Wistar rats immature testicular tissue vitrification and heterotopic grafting

Advancements in fertility preservation strategies for pediatric male cancer patients: a review of cryopreservation and transplantation of immature testicular tissue

Recently, there has been increasing emphasis on the gonadotoxic effects of cancer therapy in prepubertal boys. As advances in oncology treatments continue to enhance survival rates for prepubertal boys, the need for preserving their functional testicular tissue for future reproduction becomes increasingly vital. Therefore, we explore cutting-edge strategies in fertility preservation, focusing on the cryopreservation and transplantation of immature testicular tissue as a promising avenue. The evolution of cryopreservation techniques, from controlled slow freezing to more recent advancements in vitrification, with an assessment of their strengths and limitations was exhibited. Detailed analysis of cryoprotectants, exposure times, and protocols underscores their impact on immature testicular tissue viability. In transplantation strategy, studies have revealed that the scrotal site may be the preferred location for immature testicular tissue grafting in both autotransplantation and xenotransplantation scenarios. Moreover, the use of biomaterial scaffolds during graft transplantation has shown promise in enhancing graft survival and stimulating spermatogenesis in immature testicular tissue over time. This comprehensive review provides a holistic approach to optimize the preservation strategy of human immature testicular tissue in the future.

Optimizing Immature Testicular Tissue and Cell Transplantation Results: Comparing Transplantation Sites and Scaffolds

For patients who had testicular tissue cryopreserved before receiving gonadotoxic therapies, transplantation of testicular tissues and cells has been recommended as a potential therapeutic option. There are no studies that indicate the generation of sperm after human immature testicular tissue (ITT) or spermatogonial stem cells (SSCs) transplantation. The use of releasing scaffolds and localized drug delivery systems as well as the optimizing transplantation site can play an effective role in increasing the efficiency and improving the quality of testicular tissue and cell transplantation in animal models. Current research is focused on optimizing ITT and cell transplantation, the use of releasing scaffolds, and the selection of the right transplantation site that might restore sperm production or male infertility treatment. By searching the PubMed and Google Scholar databases, original and review papers were collected. Search terms were relevant for SSCs and tissue transplantation. In this review, we'll focus on the potential advantages of using scaffolds and choosing the right transplantation site to improve transplantation outcomes.

Evaluation of Apoptosis-related Genes and Hormone Secretion Profiles Using Three Dimensional Culture System of Human Testicular Organoids

BACKGROUND

In reproductive biology, testicular organoids can be used to treat infertility and to study testicular development and spermatogonial stem cells (SSCs) differentiation. Generating organoid from primary cells is challenging. In this study, testicular organoids were created using human primary testicular cells and evaluated the apoptotic gene expression and hormone secretion profiles of the organoids.

MATERIALS AND METHODS

Primary human testicular cells were isolated using 2-step enzymatic digestion from three brain-dead donors. Immunocytochemistry and flow cytometry analyses were performed to confirm human SSCs. Isolated cells were cultured in three experimental groups: control group (2 dimensional (2D)), group 1 (organoid culture after 2D culture), and group 2 (organoid culture immediately after enzymatic digestion). Testicular organoids were cultured in DMEM/F-12 media supplemented with follicle-stimulating hormone (FSH) and fetal bovine serum (FBS) for four weeks. After 24 hours and four weeks of culture, reverse transcription quantitative real-time PCR (RT-qPCR) was used to investigate the relative expression of apoptotic genes (caspase 3, 9, Bax, and Bcl-2). At 24 hours, two weeks, and four weeks after culture, enzyme-linked immunoassay (ELISA) was used to determine the testosterone and inhibin B concentrations. Light microscopy and toluidine blue staining were also used for morphological analysis.

