Acrosin activity negatively influences the cumulative live birth rate in patients undergoing IVF treatment.

RESEARCH QUESTION: Is acrosin activity related to cumulative live birth rate (CLBR) over 1 year after IVF, intracytoplasmic sperm injection (ICSI) treatment or both? DESIGN: Retrospective monocentric cohort study of 5704 couples who started IVF/ICSI treatments between 2016 and 2021. Acrosin activity was determined by a modified Kennedy method using a commercial kit. Patients were divided into two groups according to their acrosin activity: below 25 µIU/106 spermatozoa; and an acrosin activity 25 µIU/106 spermatozoa or above. Primary outcome was the CLBR, defined as an ongoing pregnancy leading to live birth that had arisen from all embryo transfers carried out within 1 year after the first ovum retrieval. Both conservative and optimistic methods were used for estimating CLBRs. RESULTS: The CLBRs of patients with an acrosin activity below 25 µIU/106 spermatozoa were found to be significantly lower than those of patients with an acrosin activity 25 µIU/106 spermatozoa or above by conservative (48.5% versus 55.4%, P = 0.02) and optimistic (63.7% versus 70.3%, P = 0.047) methods after adjusting for confounders. When acrosin activity was regarded as a continuous variable, significant negative relationships between acrosin activity and CLBR were identified in subgroups: young couples (men and women aged younger than 30 years) and couples from whom no more than 10 eggs were retrieved. CONCLUSION: Low acrosin activity levels were correlated with decreasing CLBRs over 1 year. These findings suggest that acrosin activity can be used as a predictor for CLBRs before starting IVF/ICSI treatment to enhance the effectiveness of counselling.

The correlation between sperm percentage with a small acrosome and unexplained in vitro fertilization failure.

PURPOSE: Since the unexplained in vitro fertilization failure occurs frequently, it is of great importance and clinical value to identify potential underlying predictors. This study aimed to explore whether the percentage of sperm with a small acrosome was correlated with unexplained in vitro fertilization failure. METHODS: A new acrosomal function evaluation index (the percentage of sperm with a small acrosome) was introduced into the analysis of sperm morphology. The association between the index and acrosome function by acrosin activity detection test and acrosome reaction test was investigated. In addition, the correlation with unexplained in vitro fertilization failure was further explored. Finally, the ROC curve was used to analyze the diagnostic efficacy on the failure of in vitro fertilization and the cutoff value was calculated. RESULTS: As the increasing of the percentage of sperm with a small acrosome, the value of acrosin activity, acrosome reaction rate, and in vitro fertilization rate were reduced, with a statistically significant difference (P < 0.05). The index in the low fertilization rate group was significantly higher than that in the normal fertilization rate group (P < 0.05). Finally, the results of ROC curve found that when the index was 43.5%, the sensitivity and specificity were 74.2% and 95.3%, respectively. CONCLUSION: The percentage of sperm with a small acrosome was positively correlated with unexplained in vitro fertilization failure, which could be potentially used as a prognostic index for the failure of in vitro fertilization. TRIAL REGISTRATION: [Ethics review acceptance No IIT20210339B].

Low acrosin activity is associated with decreased Spam1/acrosin expression and GSH deficiency-caused premature acrosome release of human sperm cells.

Low acrosin activity (LAA) is associated with sperm function anomaly and poor outcomes of in vitro fertilization. In this study, we confirm that 993 semen samples with LAA had a reduced sperm motility and low in vitro fertilization rate in comparison with 1332 normal controls (NC). Proteomic comparison between 11 LAA and 11 NC sperm samples identified 35 upregulated and 99 downregulated proteins in the LAA group. Indeed, proteomic data showed that acrosome enzymes Spam1 and Acrosin were among the downregulated proteins in the LAA group, which was validated by quantitative PCR and immunefluorescent staining of sperm cells. The KEEG pathway analysis revealed a deficiency of GSH and Gln biosynthesis in LAA sperm cells. Immunofluorescent staining of sperms and quantitative PCR verified downregulation of GLUL and GCLC, the key enzymes for GSH and Gln biosynthesis. Moreover, the results of ELISA assay confirmed low levels of GSH and Gln in LAA sperm cells. Mechanistic studies showed that addition of 10 mM H2O2 to semen samples led to a significant reduction of acrosin activity and sperm motility, most possibly by triggering premature acrosome release. In contrast, the presence of 20 mM GSH blocked the oxidative effects of H2O2. Since GSH counteracts the oxidative stress and Gln participates in TCA cycling, their deficiency may affect the redox balance as well as energy production of sperm cells. These findings shed new light on the pathological mechanisms of infertility associated with LAA. Male infertility patients could benefit from GSH supplement by improvement of acrosin activity and other sperm functions.

