Astaxanthin Relieves Busulfan-Induced Oxidative Apoptosis in Cultured Human Spermatogonial Stem Cells by Activating the Nrf-2/HO-1 pathway.

Many child cancer patients endure anticancer therapy containing alkylating agents before sexual maturity. Busulfan (BU), as an alkylating agent, is a chemotherapy drug, causing DNA damage and cytotoxicity in germ cells. In the present study, we aimed to investigate the protective effect of astaxanthin (AST), as a potent antioxidant and powerful reactive oxygen species (ROS) scavenger, on BU-induced toxicity in human spermatogonial stem cells. For this purpose, testes were obtained from four brain-dead donors. After tissue enzymatic digestions, testicular cells were cultured for 3 weeks for spermatogonial stem cell (SSC) isolation and purification. K562 cell line was cultured to survey the effect of AST on cancer treatment. The cultured SSCs and K562 cell line were finally treated with AST (10µM), BU (0.1nM), and AST+BU. The expression of NRF-2, HO-1, SOD2, SOD3, TP53, and apoptotic genes, including CASP9, CASP3, BCL2, and BAX, were assayed using real-time PCR. Moreover, ROS level in different groups and malondialdehyde level and total antioxidant capacity in cell contraction of SSCs were measured using ELISA. Data showed that AST significantly upregulated the expression of NRF-2 gene (P<0.001) and protein (P<0.005) and also significantly decreased the production of BU-induced ROS (P<0.001). AST activated the NRF-2/HO-1 pathway that could remarkably restrain BU-induced apoptosis in SSCs. Interestingly, AST upregulated the expression level of apoptosis genes in the K562 cell line. The results of this study indicated that AST reduces the side effects of BU on SSCs without interference with its chemotherapy effect on cancerous cells through modulation of the NRF-2/HO-1 and mitochondria-mediated apoptosis pathways.

Genetic and epigenetic stability of human spermatogonial stem cells during long-term culture.

OBJECTIVE: To determine the genetic and epigenetic stability of human spermatogonial stem cells (SSCs) during long-term culture. DESIGN: Experimental basic science study. SETTING: Reproductive biology laboratory. PATIENT(S): Cryopreserved human testicular tissue from two prostate cancer patients with normal spermatogenesis. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Testicular cells before and 50 days after culturing were subjected to ITGA6 magnetic-activated cell sorting to enrich for SSCs. Individual spermatogonia were analyzed for aneuploidies with the use of single-cell 24-chromosome screening. Furthermore, the DNA methylation statuses of the paternally imprinted genes H19, H19-DMR (differentially methylated region), and MEG3 and the maternally imprinted genes KCNQ1OT1 and PEG3 were identified by means of bisulfite sequencing. RESULTS(S): Aneuploidy screening showed euploidy with no chromosomal abnormalities in all cultured and most noncultured spermatogonia from both patients. The methylation assays demonstrated demethylation of the paternally imprinted genes H19, H19-DMR, and MEG3 of 11%-28%, 43%-68%, and 18%-26%, respectively, and increased methylation of the maternally imprinted genes PEG 3 and KCNQ1OT of 13%-50% and 30%-38%, respectively, during culture. CONCLUSION(S): In the current culture system for human SSCs propagation, genomic stability is preserved, which is important for future clinical use. Whether the observed changes in methylation status have consequences on functionality of SSCs or health of offspring derived from transplanted SSCs requires further investigation.

Isolation and culture of human spermatogonial stem cells derived from testis biopsy.

BACKGROUND: In cancer patients, chemo and radiotherapy can cause infertility by damaging spermatogenesis process. This process is based on self-renewal and differentiation of a rare population of the testicular cells called Spermatogonial Stem Cells (SSCs). Scientists have tried to isolate, enrich and culture Human spermatogonial stem cells, hoping to resolve infertility problems in cancer recovered patients in the future. METHODS: Spermatogonial stem cells were isolated and purified from human testicular biopsies sample consisting of at least 500,000 and at most 2,000,000 cells. Two enzymatic digestion steps were performed. Enriching methods, differential plating, and specific culture in serum-free medium with added growth factors: human GDNF, bFGF, EGF and LIF was performed on coated dishes. RESULTS: Human spermatogonial stem cell clusters were observed after 7 to 10 days in specific culture, then after several passages and successful expanding duration of 52 days, the cells were evaluated by three layer immunocytochemistry test (LSAB) to stain GPR125 protein as a surface marker in human spermatogonial stem cells. CONCLUSION: In current study human spermatogonial stem cell were isolated and expanded with the least manipulations in comparison with the other usual isolation methods like florescent or magnetic activated cell sorting. In contrast to the other SSCs isolation and culture methods, this system is based on the testicular biopsies against large samples, thus suggested method in this study is closer to clinical usage in the future.