The effects of poly L-lactic acid nanofiber scaffold on mouse spermatogonial stem cell culture

Identification and Manipulation of Spermatogonial Stem Cells with the Aim of Inducing Spermatogenesis in Vitro

Assisted reproduction techniques for infertile men with non-obstructive azoospermia require a sufficient number of functional germ cells produced in vitro. Understanding the mechanisms that allow the resumption of spermatogenesis outside the testicular environment is crucial for fertility preservation in these patients. A review of the literature was conducted using databases such as PubMed, Scopus and Web of Science, with keywords including "spermatogonial stem cell," "germ cells," "male factor infertility," and "enrichment and propagation of SSCs in vitro." Currently, two models-"in vivo" and "in vitro"-have been developed for producing haploid germ cells. The "in vivo" models include spermatogonial stem cell transplantation and testicular xenograft techniques. In contrast, the "in vitro" models consist of conventional culture systems, organ culture, and three-dimensional culture systems, all designed to induce spermatogenesis in vitro. These culture systems enable the simulation of the seminiferous epithelium in vitro, which facilitates better regulation of cell-signaling pathways that control the self-renewal and differentiation of SSCs. This review provides up-to-date information on the organization of SSCs, focusing on the identification, proliferation, and differentiation of spermatogonia in vitro.

In vivo and in vitro sperm production: an overview of the challenges and advances in male fertility restoration

Male infertility can be caused by genetic anomalies, endocrine disorders, inflammation, and exposure to toxic chemicals or gonadotoxic treatments. Therefore, several recent studies have concentrated on the preservation and restoration of fertility to enhance the quality of life for affected individuals. It is currently recommended to biobank the tissue extracted from testicular biopsies to provide a later source of spermatogonial stem cells (SSCs). Another successful approach has been the in vitro production of haploid male germ cells. The capacity of SSCs to transform into sperm, as in testicular tissue transplantation, SSC therapy, and in vitro or ex vivo spermatogenesis, makes them ideal candidates for in vivo fertility restoration. The transplantation of SSCs or testicular tissue to regenerate spermatogenesis and create embryos has been achieved in nonhuman mammal species. Although the outcomes of human trials have yet to be released, this method may soon be approved for clinical use in humans. Furthermore, regenerative medicine techniques that develop tissue or cells on organic or synthetic scaffolds enriched with bioactive molecules have also gained traction. All of these methods are now in different stages of experimentation and clinical trials. However, thanks to rigorous studies on the safety and effectiveness of SSC-based reproductive treatments, some of these techniques may be clinically available in upcoming decades.

Tissue engineering studies in male infertility disorder

Infertility is an important issue among couples worldwide which is caused by a variety of complex diseases. Male infertility is a problem in 7% of all men. In vitro spermatogenesis (IVS) is the experimental approach that has been developed for mimicking seminiferous tubules-like functional structures in vitro. Currently, various researchers are interested in finding and developing a microenvironmental condition or a bioartificial testis applied for fertility restoration via gamete production in vitro. The tissue engineering (TE) has developed new approaches to treat male fertility preservation through development of functional male germ cells. This makes TE a possible future strategy for restoration of male fertility. Although 3D culture systems supply the perception of the effect of cellular interactions in the process of spermatogenesis, formation of a native gradient of autocrine/paracrine factors in 3D culture systems have not been considered. These results collectively suggest that maintaining the microenvironment of testicular cells even in the form of a 3D-culture system is crucial in achieving spermatogenesis ex vivo. It is also possible to engineer the testicular structures using biomaterials to provide a supporting scaffold for somatic and stem cells. The insemination of these cells with GFs is possible for temporally and spatially adjusted release to mimic the microenvironment of the in situ seminiferous epithelium. This review focuses on recent studies and advances in the application of TE strategies to cell-tissue culture on synthetic or natural scaffolds supplemented with growth factors.