ACROSIN deficiency causes total fertilization failure in humans by preventing the sperm from penetrating the zona pellucida.

STUDY QUESTION: Does a homozygous nonsense mutation in ACR lead to total fertilization failure (TFF) resulting in male infertility in humans? SUMMARY ANSWER: A novel homozygous nonsense mutation of ACR (c.167G>A, p.Trp56X) was identified in two infertile brothers and shown to cause human TFF. WHAT IS KNOWN ALREADY: ACROSIN, encoded by ACR, is a major acrosomal enzyme expressed only in the acrosome of the sperm head. Inhibition of acrosin prevents sperm penetration of the zona pellucida (ZP) in several species, including humans. Acr-knockout in hamsters causes male infertility with completely blocked fertilization. Of note, there are no reports of ACR mutations associated with TFF in humans. STUDY DESIGN, SIZE, DURATION: Whole-exome sequencing (WES) was used for the identification of pathogenic genes for male factor TFF in eight involved couples. PARTICIPANTS/MATERIALS, SETTING, METHODS: Data from eight infertile couples who had experienced TFF during their IVF or ICSI attempts were collected. Functional assays were used to verify the pathogenicity of the potential genetic factors identified by WES. Subzonal insemination (SUZI) and IVF assays were performed to determine the exact pathogenesis of TFF caused by deficiencies in ACROSIN. MAIN RESULTS AND THE ROLE OF CHANCE: A novel homozygous nonsense mutation in ACR, c.167G>A, p.Trp56X, was identified in two additional primary infertile brothers whose parents were first cousins. This rare mutation caused ACROSIN deficiency and acrosomal ultrastructural defects in the affected sperm. Spermatozoa lacking ACROSIN were unable to penetrate the ZP, rather than hampering sperm binding, disrupting gamete fusion, or preventing oocyte activation. These findings were supported by the fertilization success of SUZI and ICSI attempts, as well as the normal expression of ACTL7A and PLCζ in the mutant sperm, suggesting that ICSI without remedial assisted oocyte activation is an optimal treatment for ARCOSIN-deficient TFF. LIMITATIONS, REASONS FOR CAUTION: The absence of another independent pedigree to support our argument is a limitation of this study. WIDER IMPLICATIONS OF THE FINDINGS: The findings expand our understanding of the genes involved in human TFF, providing information for appropriate genetic counseling and fertility guidance for these patients. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the National Natural Science Foundation of China (grant no. 82201803, 81901541, 82271639, and 32000584), University Synergy Innovation Program of Anhui Province (GXXT-2019-044), and the Nonprofit Central Research Institute Fund of the Chinese Academy of Medical Sciences (grant no. 2019PT310002). The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

Acrosin is essential for sperm penetration through the zona pellucida in hamsters.

During natural fertilization, mammalian spermatozoa must pass through the zona pellucida before reaching the plasma membrane of the oocyte. It is assumed that this step involves partial lysis of the zona by sperm acrosomal enzymes, but there has been no unequivocal evidence to support this view. Here we present evidence that acrosin, an acrosomal serine protease, plays an essential role in sperm penetration of the zona. We generated acrosin-knockout (KO) hamsters, using an in vivo transfection CRISPR/Cas9 system. Homozygous mutant males were completely sterile. Acrosin-KO spermatozoa ascended the female genital tract and reached ovulated oocytes in the oviduct ampulla, but never fertilized them. In vitro fertilization (IVF) experiments revealed that mutant spermatozoa attached to the zona, but failed to penetrate it. When the zona pellucida was removed before IVF, all oocytes were fertilized. This indicates that in hamsters, acrosin plays an indispensable role in allowing fertilizing spermatozoa to penetrate the zona. This study also suggests that the KO hamster system would be a useful model for identifying new gene functions or analyzing human and animal disorders because of its technical facility and reproducibility.

Immature rat testis sustained long-term development using an integrative model.

