Effect of Temperature on the Development of Stages of Spermatogenesis and the Functionality of Sertoli Cells In Vitro

Spermatogenesis is the process of proliferation and differentiation of spermatogonial cells to meiotic and post-meiotic stages and sperm generation. Normal spermatogenesis occurs in vivo at 34 °C to 35 °C, and high temperatures are known to cause male infertility. The aim of the present study was to examine the effect of temperature (35 °C compared to 37 °C) on the viability/apoptosis of developed cells, on the development of different stages of spermatogenesis in 3D in vitro culture conditions, and the functionality of Sertoli cells under these conditions. We used isolated cells from seminiferous tubules of sexually immature mice. The cells were cultured in methylcellulose (as a three-dimensional (3D) in vitro culture system) and incubated in a CO2 incubator at 35 °C or 37 °C. After two to six weeks, the developed cells and organoids were collected and examined for cell viability and apoptosis markers. The development of different stages of spermatogenesis was evaluated by immunofluorescence staining or qPCR analysis using specific antibodies or primers, respectively, for cells at each stage. Factors that indicate the functionality of Sertoli cells were assessed by qPCR analysis. The developed organoids were examined by a confocal microscope. Our results show that the percentages and/or the expression levels of the developed pre-meiotic, meiotic, and post-meiotic cells were significantly higher at 35 °C compared to those at 37 °C, including the expression levels of the androgen receptor, the FSH receptor, transferrin, the androgen-binding protein (ABP), and the glial-derived nerve growth factor (GDNF) which were similarly significantly higher at 35 °C than at 37 °C. The percentages of apoptotic cells (according to acridine orange staining) and the expression levels of BAX, FAS, and CASPAS 3 were significantly higher in cultures incubated at 37 °C compared to those incubated at 35 °C. These findings support the in vivo results regarding the negative effect of high temperatures on the process of spermatogenesis and suggest a possible effect of high temperatures on the viability/apoptosis of spermatogenic cells. In addition, increasing the temperature in vitro also impaired the functionality of Sertoli cells. These findings may deepen our understanding of the mechanisms behind optimal conditions for normal spermatogenesis in vivo and in vitro.

Granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced maturation of spermatogonial cells from prepubertal mice in vitro is enhanced by testosterone

Spermatogenesis is the complicated process of sperm generation. During this process, spermatogonial cells proliferate and differentiate via meiotic and post-meiotic stages to produce mature sperm. This process is under the regulation of testicular autocrine/paracrine factors. In addition, endocrine factors are crucial to complete spermatogenesis. We aimed to localize granulocyte-macrophage colony-stimulating factor (GM-CSF) and its receptor (GM-CSFR) in testicular cells and further evaluate its involvement in the development of spermatogenesis in vitro. We isolated cells from seminiferous tubule cells of seven-day-old mice and cultured them in vitro using a methylcellulose culture system (MCS), in the presence of GM-CSF and/or testosterone for four weeks. The cells were then examined for markers of different stages of spermatogenesis by immunofluorescence staining and/or qPCR analyses. Our results revealed the presence of GM-CSF and GM-CSFR in testicular cells (premeiotic and meiotic cells as well as somatic cells; Leydig and Sertoli cells). We further demonstrated the development of colonies/spheroids in the MCS which contained pre-meiotic, meiotic, and post-meiotic cells. The addition of GM-CSF to the MCS significantly increased the percentage of pre-meiotic and meiotic cells compared to control. Furthermore, the addition of GM-CSF and testosterone together significantly increased the percentage of cells in the post-meiotic stage compared to the addition of each separately. In conclusion, our results indicate that testicular cells express GM-CSF/GM-CSFR, and that GM-CSF is involved in the development of different stages of spermatogenesis in vitro. Furthermore, testosterone enhances the development of spermatogenic cells and potentiates the effect of GMCSF on the development of post-meiotic cells. These findings provide evidence that GM-CSF and testosterone are involved in the development of spermatogenesis in vitro and in vivo. In brief: Testicular somatic and germ cells express GM-CSF and GM-CSFR. Our study suggests that testicular GM-CSF is involved in the development of spermatogenesis, which is potentiated by testosterone.

O-264 Testosterone potentiates the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the maturation of spermatogonial cells in vitro from prepubertal mice

Study question

Can granulocyte-macrophage colony-stimulating factor (GM-CSF) and testosterone induce spermatogonial cells to develop spermatogenesis in vitro using methylcellulose culture system (MCS)?

Summary answer

GM-CSF and testosterone induced the development of premeiotic and meiotic cells in vitro. Testosterone also induced and potentiate the development of post-meiotic cells by GM-CSF.

What is known already

Spermatogenesis is a complicated process of sperm generation. During this process spermatogonial cells proliferate and differentiate to meiotic, postmeiotic stages that continue in spermiogenesis to generate mature sperm. This process is under regulation of autocrine and paracrine factors provided by developed germ cells and somatic cells such as Sertoli, peritubular and Leydig cells. In addition, endocrine factors such as FSH, LH and testosterone are crucial for complete spermatogenesis. Different in vitro culture systems were used to induce the development of complete spermatogenesis in vitro, however this was not yet achieved.

Study design, size, duration

Sexually immature mice (7-day-old) were used to isolated cells from the seminiferous tubules. These isolated ells were cultured in methylcellulose culture system (MCS) as a 3-dimensinal in vitro system. Granulocyte-macrophage colony-stimulating factor (GM-CSF) and testosterone were added in the beginning of the cultures and after two weeks. The cultures were determined after 4 weeks.

Participants/materials, setting, methods

Cells were enzymatically isolated from the seminiferous tubules and cultured (2x105/well/0.5ml) in MCS that contained StemPro-34 medium, KSR, rEGF, rGDNF, rLIF, and r-bFGF. The cultures were grown in the presence/absence of GM-CSF (0.1 or 1ng/ml) and/or testosterone (10-7M) and incubated for four weeks in a CO2 incubator at 37°C. The developed cells and colonies/spheroids were examined microscopically, and quantified the developing cells of the different stages of spermatogenesis by immunofluorescence staining (IF) and/or qPCR analyses

Main results and the role of chance

Our results show the presence of GM-CSF and its receptor (GM-CSFR) in different testicular cells. We demonstrate the development of colonies/spheroids which contain premeiotic, meiotic and post-meiotic cells in MCS, as examined by IF and qPCR analyses. The percentage of pre-meiotic and miotic stage in the cultures with GM-CSF were significantly higher than those in the control group (p < 0.001), and the percentage of cells of the post-meiotic stage were significantly higher in the cultures with GM-CSF and testosterone together compared to each one separately (p < 0.001). In conclusion, testicular cells express GM-CSF/GM-CSFR, and GM-CSF affects only the development of premeiotic and meiotic cells in vitro. In addition, testosterone not only increased the development of cells from the premeiotic, meiotic and post-meiotic stages, but it also potentiated the effect of GM-CSF on the development of post-meiotic cells in vitro.

Limitations, reasons for caution

no limitation

Wider implications of the findings

These findings providing evidence that GM-CSF and testosterone could be used to improve the maturation of spermatogonial cells in vitro and that they might play a role in the maturation process of spermatogonial cells in vivo.

Trial registration number

not applicable