Improved viability and fertility of frozen-thawed dog sperm using adipose-derived mesenchymal stem cells

Effect of Conditioned Medium from Human Adipose-Derived Mesenchymal Stem Cells on Human Sperm Quality During Cryopreservation

The cryopreservation procedure decreases sperm quality, causing certain changes at structural and molecular levels affecting fertilizing ability. We aimed to investigate the impacts of human adipose-derived mesenchymal stem cells (HAd-MSCs) conditioned medium (CM) on the protection of human sperm from cryoinjury. Thirty normal semen specimens were evaluated in this study. Each specimen was separated into six groups and enhanced with varying concentrations of human Ad-MSCs-CM (0, 10, 30, 50, 70, and 100%). Sperm motility, viability, morphology, apoptosis, mitochondrial potential, and lipid peroxidation, and DNA fragmentation were evaluated before freezing and after thawing. The results showed that the total motility was preserved in 10% human Ad-MSCs-CM group. Also, DNA fragmentation was significantly lower in 10% compared to 0% human Ad-MSCs-CM (63.62 ± 17.72% vs.76.46 ± 4.87%, respectively, P < 0.004). Human Ad-MSCs-CM in groups of 10, 30, 50, and 70% reduced lipid peroxidation. The normal sperm morphology rate, mitochondrial membrane potential, and apoptosis showed no significant differences across various groups. It seems that human Ad-MSCs-CM can protect the sperm parameters during the cryopreservation by decreasing cryoinjury.

Effects of extracellular vesicles derived from steroids-primed oviductal epithelial cells on porcine in vitro embryonic development

Extracellular vesicles (EVs) play an active role in regulating different physiological events, however, endocrine control of EVs cargo contents remain poorly understood. In this study, we aimed to isolate EVs from the porcine oviductal epithelial cells (POECs) that were primed with steroid hormones including estradiol (E2) and progesterone (P4), mimicking the in vivo conditions of the reproductive cycle and studied their effects on in vitro produced embryonic development. For this purpose, POECs were treated either with 0 concentration (control) or two different combinations of E2 and P4 including 50 pg/mL E2 + 0.5 ng/mL P4 (group H1), and 10 pg/mL E2 + 35 ng/mL P4 (group H2). Embryos were prepared after in vitro maturation either by parthenogenetic activation or somatic cell nuclear transfer (SCNT) technique. Treating parthenogenetic embryo with EVs, led a significantly higher rate of the blastocyst formation in the group supplemented with each EVs, compared to the control group. In addition, TUNEL assay and gene expression level analysis revealed that apoptosis was significantly reduced in the H2 EVs group. Furthermore, EVs from hormone-primed POECs improved the formation rate of porcine SCNT embryos compared to the control group. While in each EVs supplemented group (control EVs, H1 EVs, H2 EVs), the expression of cell reprogramming-related genes in cloned embryos showed a tendency of increase, the effect was stronger in H1 EVs and H2 EVs. In conclusion, EVs derived from POECs cultured in hormonal conditions simulating the in vivo environment had a positive effect on porcine blastocysts formation, which will likely facilitate in the production of cloned embryos.

Human umbilical cord mesenchymal stem cells (hUC-MSCs) alleviate paclitaxel-induced spermatogenesis defects and maintain male fertility

Chemotherapeutic drugs can cause reproductive damage by affecting sperm quality and other aspects of male fertility. Stem cells are thought to alleviate the damage caused by chemotherapy drugs and to play roles in reproductive protection and treatment. This study aimed to explore the effects of human umbilical cord mesenchymal stem cells (hUC-MSCs) on alleviating paclitaxel (PTX)-induced spermatogenesis and male fertility defects. An in vivo PTX-induced mice model was constructed to evaluate the reproductive toxicity and protective roles of hUC-MSCs in male fertility improvement. A 14 day PTX treatment regimen significantly attenuated mice spermatogenesis and sperm quality, including affecting spermatogenesis, reducing sperm counts, and decreasing sperm motility. hUC-MSCs treatment could significantly improve sperm functional indicators. Mating experiments with normal female mice and examination of embryo development at 7.5 days post-coitum (dpc) showed that hUC-MSCs restored male mouse fertility that was reduced by PTX. In IVF experiments, PTX impaired sperm fertility and blastocyst development, but hUC-MSCs treatment rescued these indicators. hUC-MSCs' protective role was also displayed through the increased expression of the fertility-related proteins HSPA2 and HSPA4L in testes with decreased expression in the PTX-treated group. These changes might be related to the PTX-induced decreases in expression of the germ cell proliferation protein PCNA and the meiosis proteins SYCP3, MLH1, and STRA8, which were restored after hUC-MSCs treatment. In the PTX-treated group, the expression of testicular antioxidant proteins SIRT1, NRF2, CAT, SOD1, and PRDX6 was significantly decreased, but hUC-MSCs could maintain these expressions and reverse PTX-related increases in BAX/BCL2 ratios. hUC-MSCs may be a promising agent with antioxidant and anti-apoptosis characteristics that can maintain sperm quality following chemotherapy treatment.