BACKGROUND: Xenotransplantation has been primarily performed using fresh donor tissue to study testicular development for about 20 years, and whether the cultured tissue would be a suitable donor is unclear. In this study, we combined testicular culture and xenotransplantation into an integrative model and explored whether immature testicular tissue would survive and continue to develop in this model. METHODS: In the new integrative model group, the testes of neonatal rats on postnatal day 8 (PND 8) were cultured for 4 days ex vivo and then were transplanted under the dorsal skin of castrated nude mice. The xenografted testes were resected on the 57th day after xenotransplantation and the testes of rats in the control group were harvested on PND 69. The survival state of testicular tissue was evaluated from morphological and functional perspectives including H&E staining, immunohistochemical staining of 8-OH-dG, immunofluorescence staining, TUNEL assay, ultrastructural study, gene expression and protein analysis. RESULTS: (a) We found that complete spermatogenesis was established in the testes in the new integrative model group. Compared with the control in the same stage, the seminiferous epithelium in some tubules was a bit thinner and there were vacuoles in part of the tubules. Immunofluorescence staining revealed some ACROSIN-positive spermatids were present in seminiferous tubule of xenografted testes. TUNEL detection showed apoptotic cells and most of them were germ cells in the new integrative model group. 8-OH-dG immunohistochemistry showed strongly positive-stained in the seminiferous epithelium after xenotransplantation in comparison with the control group; (b) Compared with the control group, the expressions of FOXA3, DAZL, GFRα1, BOLL, SYCP3, CDC25A, LDHC, CREM and MKI67 in the new integrative model group were significantly elevated (P < 0.05), indicating that the testicular tissue was in an active differentiated and proliferative state; (c) Antioxidant gene detection showed that the expression of Nrf2, Keap1, NQO1 and SOD1 in the new integrative model group was significantly higher than those in the control group (P < 0.05), and DNA methyltransferase gene detection showed that the expression of DNMT3B was significantly elevated as well (P < 0.05). CONCLUSION: The new integrative model could maintain the viability of immature testicular tissue and sustain the long-term survival in vivo with complete spermatogenesis. However, testicular genes expression was altered, vacuolation and thin seminiferous epithelium were still apparent in this model, manifesting that oxidative damage may contribute to the testicular development lesion and it needs further study in order to optimize this model.

[Pricking-reinforcing -reducing therapy improves semen quality and seminal plasma biochemical indexes in patients with varicocele infertility].

OBJECTIVE: To investigate the effect of pricking-reinforcing -reducing therapy (PRRT) on the semen quality and seminal plasma biochemical indexes of varicocele (VC) infertility patients. METHODS: We randomly and equally assigned 160 patients with VC infertility into a PRRT and a control group, the former treated by PRRT and the latter with oral ShengjingCapsules. Before and after treatment, we obtained the semen parameters, sperm morphology, sperm survival rate, sperm acrosin activity, seminal plasma neutral α glucosidase and seminal plasma zinc in the patients and compared them between the two groups. RESULTS: Before treatment, there were no statistically significant differences between the PRRT and control groups in sperm concentration (ï¼»16.81 ± 7.83ï¼½ vs ï¼»16.80 ± 7.54ï¼½ ×106 /ml, P > 0.05), total sperm count (ï¼»42.01 ± 19.57ï¼½ vs ï¼»41.99 ± 18.84ï¼½ ×106, P > 0.05), percentages of progressively motile sperm (PMS) (ï¼»15.37 ± 11.03ï¼½% vs ï¼»14.68 ± 10.27ï¼½%, P > 0.05) and morphologically normal sperm ( MNS) (1.62 ± 1.51ï¼½% vs ï¼»1.62 ± 1.13ï¼½%, P > 0.05), sperm survival rate (ï¼»28.11 ± 18.95ï¼½% vs ï¼»28.23±18.38ï¼½%, P > 0.05) and sperm acrosin activity (ï¼»28.11 ± 14.64ï¼½ vs ï¼»27.19 ± 14.07ï¼½ U/L, P > 0.05). After three months of treatment, all the patients showed evident increases in the above parameters (P < 0.05), even higher in the PRRT than in the control group, more significantly in sperm concentration (ï¼»38.88 ± 30.54ï¼½ vs ï¼»25.60 ± 14.71ï¼½ ×106 /ml, P < 0.05), PMS (ï¼»32.60 ± 12.46ï¼½% vs ï¼»27.67 ± 12.27ï¼½%, P < 0.05) and sperm acrosin activity (ï¼»65.74±31.81ï¼½ vs ï¼»67.94±17.95ï¼½ U/L, P < 0.05), though not significantly in total sperm count (97.20 ± 76.35ï¼½ vs ï¼»88.19 ± 39.56ï¼½ ×106, P > 0.05), MNS (ï¼»2.35 ± 1.83ï¼½% vs ï¼»1.87 ± 1.20ï¼½%, P > 0.05) and sperm survival rate (ï¼»61.44 ± 20.02ï¼½% vs ï¼»59.12 ± 22.48ï¼½%, P > 0.05). Compared with the baseline, after treatment, the patients in the PRRT group also exhibited elevated levels of neutral α-glucosidase (ï¼»14.42 ± 5.90ï¼½ vs ï¼»28.43 ± 19.76ï¼½ U/L, P < 0.05) and seminal plasma zinc (ï¼»2.11 ± 1.22ï¼½ vs ï¼»2.89 ± 1.23ï¼½ mmol/L, P < 0.05), and so did the controls (ï¼»14.44 ± 5.61ï¼½ vs ï¼»26.66 ± 17.69ï¼½ U/L , P < 0.05) and (ï¼»2.09 ± 1.10ï¼½ vs ï¼»2.82±1.08ï¼½ mmol/L, P < 0.05). No statistically significant difference, however, was observed between the two groups after treatment (P > 0.05). CONCLUSION: PRRT can significantly improve semen quality in patients with VC infertility, even more effective than ShengjingCapsules in improving sperm concentration, PMS, sperm survival rate, and sperm acrosin activity, which may be related to its effect of elevating the levels of seminal plasma neutral-α glucosidase and zinc providing sufficient energy for basic sperm metabolism, maturation, energy acquisition and motility.