Advancing bovine in vitro fertilization through 3D printing: the effect of the 3D printed materials

Nowadays there is an increasing demand for assisted reproductive technologies due to the growth of infertility problems. Naturally, fertilization occurs in the oviduct, where the oviductal epithelial cells (OECs) secrete many molecules that affect the embryo's metabolism and protect it from oxidative stress. When the OECs are grown in 3D culture systems, they maintain a great part of their functional characteristics, making them an excellent model for in vitro fertilization (IVF) studies. In this work, we aimed to evaluate the suitability of different 3D-printing processes in conjunction with the corresponding set of commercially available biomaterials: extrusion-based processing using polylactic acid (PLA) and polycaprolactone (PCL) and stereolithography or digital-light processing using polyethylene-glycol-diacrylate (PEGDA) with different stiffness (PEGDA500, PEGDA200, PEGDA PhotoInk). All the 3D-printed scaffolds were used to support IVF process in a bovine embryo assay. Following fertilization, embryo development and quality were assessed in terms of cleavage, blastocyst rate at days 7 and 8, total cell number (TCN), inner cell mass/trophectoderm ratio (ICN/TE), and apoptotic cell ratio (ACR). We found a detrimental effect on cleavage and blastocyst rates when the IVF was performed on any medium conditioned by most of the materials available for digital-light processing (PEGDA200, PEGDA500). The observed negative effect could be possibly due to some leaked compound used to print and stabilize the scaffolds, which was not so evident however with PEGDA PhotoInk. On the other hand, all the extrusion-based processable materials did not cause any detrimental effect on cleavage or blastocyst rates. The principal component analysis reveals that embryos produced in presence of 3D-printed scaffolds produced via extrusion exhibit the highest similarity with the control embryos considering cleavage, blastocyst rates, TCN, ICN/TE and ACR per embryo. Conversely, all the photo-cross linkable materials or medium conditioned by PLA, lead to the highest dissimilarities. Since the use of PCL scaffolds, as well as its conditioned medium, bring to embryos that are more similar to the control group. Our results suggest that extrusion-based 3D printing of PCL could be the best option to be used for new IVF devices, possibly including the support of OECs, to enhance bovine embryo development.

Biomaterials for Testicular Bioengineering: How far have we come and where do we have to go?

Traditional therapeutic interventions aim to restore male fertile potential or preserve sperm viability in severe cases, such as semen cryopreservation, testicular tissue, germ cell transplantation and testicular graft. However, these techniques demonstrate several methodological, clinical, and biological limitations, that impact in their results. In this scenario, reproductive medicine has sought biotechnological alternatives applied for infertility treatment, or to improve gamete preservation and thus increase reproductive rates in vitro and in vivo. One of the main approaches employed is the biomimetic testicular tissue reconstruction, which uses tissue-engineering principles and methodologies. This strategy pursues to mimic the testicular microenvironment, simulating physiological conditions. Such approach allows male gametes maintenance in culture or produce viable grafts that can be transplanted and restore reproductive functions. In this context, the application of several biomaterials have been proposed to be used in artificial biological systems. From synthetic polymers to decellularized matrixes, each biomaterial has advantages and disadvantages regarding its application in cell culture and tissue reconstruction. Therefore, the present review aims to list the progress that has been made and the continued challenges facing testicular regenerative medicine and the preservation of male reproductive capacity, based on the development of tissue bioengineering approaches for testicular tissue microenvironment reconstruction.

Genetic and Epigenetic Evaluation of Human Spermatogonial Stem Cells Isolated by MACS in Different Two and Three-Dimensional Culture Systems

