods for male adolescent cancer patients.
Adolescent ; Cryopreservation ; Fertility Preservation ; methods ; Humans ; Male ; Neoplasms ; therapy ; Semen Analysis ; Semen Preservation ; methods ; Spermatogonia ; Testis ; cytology

OBJECTIVETo study the effect of direct fumigation on the post-thaw recovery rate of cryopreserved spermatozoa, and to search for a best method for human sperm cryopreservation.

METHODSWe collected semen samples from 100 donors conforming to the normal reference values in WHO Laboratory Manual for the Examination and Processing of Human Semen (5th Ed), divided them into two groups, and subjected them to cryopreservation by programmable freezing (Group A) and direct fumigation (Group B), respectively. We detected the progressive motility of pre-freezing and post-thaw sperm with a computer-assisted semen analyzer, and compared the effects of the two methods on the functional integrity of sperm membrane and the rate of abnormal sperm using the percentage of hypo-osmotic swelling sperm and modified Papanicolaou staining.

RESULTSStatistically significant differences were found in post-thaw sperm progressive motility between the Groups A and B ([34.0 +/- 18.4]% vs [43.0 +/- 19.5]%, P<0.05), both remarkably decreased as compared with pre-freezing ([57.0 +/- 16.7]%, P<0.05). Such differences were also found in the post-thaw recovery rate of progressively motile sperm between the two groups ([52.2 +/- 20.6]% vs [67.1 +/- 20.0]%, P<0.05). The post-thaw percentage of hypo-osmotic swelling sperm was obviously decreased in both Groups A and B ([67.1 +/- 11.1]% and [70.6 +/- 10.0]%) in comparison with pre-freezing ([84.5 +/- 7.5]%, P<0.05), with significant differences between A and B (P<0.05). However, the rate of sperm abnormality was evidently increased in Groups A and B ([85.0 +/- 8.7% and [85.7 +/- 9.1]%), significantly higher than pre-freezing ([77.8 +/- 9.6]%, P<0.05), but with no significant differences between A and B (P>0.05).

CONCLUSIONDirect fumigation is superior to programmable freezing for its easier operation, wider application, and higher sperm recovery rate.

Adult ; Cryopreservation ; methods ; Humans ; Male ; Semen Analysis ; Semen Preservation ; methods ; Sperm Motility ; Spermatozoa ; Young Adult

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*

OBJECTIVETo investigate the influence of different methods of semen preservation and processing on sperm DNA integrity.

METHODSWe collected semen samples from 100 normozoospermic male volunteers and, following homogeneous mixing, preserved them by means of snap freezing, slow freezing, or at the room temperature for 4 and 24 hours. Meanwhile we processed the semen by washing, swim-up, and density gradient centrifugation (DGC). Then we obtained the sperm DNA fragmentation index (DFI) by sperm chromatin dispersion test and measured total sperm motility and DFI after cultured for 24 hours following processing.

RESULTSThe sperm DFIs after 4 hours of preservation by snap freezing, slow freezing, and at the room temperature were (27.3 ± 6.4)%, (26.9 ± 6.1)%, and (24.7 ± 6.8)%, respectively, and that after preserved at the room temperature for 24 hours was (35.6 ± 9.0)%, with statistically significant differences between the first three and the 24-hour room temperature preservation groups (P < 0.05) but not among the former three groups (P > 0.05). The sperm DFI was significantly higher in the samples processed by washing ([13.7 ± 2.0]%) than in those processed by swim-up ([9.1 ± 1.3]%) and DGC ([8.0 ± 2.5]%) (P < 0.05), and it was the lowest in the DGC group after 24-hour culture ([11.5 ± 4.2]%) as compared with the other groups (P < 0.05).

CONCLUSIONSperm DNA integrity is influenced by different semen preservation conditions and processing methods.

Centrifugation, Density Gradient ; DNA Fragmentation ; Humans ; Male ; Semen ; Semen Analysis ; Semen Preservation ; methods ; Sperm Motility ; Spermatozoa ; cytology

OBJECTIVETo investigate the effect of pre-freezing equilibration on the cryo-survival of human sperm and to optimize the protocol of direct fumigation for the freeze-thawing of human sperm.

METHODSWe collected 50 semen samples from healthy donors, each subjected to cryopreservation with 3 different methods: non-equilibration freezing (Group A), 10-min equilibration at room temperature before freezing (Group B), and 10-min equilibration at 4 degrees C before freezing (Group C). We examined all the post-thaw semen samples by computer-assisted semen analysis for the sperm motility parameters, and detected the sperm vitality and deformity index (SDI).

RESULTSThe recovery rate of progressive sperm motility was (61.88 +/- 16.94)% in Group C, remarkably higher than in A ([48.61 +/- 16.44]%) and B ([49.41 +/- 13.77]%) (P < 0.05), but with no significant difference between the latter two. And there were no significant differences in sperm vitality and SDI among the three groups.

CONCLUSIONTen-minute equilibration at 4 degrees C before freezing can evidently improve the progressive motility of sperm in addition to its advantages of easy operation and controllable experimental condition.

Adult ; Cryopreservation ; methods ; Humans ; Male ; Semen Analysis ; Semen Preservation ; methods ; Sperm Banks ; Sperm Count ; Sperm Motility ; Young Adult

Sperm cryopreservation has revolutionized the field of assisted reproduction. However, it causes cryodamage to the structure and function of spermatozoa during the freezing-thawing process. Optimization of sperm cryopreservation is necessary for the preservation of male fertility. Cryodamage can be reduced effectively by such methods as improvement of semen quality before freezing, spermatozoal selection, addition of optimal cryoprotectants and application of appropriate thawing techniques. Recent studies focus on cryobiology, improvement of freezing-thawing methods, especially for poor quality semen, and evaluation criteria for post-thaw spermatozoa.
Cryopreservation ; methods ; Humans ; Male ; Semen Preservation ; methods ; Sperm Count ; Sperm Motility ; Spermatozoa ; cytology ; physiology