Limited proteolysis by acrosin affects sperm-binding and mechanical resilience of the mouse zona pellucida.

The encounter of oocyte and sperm is the key event initiating embryonic development in mammals. Crucial functions of this existential interaction are determined by proteolytic enzymes, such as acrosin, carried in the sperm head acrosome, and ovastacin, stored in the oocyte cortical granules. Ovastacin is released upon fertilisation to cleave the zona pellucida, a glycoprotein matrix surrounding the oocyte. This limited proteolysis hardens the oocyte envelope, and thereby provides a definitive block against polyspermy and protects the developing embryo. On the other hand, acrosin, the renowned and most abundant acrosomal protease, has been thought to enable sperm to penetrate the oocyte envelope. Depending on the species, proteolytic cleavage of the zona pellucida by acrosin is either essential or conducive for fertilisation. However, the specific target cleavage sites and the resulting physiological consequences of this proteolysis remained obscure. Here, we treated native mouse zonae pellucidae with active acrosin and identified two cleavage sites in zona pellucida protein 1 (ZP1), five in ZP2 and one in ZP3 by mass spectrometry. Several of these sites are highly conserved in mammals. Remarkably, limited proteolysis by acrosin leads to zona pellucida remodelling rather than degradation. Thus, acrosin affects both sperm binding and mechanical resilience of the zona pellucida, as assessed by microscopy and nanoindentation measurements, respectively. Furthermore, we ascertained potential regulatory effects of acrosin, via activation of latent pro-ovastacin and inactivation of fetuin-B, a tight binding inhibitor of ovastacin. These results offer novel insights into the complex proteolytic network modifying the extracellular matrix of the mouse oocyte, which might apply also to other species.

Effects of Cryopreservation on Acrosin Activity and DNA Damage of Russian Sturgeon (Acipenser gueldenstaedtii) Semen.

BACKGROUND: Cryopreservation of sturgeon sperm can be successful, but there can be a decrease in sperm viability and the reasons are not clear. OBJECTIVE: To investigate variations in the acrosin activity and the DNA integrity of Acipenser gueldenstaedtii semen during cryopreservation at -196ºC. MATERIALS AND METHODS: Fish semen samples were randomly divided into three groups: [1] fresh control; [2] native semen diluted 1:1 with 23.4 mM sucrose + 0.25 mM KCl + 30 mM Tris (pH 8.0) and the addition of 10% methanol as cryoprotectant; and [3] semen without any diluents or cryoprotectants. Acrosin activity and DNA damage (COMET assay) were assessed. RESULTS: The average acrosin activity fell to 61% and 27% of the control for cryoprotected and non-cryoprotected semen after cryopreservation. The differences among the three groups were significant (P<0.05). We also observed that various indexes of DNA damage (L-tail; tail DNA, tail momentum, olive tail momentum) were higher in semen that had been frozen. CONCLUSION: Although cryopreservation of semen induces decreased acrosin activity and increased DNA damage, cryoprotectants can protect the semen during cryopreservation.

Photobiomodulation and gametogenic potential of human Wharton's jelly-derived mesenchymal cells.

Recently, light emitting diode (LED) irradiation has been introduced as a new strategy to enhance proliferation and affect differentiation of stem cells. Human Wharton's jelly-derived mesenchymal (hWJM) cells have unique characteristics that make them an appropriate source of stem cells for use in basic and clinical applications. In this study, we aimed to evaluate the effect of polarized (PL) and non-polarized (NPL) red light irradiation on gametogenic differentiation of hWJM cells in the presence or absence of bone morphogenetic protein 4 (BMP4) and retinoic acid (RA). Exposure of hWJM cells to PL and NPL red LED (625 nm, 1.9 J/cm2) with or without BMP4+RA pre-treatment effectively differentiated them into germ lineage when the gene expression pattern (Fragilis, DAZL, VASA, SCP3 and Acrosin) and protein synthesis (anti-DAZL, anti-VASA, anti-SCP3 and anti-Acrosin antibodies) of the induced cells was evaluated. These data demonstrated that photobiomodulation may be applied for gametogenic differentiation in-vitro.