<strong>Objective: </strong>Epigenetic and genetic changes have important roles in stem cell achievements. Accordingly, the aim of this<br />study is the evaluation of the epigenetic and genetic alterations of different culture systems, considering their efficacy in<br />propagating human spermatogonial stem cells isolated by magnetic-activated cell sorting (MACS).<br /><strong>Materials and Methods:</strong> In this experimental study, obstructive azoospermia (OA) patient-derived spermatogonial cells were divided into two groups. The MACS enriched and non-enriched spermatogonial stem cells (SSCs) were cultured in the control and treated groups; co-culture of SSCs with Sertoli cells of men with OA, co-culture of SSCs with healthy Sertoli cells of fertile men, the culture of SSCs on PLA nanofiber and culture of testicular cell suspension. Gene-specific methylation by MSP, expression of pluripotency (NANOG, C-MYC and OCT-4), and germ cells specific genes (Integrin α6, Integrin β1, PLZF) evaluated. Cultured SSCs from the optimized group were transplanted into the recipient azoospermic mouse.<br /><strong>Results:</strong> The use of MACS for the purification of human stem cells was effective at about 69% with the culture of the testicular suspension, being the best culture system. Upon purification, the germ-specific gene expression was significantly higher in testicular cell suspension and treated groups (P≤0.05). During the culture time, gene-specific methylation patterns of the examined genes did not show any changes. Our data from transplantation indicated the homing of the donor-derived cells and the presence of human functional sperm.<br /><strong>Conclusion:</strong> Our in vivo and in vitro results confirmed that culture of testicular cell suspension and selection of<br />spermatogonial cells could be effective ways for purification and enrichment of the functional human spermatogonial cells. The epigenetic patterns showed that the specific methylation of the evaluated genes at this stage remained constant with no alteration throughout the entire culture systems over time.

Mechanosensitive Non-Coding RNAs in Osteogenesis of Mesenchymal Stem Cells

In bone tissue engineering, tailored biomaterials mimicking mesenchymal stem cells (MSCs) niche could regulate cell behavior and fate decision. The mechanisms, however, remain obscure. Recently, increasing evidence has shown that non-coding RNAs (ncRNAs) are critical modulators of the mechano-induced MSCs’ responses. Mechanosensitive ncRNAs could convert various physical forces into biochemical signals, and orchestrate signaling networks that regulate the osteogenic differentiation of MSCs in their unique microenvironment. In this review, we focus on the mechanosensitive ncRNAs which could interpret mechanical stimuli during the osteogenesis of MSCs, summarize the signaling pathway networks by which these ncRNAs drive MSCs fate, and point out the limitations and the areas waiting for further exploration.

Optimization of decellularized human placental macroporous scaffolds for spermatogonial stem cells homing

Decellularized scaffolds have been found to be excellent platforms for tissue engineering applications. The attempts are still being made to optimize a decellularization protocol with successful removal of the cells with minimal damages to extracellular matrix components. We examined twelve decellularization procedures using different concentrations of Sodium dodecyl sulfate and Triton X-100 (alone or in combination), and incubation time points of 15 or 30 min. Then, the potential of the decellularized scaffold as a three-dimensional substrate for colony formation capacity of mouse spermatogonial stem cells was determined. The morphological, degradation, biocompatibility, and swelling properties of the samples were fully characterized. The 0.5%/30 SDS/Triton showed optimal decellularization with minimal negative effects on ECM (P ≤ 0.05). The swelling ratios increased with the increase of SDS and Triton concentration and incubation time. Only 0.5%/15 and 30 SDS showed a significant decrease in the SSCs viability compared with other groups (P < 0.05). The SSCs colony formation was clearly observed under SEM and H&E stained slides. The cells infiltrated into the subcutaneously implanted scaffold at days 7 and 30 post-implantation with no sign of graft rejection. Our data suggest the %0.5/30 SDS/Triton as an excellent platform for tissue engineering and reproductive biology applications.

