Morphological and ultrastructural studies of human spermatogonial stem cells from patients with maturation arrest.

Destruction of spermatogonial stem cells (SSCs) along the chemotherapy and radiotherapy is one of the side effects of cancer treatments that lead to infertility. In vitro propagation of hSSCs is necessary to obtain an adequate number of cells for successful transplantation. In this study, hSSCs were isolated from testis biopsies of the patients with maturation arrest and proliferated in DMEM in the presence of LIF and bFGF for 5 weeks. The various types of human spermatogonia were identified in culture system and compared with testis tissue using morphological criteria at the ultrastructural level. The results showed that although many various types of spermatogonia were identified, but no remarkable difference was observed between spermatogonial cells in culture system and testis tissue. Electron and light microscopic studies of hSSC colonies did not show differentiated SSCs in the culture system. The results also showed that probably the suitable time for transplanting of SSCs in recipient testis is 2-3 weeks after culture. Because apoptosis which may affect the development of germ cells has not started in colony cells at this time and the population of apoptotic cells are low.

Evaluation of the effects of cryopreservation on viability, proliferation and colony formation of human spermatogonial stem cells in vitro culture.

Proliferation of spermatogonial stem cells (SSCs) in vitro system is very important. It can enhance SSCs numbers for success of transplantation and treatment of infertility in cancer patients. In this study, testicular cells that obtained from azoospermia patients (n=8) by enzymatic digestion were cryopreserved at the beginning and after 2 weeks of culture. Then, frozen-thawed SSCs were co-cultured on fresh Sertoli cells (experimental group 1), and frozen-thawed Sertoli cells (experimental group 2) for another 3 weeks. In control group, fresh SSCs were co-cultured on fresh Sertoli cells. Viability rate after enzymatic digestion was 93.4%±5.0. Frozen-thawed testicular cells after 2 weeks of culture had a significantly (P<0.05) higher percentage of living cells compared to frozen-thawed testicular cells at the beginning of culture (59.2±7.05 and 46.3±8.40 respectively). The number of colonies in the experimental group 1 was significantly higher than experimental group 2 (19.6±2.8 and 8.33±1.5, respectively, P<0.05). The diameter of the colonies in the experimental group 1 was significantly higher than control and experimental group 2 (P<0.05) after 3 weeks of culture (269.7±52.1, 204.34±24.1 and 112.52±23.5 µm, respectively). Cryopreservation technique will raise the possibility of banking SSCs for men who have a cancer-related illness and waiting for radiotherapy and/or chemotherapy.

Effects of basic fibroblast growth factor and leukaemia inhibitory factor on proliferation and short-term culture of human spermatogonial stem cells.

In this study, isolated spermatogonial stem cells (SSCs) and Sertoli cells using enzymatic digestion from patients with maturation arrest of spermatogenesis were grown in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% foetal calf serum in three different groups: (1) SSCs cultured without Sertoli cells (2) SSCs co-cultured with Sertoli cells (as control group), (3) SSCs co-cultured with Sertoli cells and adding different concentrations of basic fibroblast growth factor (0.1, 1, 10 ng ml(-1)) and human leukaemia inhibitory factor (1000, 1200, 1500 unit ml(-1)) as experimental groups. The assessment of colonies every 10 days during 5-week cultures showed that in the first group, the average number and diameter of the colonies were significantly lower than in the other groups (P < 0.05). The largest number of colonies was observed in control condition (32.29 ± 9.15) in day 30. The largest diameter of colonies was formed in combination dosages of 1 ng ml(-1) basic fibroblast growth factor (bFGF) + 1500 unit ml(-1) leukaemia inhibitory factor (LIF) (302.93 ± 37.68) and 10 ng ml(-1) bFGF and 1200 unit ml(-1) LIF (262.87 ± 35.54) in day 30 respectively. Isolated SSCs were positive for spermatogonial cell markers such as Oct4, Stra8, Piwil2 and Vasa but negative for Nanog. Transplantation technique indicated that hSSCs have good efficiency for colonisation of mouse seminiferous tubules after proliferation in culture system.