Protective effects of human amniotic membrane derived mesenchymal stem cells (hAMSCs) secreted factors on mouse spermatogenesis and sperm chromatin condensation following unilateral testicular torsion

Testicular torsion is considered a urological disorder that requires immediate detorsion surgery. Ischemia/reperfusion (I/R) injury after testicular torsion detorsion causes of drastic impairment of spermatogenesis and infertility. Cell-free-based approaches seem to be a promising strategy to prevent I/R injury, they have more stable biological properties, and they contain paracrine factors of mesenchymal stem cells. The purpose of this study was to evaluate the protective effects of human amniotic membrane derived mesenchymal stem cells (hAMSCs) secreted factors on mouse sperm chromatin condensation and spermatogenesis improvement after I/R injury. hAMSCs were isolated and characterized by RT- PCR and flow cytometry, preparation of hAMSCs secreted factors was performed. Forty male mice were randomly divided into 4 groups: sham-operated, torsion detorsion, torsion detorsion+ intratesticular injection of DMEM/F-12, and torsion detorsion+ intratesticular injection of hAMSCs secreted factors. After one cycle of spermatogenesis, the mean number of germ cells, Sertoli, Leydig, myoid as well as tubular parameters, Johnson score, and spermatogenesis indexes were evaluated by H& E and PAS stainings. Sperm chromatin condensation and relative expression of c-kit and prm 1 genes were assessed by aniline blue staining and real-time PCR, respectively. The mean number of spermatogenic cells, Leydig, Myoid, Sertoli, spermatogenesis parameters, Johnson score, as well as germinal epithelial height and diameters of seminiferous tubules decreased significantly after I/R injury. The thickness of basement membrane and percentage of sperm with excessive histone significantly increased, while the relative expression of c-kit and prm 1 significantly decreased in torsion detorsion group (p<0.001). hAMSCs secreted factors remarkably restored normal sperm chromatin condensation, spermatogenesis parameters and histomorphometric organization of seminiferous tubules via intratesticular injection (p<0.001). Thus, hAMSCs secreted factors may potentially salvage torsion-detorsion-induced infertility.

Adipose and amnion-derived mesenchymal stem cells: Extracellular vesicles characterization and implication for reproductive biotechnology

The stem cell-based research for reproductive biotechnology has been widely studied and shows promise for repairing defective tissue or degenerated cells to treat different diseases. The adipose tissue and amniotic membrane have awakened great interest in regenerative medicine and arises as a promising source of mesenchymal stem cells. Both types, adipose and amniotic derived mesenchymal stem cells (AMSCs) are multipotent cells with an enhanced ability to differentiate into multiple lineages.. We aimed to evaluate the effect of basal supplementation of exosomes in cell cultures with canine amniotic mesenchymal stem cells (MSCs). Mesenchymal stem cells derived from canine amniotic and adipose tissue were isolated and cultured performing cell passages until 80-90% confluence was reached. The growth curve was determined and peak cell growth was observed in the second passage. The cells were then characterized and differentiated into adipogenic, chondrogenic and osteogenic lineages. Extracellular vesicles from amnion were isolated using an ultracentrifugation protocol and characterized by nanosight analysis. To evaluate their ability to improve cellular viability in naturally inefficient passages, exosomes were co-cultures to the MSC cells. The results showed a 15-20% increase in the expansion rate of cultures supplemented with vesicles extracted in the first and second passages when compared to the control group. Statistical analysis using the Dunnett test (p ≤ 0.05) corroborated this result, showing a positive correlation between supplementation and expansion rate. These results indicate not only the importance of exosomes in the cell communication process but also the feasibility of the culture supplementation protocol for therapeutic purposes. The potential of the AMSCs for reproductive biotechnology is undoubted, however, their application to repair reproductive disorders and the involved mechanisms remain elusive. The strategies to enable the Adipose Stem Cells and AMSCs application in reproductive biotechnology and optimize their use for tissue regeneration open new venues using exosomes interactions.