Advanced bioengineering of male germ stem cells to preserve fertility

In modern life, several factors such as genetics, exposure to toxins, and aging have resulted in significant levels of male infertility, estimated to be approximately 18% worldwide. In response, substantial progress has been made to improve in vitro fertilization treatments (e.g. microsurgical testicular sperm extraction (m-TESE), intra-cytoplasmic sperm injection (ICSI), and round spermatid injection (ROSI)). Mimicking the structure of testicular natural extracellular matrices (ECM) outside of the body is one clear route toward complete in vitro spermatogenesis and male fertility preservation. Here, a new wave of technological innovations is underway applying regenerative medicine strategies to cell-tissue culture on natural or synthetic scaffolds supplemented with bioactive factors. The emergence of advanced bioengineered systems suggests new hope for male fertility preservation through development of functional male germ cells. To date, few studies aimed at in vitro spermatogenesis have resulted in relevant numbers of mature gametes. However, a substantial body of knowledge on conditions that are required to maintain and mature male germ cells in vitro is now in place. This review focuses on advanced bioengineering methods such as microfluidic systems, bio-fabricated scaffolds, and 3D organ culture applied to the germline for fertility preservation through in vitro spermatogenesis.

Separating mouse malignant cell line (EL4) from neonate spermatogonial stem cells utilizing microfluidic device in vitro

BACKGROUND

Some children who have survived cancer will be azoospermic in the future. Performing isolation and purification procedures for spermatogonial stem cells (SSC) is very critical. In this regard, performing the process of decontamination of cancerous cells is the initial step. The major objective of the present study is to separate the malignant EL4 cell line in mice and spermatogonial stem cells in vitro.

METHODS

The spermatogonial stem cells of sixty neonatal mice were isolated, and the procedure of co-culturing was carried out by EL4 which were classified into 2 major groups: (1) the control group (co-culture in a growth medium) and (2) the group of co-cultured cells which were separated using the microfluidic device. The percentage of cells was assessed using flow cytometry technique and common laboratory technique of immunocytochemistry and finally was confirmed through the laboratory technique of reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

The actual percentage of EL4 and SSC after isolation was collected at two outlets: the outputs for the smaller outlet were 0.12% for SSC and 42.14% for EL4, while in the larger outlet, the outputs were 80.38% for SSC and 0.32% for EL4; in the control group, the percentages of cells were 21.44% for SSC and 23.28% for EL4 (based on t test (p ≤ 0.05)).

CONCLUSIONS

The present study demonstrates that the use of the microfluidic device is effective in separating cancer cells from spermatogonial stem cells.

Development of An Artificial Male Germ Cell Niche Using Electrospun Poly Vinyl Alcohol/Human Serum Albumin/Gelatin Fibers

Objective

Recent achievements in stem cell biotechnology, nanotechnology and tissue engineering have led to development of novel approaches in regenerative medicine. Azoospermia is one of the challenging disorders of the reproductive system. Several efforts were made for isolation and culture of testis-derived stem cells to treat male infertility. However, tissue engineering is the best approach to mimic the three dimensional microenvironment of the testis in vitro. We investigated whether human testis-derived cells (hTCs) obtained by testicular sperm extraction (TESE) can be cultured on a homemade scaffold composed of electrospun nanofibers of homogeneous poly (vinyl alcohol)/human serum albumin/gelatin (PVA/HSA/gelatin).

Materials and Methods

In this experimental lab study, human TCs underwent two steps of enzymatic cell isolation and five culture passages. Nanofibrous scaffolds were characterized by scanning electron microscopy (SEM) and Fourier- transform infrared spectroscopy (FTIR). Attachment of cells onto the scaffold was shown by hematoxylin and eosin (H&E) staining and SEM. Cell viability study using MTT [3-(4, 5-dimethyl-2-thiazolyl) -2, 5-diphenyl -2H- tetrazolium bromide] assay was performed on days 7 and 14.

Results

Visualization by H&E staining and SEM indicated that hTCs were seeded on the scaffold. MTT test showed that the PVA/HSA/gelatin scaffold is not toxic for hTCs.

Conclusion

It seems that this PVA/HSA/gelatin scaffold is supportive for growth of hTCs.

Colonization of Mouse Spermatogonial Cells in Modified Soft Agar Culture System Utilizing Nanofibrous Scaffold: A New Approach

Background:

Spermatogonial stem cells (SSCs) are considered in fertility management approaches of prepubertal boys facing cancer therapies. However, in vitro propagation has become an important issue due to a small number of SSCs in testicular tissue. The present study aimed to investigate a modified soft agar culture system by using a nanofibrous scaffold as a new approach to mimic in vivo conditions of SSCs development.