RESULTS

RT-qPCR results revealed that pro-apoptotic (caspase 3, 9, Bax) gene expression levels were highest in group 2 after 24 h and four weeks of culture. In contrast, the expression level of Bcl-2 (anti-apoptotic) was lower in group 2 compared to other groups. The hormone secretion levels decreased in a time-dependent manner during the cultivation. According to morphological evaluations, testicular organoids are compact, spherical structures with two to three elongated cells organized along their border.

CONCLUSION

Our findings revealed that the testicular organoid culture system maintained hormonal secretory abilities, demonstrating the function of Sertoli and Leydig cells in the absence of testis-specific environments.

Comparison of the effects of three cryoprotectants on the cryopreservation of mouse subcutaneous tissue under different conditions

The subcutaneous tissue of animals contains different cell types, and different cells have different requirements for cryopreservation. This establishes obstacles that need to be overcome in the clinical application of tissue preservation. In the present study, the effects of different freezing rates and various concentrations of cryoprotectants on the cryopreservation of subcutaneous tissue of mice were compared, and these results provided basic research data that can be used to explore the optimal cryopreservation method for tissue. The effects of three cryoprotectants, dimethyl sulfoxide, glycerinum and 1,2-propanediol, and their concentrations on the cryopreservation of subcutaneous tissue of mice were compared with slow and rapid freezing rates. The results revealed that under various cryopreservation conditions, the percentage of fibroblasts that grow from the tissue following slow cryopreservation (19.8%) was significantly higher than that following rapid freezing (6.7%) at osmotic equilibrium for 10-20 min (P<0.05). After 19 days of culture, under the conditions of slow freezing, with 10, 20 and 30% glycerinum as a cryoprotectant, respectively, fibroblasts grew from 26.0, 16.7 and 16.7% of the tissues, respectively. No fibroblasts were indicated in the tissue mass cultured in any other tissue blocks treated with cryopreservation solutions. Under the condition of rapid freezing, fibroblasts grew from 6.7 and 6.7% tissue blocks of 20% DMSO and 10% glycerinum, respectively, following 19 days of culture. No fibroblasts were identified in the tissue mass cultured in the other tissue blocks treated with cryopreservation solutions, and no fibroblasts were identified in the tissue blocks without osmotic balance before freezing.

Gene expression analysis of ovine prepubertal testicular tissue vitrified with a novel cryodevice (E.Vit)

PURPOSE

Testicular tissue cryopreservation prior to gonadotoxic therapies is a method to preserve fertility in children. However, the technique still requires development, especially when the tissue is immature and rather susceptible to stress derived from in vitro manipulation. This study aimed to investigate the effects of vitrification with a new cryodevice (E.Vit) on cell membrane integrity and gene expression of prepubertal testicular tissue in the ovine model.

METHODS

Pieces of immature testicular tissue (1 mm³) were inserted into "E.Vit" devices and vitrified with a two-step protocol. After warming, tissues were cultured in vitro and cell membrane integrity was assessed after 0, 2, and 24 h by trypan blue exclusion test. Controls consisted of non-vitrified tissue analyzed after 0, 2, and 24 h in vitro culture (IVC). Expression of genes involved in transcriptional stress response (BAX, SOD1, CIRBP, HSP90AB1), cell proliferation (KIF11), and germ- (ZBDB16, TERT, POU5F1, KIT) and somatic- (AR, FSHR, STAR) cell specific markers was evaluated 2 and 24 h after warming.

RESULTS

Post-warming trypan blue staining showed the survival of most cells, although membrane integrity immediately after warming (66.00% ± 4.73) or after 2 h IVC (59.67% ± 4.18) was significantly lower than controls (C0h 89.67% ± 1.45). Extended post-warming IVC (24 h) caused an additional decrease to 31% ± 3.46 (P < 0.05). Germ- and somatic-cell specific markers showed the survival of both cell types after cryopreservation and IVC. All genes were affected by cryopreservation and/or IVC, and moderate stress conditions were indicated by transcriptional stress response.

CONCLUSIONS

Vitrification with the cryodevice E.Vit is a promising strategy to cryopreserve prepubertal testicular tissue.