Oviduct Epithelial Cell-Derived Extracellular Vesicles Improve Porcine Trophoblast Outgrowth

Porcine species have a great impact on studies on biomaterial production, organ transplantation and the development of biomedical models. The low efficiency of in vitro-produced embryos to derive embryonic stem cells has made achieving this goal a challenge. The fallopian tube plays an important role in the development of embryos. Extracellular vesicles (EVs) secreted by oviductal epithelial cells play an important role in the epigenetic regulation of embryo development. We used artificially isolated oviductal epithelial cells and EVs. In this study, oviductal epithelial cell (OEC) EVs were isolated and characterized through transmission electron microscopy, nanoparticles tracking analysis, western blotting and proteomics. We found that embryo development and blastocyst formation rate was significantly increased (14.3% ± 0.6% vs. 6.0% ± 0.6%) after OEC EVs treatment. According to our data, the inner cell mass (ICM)/trophectoderm (TE) ratio of the embryonic cell number increased significantly after OEC EVs treatment (43.7% ± 2.3% vs. 28.4% ± 2.1%). Meanwhile, the attachment ability of embryos treated with OEV EVs was significantly improved (43.5% ± 2.1% vs. 29.2% ± 2.5%, respectively). Using quantitative polymerase chain reaction (qPCR), we found that the expression of reprogramming genes (POU5F1, SOX2, NANOG, KLF4 and c-Myc) and implantation-related genes (VIM, KRT8, TEAD4 and CDX2) significantly increased in OEC EV-treated embryos. We report that OEC EV treatment can improve the development and implantation abilities of embryos.

Assisted reproductive techniques for canines: preservation of genetic material in domestic dogs

Assisted reproductive techniques (ARTs), such as artificial insemination, in vitro fertilization, and cryopreservation of gametes/zygotes, have been developed to improve breeding and reproduction of livestock and for the treatment of human infertility. Their widespread use has contributed to improvements in human health and welfare. However, in dogs, only artificial insemination using frozen semen is readily available as an ART to improve breeding and control genetic diversity. A recent priority in sperm cryopreservation is the development of alternatives to egg yolk, which is widely used as a component of the sperm extender. Egg yolk can vary in composition among batches and is prone to contamination by animal pathogens. The latter can be a problem for international exchange of cryopreserved semen. Low-density lipoprotein and skim milk are promising candidates for use as extenders, to ensure fertility after artificial insemination. Although not tested for its effects on fertility following artificial insemination, polyvinyl alcohol may also be a useful alternative to egg yolk as an extender. The development of cryopreservation techniques for canine embryos lags behind that for other mammals, including humans. However, given the success of non-surgical embryo transfer in 2011, studies have sought to refine this approach for practical use. Research on sperm cryopreservation has yielded satisfactory results. However, investigation of other approaches, such as cryopreservation of oocytes and gonadal tissues, remains insufficient. Techniques for the efficient induction of estrus may aid in the development of successful canine ARTs.

The Role of Stem Cells and Their Derived Extracellular Vesicles in Restoring Female and Male Fertility

Infertility is a globally recognized issue caused by different reproductive disorders. To date, various therapeutic approaches to restore fertility have been attempted including etiology-specific medication, hormonal therapies, surgical excisions, and assisted reproductive technologies. Although these approaches produce results, however, fertility restoration is not achieved in all cases. Advances in using stem cell (SC) therapy hold a great promise for treating infertile patients due to their abilities to self-renew, differentiate, and produce different paracrine factors to regenerate the damaged or injured cells and replenish the affected germ cells. Furthermore, SCs secrete extracellular vesicles (EVs) containing biologically active molecules including nucleic acids, lipids, and proteins. EVs are involved in various physiological and pathological processes and show promising non-cellular therapeutic uses to combat infertility. Several studies have indicated that SCs and/or their derived EVs transplantation plays a crucial role in the regeneration of different segments of the reproductive system, oocyte production, and initiation of sperm production. However, available evidence triggers the need to testify the efficacy of SC transplantation or EVs injection in resolving the infertility issues of the human population. In this review, we highlight the recent literature covering the issues of infertility in females and males, with a special focus on the possible treatments by stem cells or their derived EVs.