Materials and Methods:

The SSCs were isolated from neonate mouse testes, cultured on polycaprolactone scaffold, and covered by a layer of soft agar for 2 weeks. Then, the number and diameter of colonies formed in experimental groups were measured and spermatogonial markers (i.e., Plzf, Gfrα1, Id4, and c-Kit) in SSCs colonies were evaluated by a real-time polymerase chain reaction and immunostaining.

Results:

Our results indicated that the colonization rate of SSCs was significantly higher in the present modified soft agar culture system (P<0.05). Only Plzf indicated a significant increased at the levels (P<0.05), the gene expression levels of Id4, Plzf, and Gfrα1 were higher in the present culture system. In addition, the expression of the c-Kit gene as a differentiating spermatogonia marker was higher in presence of scaffold and soft agar compared with the amount of other experimental groups (P<0.05).

Conclusion:

The culture system by using nanofibrous scaffold and soft agar as a new culture method suggests the potential of this approach in SSCs enrichment and differentiation strategies for male infertility treatments, as well as in vitro spermatogenesis.

In Vitro Cytotoxicity of Folate-Silica-Gold Nanorods on Mouse Acute Lymphoblastic Leukemia and Spermatogonial Cells

OBJECTIVE

The purpose of this study was to evaluate in vitro cytotoxicity of gold nanorods (GNRs) on the viability of spermatogonial cells (SSCs) and mouse acute lymphoblastic leukemia cells (EL4s).

MATERIALS AND METHODS

In this experimental study, SSCs were isolated from the neonate mice, following enzymatic digestion and differential plating. GNRs were synthesized, then modified by silica and finally conjugated with folic acid to form F-Si-GNRs. Different doses of F-Si-GNRs (25, 50, 75, 100, 125 and 140 μM) were used on SSCs and EL4s. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) proliferation assay was performed to examine the GNRs toxicity. Flow cytometry was used to confirm the identity of the EL4s and SSCs. Also, the identity and functionality of SSCs were determined by the expression of specific spermatogonial genes and transplantation into recipient testes. Apoptosis was determined by flow cytometry using an annexin V/propidium iodide (PI) kit.

RESULTS

Flow cytometry showed that SSCs and EL4s were positive for Plzf and H-2kb, respectively. The viability percentage of SSCs and EL4s that were treated with 25, 50, 75, 100, 125 and 140 μM of F-Si-GNRs was 65.33 ± 3.51%, 60 ± 3.6%, 51.33 ± 3.51%, 49 ± 3%, 30.66 ± 2.08% and 16.33 ± 2.51% for SSCs and 57.66 ± 0.57%, 54.66 ± 1.5%, 39.66 ± 1.52%, 12.33 ± 2.51%, 10 ± 1% and 5.66 ± 1.15% for EL4s respectively. The results of the MTT assay indicated that 100 μM is the optimal dose to reach the highest and lowest level of cell death in EL4s and in SSCs, respectively.

CONCLUSION

Cell death increased with increasing concentrations of F-Si-GNRs. Following utilization of F-Si-GNRs, there was a significant difference in the extent of apoptosis between cancer cells and SSCs.

Characterization, recellularization, and transplantation of rat decellularized testis scaffold with bone marrow-derived mesenchymal stem cells

BACKGROUND

Regenerative medicine potentially offers the opportunity for curing male infertility. Native extracellular matrix (ECM) creates a reconstruction platform to replace the organs. In this study, we aimed to evaluate the efficiency of the testis decellularized scaffold as a proper niche for stem cell differentiation toward testis-specific cell lineages.

METHODS

Rats' testes were decellularized by freeze-thaw cycle followed by immersion in deionized distilled water for 2 h, perfused with 1% Triton X-100 through ductus deferens for 4 h, 1% SDS for 48 h and 1% DNase for 2 h. The decellularized samples were prepared for further in vitro and in vivo analyses.