Mitochondrial functionality modifies human sperm acrosin activity, acrosome reaction capability and chromatin integrity.

STUDY QUESTION: In addition to sperm motility, which major biological characteristics of sperm fertility potential are associated with mitochondrial functionality? SUMMARY ANSWER: Sperm fertilization capacities, including acrosin activity, acrosome reaction (AR) capability and chromatin integrity, are related to the mitochondria functionality as evaluated by the mitochondrial membrane potential (MMP). WHAT IS KNOWN ALREADY: Correlative studies suggest a potential role of sperm MMP in predicting sperm fertilization ability and ensuring sperm motility. However, researches characterizing other determinants of sperm fertility potential according to MMP are lacking. STUDY DESIGN, SIZE, DURATION: The sperm MMP was examined in 627 young college students in the Male Reproductive Health in Chongqing College Students (MARHCS) cohort study in 2014. Among these participants, acrosin activity and chromatin integrity were measured in 378 and 604 subjects, respectively. These two determinants of sperm fertility potential were first compared among high-, moderate- and low-MMP groups in the college population. The effects of MMP collapse caused by carbonyl cyanide 3-chlorophenylhydrazone (CCCP) on acrosin activity, AR, DNA fragmentation, reactive oxygen species (ROS) production, and ATP content in human spermatozoa were evaluated in vitro. PARTICIPANTS/MATERIALS, SETTING, METHODS: The sperm MMP was evaluated by using JC-1 staining, acrosin activity was measured using a N-α-benzoyl-dl-arginine-para-nitroanilide HCl (BAPNA) substrate method, the integrity of chromatin represented by DNA fragmentation index (DFI) was measured by sperm chromatin structure assay (SCSA), AR was evaluated with chlortetracycline staining, and intracellular ROS production was evaluated with dihydroethidium. ATP concentration was determined with luciferase. Measurements were performed by spectrophotometry or flow cytometry. MAIN RESULTS AND THE ROLE OF CHANCE: Nonparametric analysis revealed significantly higher acrosin activity and a lower DFI in subjects with moderate or high MMP compared to those with low MMP. After adjustment for potential confounders, increases of 7.9 and 44.4% in sperm acrosin activity and deceases of 12.0 and 25.2% in the sperm DFI were found in the moderate- and high-MMP groups, respectively. The MMP dissipation induced by CCCP caused significant declines in acrosin activity and AR capacity and increased DFI in human spermatozoa. Moreover, sperm MMP dissipation induced ROS overproduction and decreased ATP content. LIMITATIONS, REASONS FOR CAUTION: We cannot exclude a contribution of leukocytes to ROS production and no size gating was used to exclude these cells from the FACS measurements. No simultaneous live-dead staining was done and a contribution of dead sperm to the MMP and acrosome assays cannot be excluded. WIDER IMPLICATIONS OF THE FINDINGS: Mitochondrial functionality might be necessary to maintain sperm acrosin activity, AR and chromatin integrity. Tests of mitochondrial functionality should be developed and used independently of or in addition to conventional semen parameters in infertility diagnosis or risk-assessment processes. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the Key Program of the National Natural Science Foundation of China (No. 81630087) and the National Natural Science Foundation of China (No. 81703254). None of the authors have any competing interests to declare.

The seminal acrosin-inhibitor ClTI1/SPINK2 is a fertility-associated marker in the chicken.

The seminal plasma is a very complex fluid, which surrounds sperm in semen. It contains numerous proteins including proteases and protease inhibitors that regulate proteolytic processes associated with protein activation and degradation. We previously identified a seminal protein, chicken liver trypsin inhibitor 1 (ClTI-1) over expressed in semen of roosters with high fertility, suggesting a role in male fertility. In the present study, we showed that ClTI-1 gene is actually SPINK2. Using normal healthy adult roosters, we showed that SPINK2 amount in seminal plasma was positively correlated with male fertility in chicken lines with highly contrasted genetic backgrounds (broiler and layer lines). Using affinity chromatography combined to mass spectrometry analysis and kinetic assays, we demonstrated for the first time that two chicken acrosin isoforms (acrosin and acrosin-like proteins) are the physiological serine protease targets of SPINK2 inhibitor. SPINK2 transcript was overexpressed all along the male tract, and the protein was present in the lumen as expected for secreted proteins. Altogether, these data emphasize the role of seminal SPINK2 Kazal-type inhibitor as an important actor of fertility in birds through its inhibitory action on acrosin isoforms proteins.