Overview on the Antioxidants, Egg Yolk Alternatives, and Mesenchymal Stem Cells and Derivatives Used in Canine Sperm Cryopreservation

Sperm cryopreservation is a widely used assisted reproductive technology for canine species. The long-term storage of dog sperm is effective for the breeding of dogs living far apart, scheduling the time of artificial insemination that suits the female, and preventing diseases of the reproductive tract. However, spermatozoa functions are impaired during the freeze-thaw processes, which may decrease reproductive performance. Numerous attempts have been made to restore such impairments, including the use of cryoprotectants to prevent the damage caused by ice crystal formation, and supplementation of antioxidants to reduce reactive oxygen species generation due to osmotic stress during the procedure. Egg yolk derivatives, antioxidants, and, more recently, mesenchymal stem cells (MSCs) and their derivatives have been proposed in this research field. This review article will summarize the current literature available on the topic.

Antioxidant and antiapoptotic paracrine effects of mesenchymal stem cells on spermatogenic arrest in oligospermia rat model

BACKGROUND

Oligospermia is one of the common causative factors of male infertility. Some medical and hormonal therapy for male infertility is typically with unsatisfactory outcome. Stem cell therapy has become a new therapeutic strategy for restoring function in addition to inducing proliferation and differentiation of malfunctioning germ cells. This work aims at investigating the potential ability of BM-MSCs to repair the spermatogenic arrest in oligospermic rat model.

METHODS

In this work, a rat model of oligospermia was induced using two intraperitoneal injections of busulfan (15 mg/kg) with two weeks interval. Rats were divided into (i) donor group [source of the bone marrow mesenchymal stem cells (BM-MSCs) that were labelled and transfected with green fluorescent protein (GFP)] and (ii) experimental groups that were subdivided into: GpI (control), GpII (spermatogenic arrest model), GpIII (untreated rats), and GpIV (BM-MSCs treated rats). Estimation of the testicular weight, sperm count and motility % were performed. Histological and immunohistochemical staining for inducible nitric oxide synthase (iNOS) and caspase-3 (Cas-3) were conducted. Besides, the level of the testicular malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α) and testicular testosterone were estimated by ELISA.

RESULTS

Oligospermic rats illustrated hypospermatogenesis of the seminiferous tubule with spermatocyte and spermatid arrest, focal thickening of the basement membrane and significant increase in germ cells apoptosis and testicular oxidative stress. Compared with the control, MDA and TNF-α were markedly elevated with marked suppression of the testicular testosterone. Intra-testicular injection of BM-MSCs substantially ameliorated these changes and effectively improved the sperm count and motility %.

CONCLUSIONS

BM-MSCs improved the induced-spermatogenic arrest in the rat model mainly through anti-apoptotic and antioxidant paracrine effects.

Resveratrol supplementation into extender protects against cryodamage in dog post-thaw sperm

Antioxidants have multiple protective roles in a variety of cells and thus can be used to protect sperm against cryo-damage during freezing, which affects fertility. The antioxidant resveratrol (3,5,4-trihydroxytrans-stilbene; RSV) has been reported to protect the animal sperm during cryopreservation, including human sperm. In this study, we assessed the protective effects of RSV supplementation on dog sperm cryopreservation. Semen was collected from four dogs and the effect of different concentrations of RSV (0, 100, 200, and 400 µM) on post-thaw sperm quality was examined. After thawing, sperm motility was assessed using computer-aided sperm analysis, and the structural integrity of the plasma membrane, acrosome, and chromatin was examined. In addition, their mitochondrial activity and gene expression were also assessed. Dog sperm cryopreserved with 200 µM RSV showed significant improvement in post-thaw sperm motility and viability compared with that of the control group (P<0.05). Moreover, RSV-supplemented samples showed significantly higher numbers of sperm with an intact plasma membrane, active mitochondria, and structural integrity of acrosomes and chromatin than that of control samples (P<0.05). Furthermore, gene expression showed that RSV supplemented samples showed lower expression of pro-apoptotic (BAX), reactive oxygen species (ROS) modulator oxidative stress-related (ROMO1) and 8-oxoguanine DNA glycosylase 1 (OGG1) whereas higher expression levels of anti‐apoptotic (BCL2), protamine-2 (PRM2), protamine-3 (PRM3) and sperm acrosome‐associated 3 (SPACA3) genes than control. Our results suggest that RSV, at its optimum concentration, can be efficiently used as an antioxidant in the cryopreservation of dog sperm.