RESULT

Histochemical and immunohistochemistry studies revealed that ECM components such as Glycosaminoglycans (GAGs), neutral carbohydrate, elastic fibers, collagen I & IV, laminin, and fibronectin were well preserved, and the cells were completely removed after decellularization. Scanning electron microscopy (SEM) showed that 3D ultrastructure of the testis remained intact. In vivo and in vitro studies point out that decellularized scaffold was non-toxic and performed a good platform for cell division. In vivo implant of the scaffolds with or without mesenchymal stem cells (MSCs) showed that appropriate positions for transplantation were the mesentery and liver and the scaffolds could induce donor-loaded MSCs or host migrating cells to differentiate to the cells with phenotype of the sertoli- and leydig-like cells. The scaffolds also provide a good niche for migrating DAZL-positive cells; however, they could not differentiate into post meiotic-cell lineages.

CONCLUSION

The decellularized testis can be considered as a promising vehicle to support cell transplantation and may provide an appropriate niche for testicular cell differentiation.

Organ culture of seminiferous tubules using a modified soft agar culture system

BACKGROUND

In-vitro spermatogenesis in mammalian species is considered an important topic in reproductive biology. New strategies for achieving a complete version of spermatogenesis ex vivo have been conducted using an organ culture method or culture of testicular cells in a three-dimensional soft agar culture system (SACS). The aim of this study was to develop a new method that supports spermatogenesis to the meiotic phase and morphologically mature spermatozoa through the culture of testicular cells and seminiferous tubules (STs) in a modified SACS, respectively.

METHODS

First, enzymatically dissociated testicular cells and mechanically dissociated STs of neonatal mice were separately embedded in agarose and then placed on the flat surface of agarose gel half-soaked in the medium to continue culture with a gas-liquid interphase method.

RESULTS

Following 40 days of culture, the meiotic (Scp3) and post-meiotic (Acr) gene expression in aggregates and STs was confirmed by real-time polymerase chain reaction. These results were complemented by immunohistochemistry. The presence of morphologically mature spermatozoa in the frozen sections of STs was demonstrated with hematoxylin and eosin staining. We observed Plzf- or Integrin α6-positive spermatogonia in both cultures after 40 days, indicating the potency of the culture system for both self-renewal and differentiation.

CONCLUSIONS

This technique can be used as a valuable approach for performing research on spermatogenesis and translating it into the human clinical setting.

The effects of melatonin on colonization of neonate spermatogonial mouse stem cells in a three-dimensional soft agar culture system

BACKGROUND

Melatonin is a pleiotropic hormone with powerful antioxidant activity both in vivo and in vitro. The present study aimed to investigate the effects of melatonin on the proliferation efficiency of neonatal mouse spermatogonial stem cells (SSCs) using a three-dimensional soft agar culture system (SACS) which has the capacity to induce development of SSCs similar to in vivo conditions.

METHODS

SSCs were isolated from testes of neonate mice and their purities were assessed by flow cytometry using PLZF antibody. Isolated testicular cells were cultured in the upper layer of the SACS in αMEM medium in the absence or presence of melatonin extract for 4 weeks.

RESULTS

The identity of colonies was confirmed by alkaline phosphatase staining and immunocytochemistry using PLZF and α6 integrin antibodies. The number and diameter of colonies of SSCs in the upper layer were evaluated at days 14 and 28 of culture. The number and diameter of colonies of SSCs were significantly higher in the melatonin group compared with the control group. The levels of expression of ID-4 and Plzf, unlike c-kit, were significantly higher in the melatonin group than in the control group.

CONCLUSIONS

Results of the present study show that supplementation of the culture medium (SACS) with 100 μM melatonin significantly decreased reactive oxygen species (ROS) production in the treated group compared with the control group, and increased SSC proliferation.