Freezing of Stallion Semen: in vitro and in vivo Evaluation of Sperm Motility and Acrosin Activity in Frozen-thawed Semen with Addition of Post-diluent Extenders.

BACKGROUND: Post-diluents could potentially increase semen cryotolerance, but remain poorly explored in horses. OBJECTIVE: The aim was to evaluate the efficiency of post-diluents on frozen-thawed semen viability of two stallions (S1-S2). MATERIALS AND METHODS: The cryopreserved semen was thawed at 50°C for 40 seconds. Semen motility and acrosin activity (AA) were determined during the thermo-resistance test (TRT). RESULTS: Progressive motility of S2 semen decreased after 60 and 90 minutes of TRT (TRT60 and TRT90) on the control compared to both post-diluents. The total motility of both S1 and S2 decreased on TRT60 and TRT90 semen control versus both Ringer and Merk post-diluents. The AA on S1 was higher than S2 throughout the TRT. Pregnancy rates after artificial insemination (AI) were similar among post-diluents and stallions. CONCLUSION: Post-diluents do not contribute to predicting frozen-thawed semen fertility or the efficiency of equine AI.

[L-carnitine improves sperm acrosin activity in male infertility patients].

OBJECTIVE: To evaluate the effect of L-carnitine (LC) on low sperm acrosin activity in infertile man. METHODS: A total of 240 male infertility patients with low sperm acrosin activity were randomly assigned to an LC group (n = 180) and a control group (n = 60) to be treated with LC (1g, tid) and vitamin E (VE) capsules (100 mg, tid) respectively, both for 3 months. Based on the results of routine semen analysis, the patients in the experimental group were further divided into oligozoospermia, asthenozoospermia and normozoospermia subgroups. Semen parameters and sperm acrosin activity were examined before and after treatment. RESULTS: Totally, 220 of the patients completed the treatment and follow-up, 163 in the LC medication and 57 in the VE control group. Compared with the baseline, the percentage of progressively motile sperm (PMS) was significantly increased in the LC group after 3 months of treatment (ï¼»32.58 ± 1.13ï¼½% vs ï¼»36.35 ± 1.26ï¼½%, P < 0.05), and so was sperm acrosin activity (ï¼»37.05±0.66ï¼½ vs ï¼»58.61±1.93ï¼½ µIU/106 sperm, P < 0.01). Sperm concentration, PMS and sperm acrosin activity were also improved in the VE control group after treatment, but with no statistically significant difference (P > 0.05). In comparison with pretreatment, remarkable increases were observed after LC medication in sperm concentration in the oligozoospermia subgroup (ï¼»11.27 ± 0.73ï¼½ vs ï¼»21.82 ± 4.21ï¼½ ×106/ml, P < 0.01) and PMS in the asthenozoospermia patients (ï¼»20.61 ± 0.85ï¼½% vs ï¼»29.81 ± 1.88ï¼½%, P < 0.01). And sperm acrosin activity was even higher after treatment in the asthenozoospermia than in the oligozoospermia and normozoospermia subgroups (ï¼»60.85 ± 3.04ï¼½ vs ï¼»56.32 ± 2.86ï¼½ and ï¼»57.09 ± 6.31ï¼½ µIU/106 sperm, P < 0.05). CONCLUSIONS: L-carnitine can effectively elevate sperm acrosin activity in male infertility patients, particularly in those with asthenozoospermia.

A delayed sperm penetration of cumulus layers by disruption of acrosin gene in rats.

Acrosin, the trypsin-like serine protease in the sperm acrosome, was long viewed as a key enzyme required for zona pellucida penetration to fertilize eggs. However, gene disruption experiments in mice surprisingly showed that acrosin-disrupted males were fertile. Thus, the acrosin was considered to be not an essential enzyme for fertilization in mice. However, the involvement of acrosin in fertilization has been suggested in various species such as rat, bull, and pig. Moreover, it has been reported that serine protease (including acrosin) activity in mice is significantly weaker compared to other species, including rats. We analyzed the role of acrosin by disrupting the rat acrosin gene. It was found that, unlike in mice, acrosin was almost the sole source of serine protease in rat spermatozoa. Nevertheless, the acrosin-disrupted males were not infertile. However, the litter size from acrosin-disrupted males was decreased compared to heterozygous mutant rats. Further investigation using an in vitro fertilization system revealed that the acrosin-disrupted spermatozoa possessed an equal ability to penetrate the zona pellucida with wild-type spermatozoa, but the cumulus cell dispersal was slower compared to wild-type and heterozygous spermatozoa. This delay was presumed to be the cause of the small litter size of acrosin-disrupted male rats.