Semen evaluation: methodological advancements in sperm quality-specific fertility assessment - A review

Assessment of male fertility is based on the evaluation of sperm. Semen evaluation measures various sperm quality parameters as fertility indicators. However, semen evaluation has limitations, and it requires the advancement and application of strict quality control methods to interpret the results. This article reviews the recent advances in evaluating various sperm-specific quality characteristics and methodologies, with the help of different assays to assess sperm-fertility status. Sperm evaluation methods that include conventional microscopic methods, computer-assisted sperm analyzers (CASA), and flow cytometric analysis, provide precise information related to sperm morphology and function. Moreover, profiling fertility-related biomarkers in sperm or seminal plasma can be helpful in predicting fertility. Identification of different sperm proteins and diagnosis of DNA damage has positively contributed to the existing pool of knowledge about sperm physiology and molecular anomalies associated with different infertility issues in males. Advances in methods and sperm-specific evaluation has subsequently resulted in a better understanding of sperm biology that has improved the diagnosis and clinical management of male factor infertility. Accurate sperm evaluation is of paramount importance in the application of artificial insemination and assisted reproductive technology. However, no single test can precisely determine fertility; the selection of an appropriate test or a set of tests and parameters is required to accurately determine the fertility of specific animal species. Therefore, a need to further calibrate the CASA and advance the gene expression tests is recommended for faster and field-level applications.

Conditioned Medium from Canine Amniotic Membrane-Derived Mesenchymal Stem Cells Improved Dog Sperm Post-Thaw Quality-Related Parameters

Simple Summary

Mesenchymal stem cells and their derivatives are used in clinical studies for their anti-apoptotic, anti-oxidant, immunomodulatory, and regenerative properties. Their use in reproductive medicine is increasing as they have been proved to be beneficial for infertility treatment. Mesenchymal stem cells can secrete factors that influence biological processes in target tissues or cells; these factors are either directly secreted by the cells or mediated through their derivatives. Although the amniotic membrane is easy to obtain and is a good source of stem cells, clinical trials using amniotic membrane-derived mesenchymal stem cells are still uncommon, especially in reproductive medicine or artificial reproductive technologies. The objective of the present study was to demonstrate the effects of conditioned medium prepared from amniotic membrane-derived stem cells on dog sperm cryopreservation. Our results showed that 10% of the conditioned medium enhanced the quality-related parameters of frozen–thawed sperm cells because of the presence of antioxidants and growth factors in the medium, which probably protected spermatozoa during the freeze–thaw process. These results suggest that conditioned media prepared from amniotic membrane-derived mesenchymal stem cells might have clinical applications in assisted reproductive technologies.

Abstract

This study investigated the effects of conditioned medium (CM) from canine amniotic membrane-derived MSCs (cAMSCs) on dog sperm cryopreservation. For this purpose, flow cytometry analysis was performed to characterize cAMSCs. The CM prepared from cAMSCs was subjected to proteomic analysis for the identification of proteins present in the medium. Sperm samples were treated with freezing medium supplemented with 0%, 5%, 10%, and 15% of the CM, and kinetic parameters were evaluated after 4–6 h of chilling at 4 °C to select the best concentration before proceeding to cryopreservation. Quality-related parameters of frozen–thawed sperm were investigated, including motility; kinetic parameters; viability; integrity of the plasma membrane, chromatin, and acrosome; and mitochondrial activity. The results showed that 10% of the CM significantly enhanced motility, viability, mitochondrial activity, and membrane integrity (p < 0.05); however, the analysis of chromatin and acrosome integrity showed no significant differences between the treatment and control groups. Therefore, we concluded that the addition of 10% CM derived from cAMSC in the freezing medium protected dog sperm during the cryopreservation process.