Generation of Mouse Spermatogonial Stem-Cell-Colonies in A Non-Adherent Culture

OBJECTIVE

The properties of self-renewal and division in spermatogonial stem cells (SSCs) support spermatogenesis. There is a number of reported methods for in vitro SSC culture systems. The development of a culture system that effectively supports isolation and selfrenewal of germline stem cells (GSCs) is of tremendous benefit for clinical trials, experimental research, and as potential treatment for male infertility. The current study aims to consider the cultivation and behavior of GSCs in a non-adherent culture system.

MATERIALS AND METHODS

In this experimental study, we cultured testicular cells from neonatal mice in agarose coated plates in the presence of Dulbecco's modified Eagle's medium (DMEM) medium (CTRL group), 10% fetal bovine serum (FBS)+DMEM (10% group), and growth factor (G group) that contained 2% FBS, glial cell-derived neurotrophic factor (GDNF), epidermal growth factor (EGF), and fibroblast growth factor (FGF). Mouse spermatogonial stem-like colonies were isolated approximately 3 weeks after digestion of the testis tissue. After passages 2-3, the identity of the mouse spermatogonial stem-like cells was confirmed by immunocytochemistry, reverse transcription-polymerase chain reaction (RT-PCR), and flow cytometry against the germ cell markers α6, β1, c-Kit, Thy-1, c-Ret, Plzf, and Oct4. The statistical significance between mean values in different groups was determined by one-way analysis of variance (ANOVA).

RESULTS

We observed spermatogonial stem-like colonies in the G and 10% groups, but not the CTRL group. Immunocytochemistry, flow cytometry, and RT-PCR confirmed expressions of germ cell markers in these cells. In the spermatogonial stem-like cells, we observed a significant expression (P<0.05) of germ cell markers in the G and 10% groups versus the testis cells (T). Their proliferative and apoptotic activities were examined by Ki67 and PI/annexin V-FITC. Alkaline phosphatase assay showed that mouse spermato- gonial stem-like colonies were partially positive.

CONCLUSION

A non-adherent culture system could provide a favorable method for in vitro short-term culture of spermatogonial stem-like cell colonies.

Characterization of A Three-Dimensional Organotypic Co-Culture Skin Model for Epidermal Differentiation of Rat Adipose-Derived Stem Cells

Objective

The organotypic co-culture is a well-known technique to examine cellular interactions and their roles in stem cell proliferation and differentiation. This study aims to evaluate the effects of dermal fibroblasts (DFs) on epidermal differentiation of adipose-derived stem cells (ASCs) using a three-dimensional (3D) organotypic co- culture technique.

Materials and Methods

In this experimental research study, rat DFs and ASCs were isolated and cultured separately on electrospun polycaprolactone (PCL) matrices. The PCL matrices seeded by ASCs were superimposed on to the matrices seeded by DFs in order to create a 3D organotypic co-culture. In the control groups, PCL matrices seeded by ASCs were placed on matrices devoid of DFs. After 10 days, we assessed the expressions of keratinocyte-related genes by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and expression of pan-cytokeratin protein by immunofluorescence in the differentiated keratinocyte-like cells from co- culture and control groups. Keratinocyte-like cell morphologies were also observed by scanning electron microscopy (SEM).

Results

The early, intermediate, and terminal differentiation keratinocyte markers-Cytokeratin14, Filaggrin, and Involucrin significantly expressed in the co-culture groups com- pared to the control ones (P<0.05). We observed pan-cytokeratin in keratinocyte-like cells of both groups by immunofluorescence. SEM observation of the co-culture groups showed that the differentiated keratinocyte-like cells developed a polygonal cobblestone shape, considered characteristic of keratinocytes.

Conclusion

The 3D organotypic co-culture bilayered construct that consisted of DFs and ASCs was an effective technique for epidermal differentiation of ASCs. This co-culture might be useful for epidermal differentiation of stem cells for future applications in skin regeneration.