Antigen unmasking enhances visualization efficacy of the oocyte activation factor, phospholipase C zeta, in mammalian sperm.

STUDY QUESTION: Is it possible to improve clinical visualization of phospholipase C zeta (PLCζ) as a diagnostic marker of sperm oocyte activation capacity and male fertility? SUMMARY ANSWER: Poor PLCζ visualization efficacy using current protocols may be due to steric or conformational occlusion of native PLCζ, hindering antibody access, and is significantly enhanced using antigen unmasking/retrieval (AUM) protocols. WHAT IS KNOWN ALREADY: Mammalian oocyte activation is mediated via a series of intracellular calcium (Ca2+) oscillations induced by sperm-specific PLCζ. PLCζ represents not only a potential clinical therapeutic in cases of oocyte activation deficiency but also a diagnostic marker of sperm fertility. However, there are significant concerns surrounding PLCζ antibody specificity and detection protocols. STUDY DESIGN, SIZE DURATION: Two PLCζ polyclonal antibodies, with confirmed PLCζ specificity, were employed in mouse, porcine and human sperm. Experiments evaluated PLCζ visualization efficacy, and whether AUM improved this. Antibodies against two sperm-specific proteins [post-acrosomal WW-binding protein (PAWP) and acrosin] were used as controls. PARTICIPANTS/MATERIALS, SETTING, METHODS: Aldehyde- and methanol-fixed sperm were subject to immunofluorescence analysis following HCl exposure (pH = 0.1-0.5), acid Tyrode's solution exposure (pH = 2.5) or heating in 10 mM sodium citrate solution (pH = 6.0). Fluorescence intensity of at least 300 cells was recorded for each treatment, with three independent repeats. MAIN RESULTS AND THE ROLE OF CHANCE: Despite high specificity for native PLCζ following immunoblotting using epitope-specific polyclonal PLCζ antibodies in mouse, porcine and human sperm, immunofluorescent visualization efficacy was poor. In contrast, sperm markers PAWP and acrosin exhibited relatively impressive results. All methods of AUM on aldehyde-fixed sperm enhanced visualization efficacy for PLCζ compared to visualization efficacy before AUM (P < 0.05 for all AUM interventions), but exerted no significant change upon PAWP or acrosin immunofluorescence following AUM. All methods of AUM enhanced PLCζ visualization efficacy in mouse and human methanol-fixed sperm compared to without AUM (P < 0.05 for all AUM interventions), while no significant change was observed in methanol-fixed porcine sperm before and after. In the absence of aldehyde-induced cross-linkages, such results suggest that poor PLCζ visualization efficacy may be due to steric or conformational occlusion of native PLCζ, hindering antibody access. Importantly, examination of sperm from individual donors revealed that AUM differentially affects observable PLCζ fluorescence, and the proportion of sperm exhibiting detectable PLCζ fluorescence in sperm from different males. LIMITATIONS, REASONS FOR CAUTION: Direct correlation of fertility outcomes with the level of PLCζ in the sperm samples studied was not available. Such analyses would be required in future to determine whether the improved methodology for PLCζ visualization we propose would indeed reflect fertility status. WIDER IMPLICATIONS OF THE FINDINGS: We propose that AUM alters conformational interactions to enhance PLCζ epitope availability and visualization efficacy, supporting prospective application of AUM to reduce misinterpretation in clinical diagnosis of PLCζ-linked male infertility. Our current results suggest that it is perhaps prudent that previous studies investigating links between PLCζ and fertility parameters are re-examined in the context of AUM, and may pave the way for future work to answer significant questions such as how PLCζ appears to be kept in an inactive form in the sperm. LARGE SCALE DATA: Not applicable. STUDY FUNDING/COMPETING INTERESTS: J.K. is supported by a Health Fellowship award from the National Institute for Social Care and Health Research (NISCHR). M.N. is supported by a Marie Curie Intra-European Research Fellowship award. This work was also partly funded by a research grant from Cook Medical Technologies LLC. There are no competing financial interests to declare.

Effects of reduced glutathione on acrosin activity in frozen-thawed boar spermatozoa.