Alteration of spermatogenesis following spermatogonial stem cells transplantation in testicular torsion-detorsion mice

PURPOSE

Testicular ischemia is the main consequence of testicular torsion, in both clinical and experimental aspects. Preservation and auto-transplantation of spermatogonial stem cells (SSCs) could be a new treatment for infertility in testicular ischemia following testicular torsion.

METHODS

To apply the idea in this study, animals were randomly divided into four groups of control, sham, with torsion, and with torsion followed by transplantation (TT). Isolated SSCs from neonatal mice were cultured and identified by flow cytometry (C-KIT(-), INTEGRIN β1 (+)) and RT-PCR (Reverse transcription polymerase chain reaction) for specific spermatogonial cell markers (Oct4, Gfrα-1, Plzf, Vasa, Itgα 6 , and Itgβ 1 ). SSCs were transplanted upon a 2-h testicular torsion in the TT group. Cultured cells were transplanted into ischemia reperfusion testicle 2 weeks post-testicular torsion. Eight weeks after SSCs transplantation, the SSCs-transplanted testes and epididymis were removed for sperm analysis, weight and histopathological evaluation, and pre- and post-meiotic gene expression assessment by qRT-PCR.

RESULTS

Our findings indicated that all evaluated parameters (epididymal sperm profile, Johnsen score, Plzf, Gfrα-1, Scp-1, Tekt-1 expressions, and histopathological profile) were significantly decreased following testicular torsion (group 3) when compared to the control group (p ≤ 0.05). However, all abovementioned parameters showed a significant increase/improvement in torsion-transplantation group compared to torsion group. However, these parameters in the TT group were significantly lower in the sham and control groups (p ≤ 0.05).

CONCLUSION

SSCs transplantation could up-regulate the expression of pre- and post-meiotic genes in testicular ischemia, which resulted in improvement of both testicular function and structure after testicular torsion.

The viability of mouse spermatogonial germ cells on a novel scaffold, containing human serum albumin and calcium phosphate nanoparticles

BACKGROUND

In spermatogenesis, spermatogonial cells differentiate to the haploid gametes. It has been shown that spermatogenesis can be done at in vitro condition. In vitro spermatogenesis may provide an open window to treat male infertility.

OBJECTIVE

The aim of this study was to evaluate the effects of a novel scaffold containing human serum albumin (HSA)/tri calcium phosphate nanoparticles (TCP NPs) on the mouse spermatogonial cell line (SCL).

MATERIALS AND METHODS

First, TCP NPs were synthesized by reaction of calcium nitrate and diammonium phosphate at pH 13. Then, serial concentrations of TCP NPs were separately added to 500 mg/mL HSA, and incubated in the 100(o)C water for 30 min. In the next step, each scaffold was cut (2×2mm), placed into sterile well of microplate, and then incubated for 1, 2, and 3 days at 37(o)C with mouse SCL. After incubation, the cytotoxicity of the scaffolds was evaluated by different tests including 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) assay, vital staining, and cell counting. On the other hand, the release of TCP NPs and HSA from the scaffolds was measured.

RESULTS

Based on microscopic observation, the size of cavities for all scaffolds was near 200-500 µm, and the size of TCP NPs was near 50-100 nm. All toxicity tests showed that the increase of TCP concentration in the scaffold did not affect mouse SCL. It means that the percentage of cell viability, LDH release, vital cells, and cell quantity was 85%, 105%, 90%, and 110%, respectively. But, the increase of incubation time led to increase of LDH release (up to 115%) and cell count (up to 115%). Also, little decrease of cell viability and vital cells was seen when incubation time was increased. Here, no release of TCP NPs and HSA was seen after increase of TCP concentration and incubation time.

CONCLUSION

It can be concluded that the increase of TCP concentration in HSA/ TCP NPs scaffold does not lead to cytotoxicity. On the other hand, the increase of incubation time leads to increase of mouse SCL cell death. In this study, it was found that TCP NPs and HSA could not release from the scaffolds. In future, both proliferation and differentiation of mouse SCL on HSA/TCP NPs scaffold must be checked over more wide incubation times.