In pigs, acrosin activity in extended semen is correlated with reproductive performance and has recently been identified as a freezability marker. Reduced glutathione (GSH) is known to decrease sperm cryodamage and increase the reproductive performance of frozen-thawed boar spermatozoa. However, the effects of GSH on the acrosin activity of good and poor freezability ejaculates (GFE and PFE, respectively) is yet to be examined. The present study investigated how supplementing cryopreservation media with GSH affected acrosin activity in GFE and PFE, as well as the relationship between acrosin activity and reproductive performance in frozen-thawed boar spermatozoa. In addition, we examined whether the increase in fertility rates and litter sizes observed after the addition of 2mM GSH to cryopreservation extenders was related to acrosin activity. Supplementing freezing media with 2mM GSH partially counteracted the cryopreservation-related decrease in acrosin activity in GFE but not PFE. Acrosin activity was found to be significantly correlated with in vivo reproductive performance of frozen-thawed boar semen. In conclusion, the effects of adding GSH to freezing extenders on the acrosin activity of frozen-thawed boar spermatozoa rely on the intrinsic freezability of the ejaculate. Furthermore, the maintenance of proper acrosin activity could contribute to the increase in reproductive performance mediated by GSH.

Cryopreservation of adult cervid testes.

Several species of cervids are currently classified as threatened or endangered due to a rapid decline in their populations. Sperm cryopreservation, in association with assisted reproductive technologies, can find application for the conservation of endangered cervids. In cases of unsuccessful sperm retrieval through other means prior to the death of the animal, adult testis is the only source of sperm. Recovery of viable sperm from adult testes depends on the effective preservation of testicular tissues through optimization of cryopreservation protocols. The present study evaluated combinations of 10% dimethyl sulfoxide (DMSO) with 0% or 80% fetal bovine serum (FBS) and 20% DMSO with 0 or 20% FBS for the cryopreservation of testicular tissues of three adult cervids using uncontrolled slow freezing protocol. The cryopreserved testis was compared to chilled tissue without cryoprotectants. Results revealed that testicular tissues of barking deer cryopreserved in 20% DMSO (D20) had all the analyzed 7 parameters (number of TNP1-, PRM2 and acrosin-expressing cells/tubule and, the number of viable, morphologically normal, acrosome intact, Annexin V-negative sperm) comparable to the chilled testis. However, testicular tissues of sambhar and hog deer cryopreserved only in D20S20 had 5 of 7 parameters comparable to the chilled testis. In conclusion, D20 is acceptable for cryopreservation of barking deer and D20S20 for sambar and hog deer testes.

[Value of sperm acrosin activity detection in selecting the method of assisted reproduction for patients with unexplained infertility].

OBJECTIVE: To investigate the clinical significance of sperm acrosin activity detection in selecting the method of assisted reproduction for patients with unexplained infertility (UI). METHODS: This retrospective study included 49 UI couples treated by IVFET (49 cycles) after three failures in intrauterine insemination (IUI) and another 95 couples with uterine tube obstruction (UTO) treated by IVF (131 cycles). We analyzed the laboratory data, clinical outcomes and sperm acrosin activity in the two groups of patients. According to the level of sperm acrosin activity of the males, we further divided the UI patients into two subgroups, a < 36 IU/106 sperm group (20 cycles) and a ≥36 IU/106 sperm group (29 cycles), and compared the fertilization rates between the two groups. RESULTS: Compared with UI couples treated by IVFET, the UTO couples treated by IVF had a significantly lower rate of fertilization (67.0% vs 76.4%, P < 0.05) and a higher rate of remedial intracytoplasmic sperm injection (ICSI) (20.4% vs 6.1%, P < 0.05), but showed no statistically significant differences in the rates of MII oocytes, available embryos, highquality embryos, implantation, and clinical pregnancy from the latter group (P >0.05). The sperm acrosin activity was remarkably lower in the UI than in the UTO patients (36.03 vs 61.98 IU/106, P < 0.01), and so was the fertilization rate in the < 36 IU/106 than in the ≥36 IU/106 sperm subgroup (47.7% vs 80.3%, P < 0.01). CONCLUSIONS: The low fertilization rate caused by decreased sperm acrosin activity may be the main cause of infertility and the potential factor of UI. When sperm acrosin activity is < 36 IU/106 sperm, IVF plus shortterm fertilization by remedial ICSI should be preferred to IUI.

Acrosome Reaction as a Preparation for Gamete Fusion.

The acrosome reaction (AR) is a universal requisite for sperm-egg fusion. However, whereas through the animal kingdom fusion of spermatozoa with the egg plasma membrane occurs via the inner acrosomal membrane exposed after the AR, in eutherian mammals, gamete fusion takes place through a specialized region of the acrosome known as the equatorial segment (ES) which becomes fusogenic only after the AR is completed. This chapter focuses on the different molecular mechanisms involved in the acquisition of the fusogenicity of the ES after the AR. We provide an update of the knowledge about the proteins proposed to have a role in this process either by modifying cytoskeletal and/or membrane molecules or by relocalizing to the ES after the AR to subsequently participate in gamete fusion.