Ran Lee

Establishment and in vitro culture of porcine spermatogonial germ cells in low temperature culture conditions

The objective of this study was to establish a porcine spermatogonial germ cell (pSGC) line and develop an in vitro culture system. Isolated total testicular cells (TTCs) from 5-day-old porcine testes were primary cultured at 31, 34, and 37°C. Although the time of colony appearance was delayed at 31°C, strong alkaline phosphatase staining, expressions of pluripotency marker genes such as OCT4, NANOG, and THY1, and the gene expressions of the undifferentiated germ cell markers PLZF and protein gene product 9.5 (PGP9.5) were identified compared to 34 and 37°C. Cell cycle analysis for both pSGC and feeder cells at the three temperatures revealed that more pSGCs were in the G2/M phase at 31°C than 37°C at the subculture stage. In vitro, pSGCs could stably maintain undifferentiated germ cell and stem cell characteristics for over 60days during culture at 31°C. Xenotransplantation of pSGCs to immune deficient mice demonstrated a successful colonization and localization on the seminiferous tubule basement membrane in the recipient testes. In conclusion, pSGCs from neonatal porcine were successfully established and cultured for long periods under a low temperature culture environment in vitro.

Identification and In Vitro Derivation of Spermatogonia in Beagle Testis

Background In vitro culture of spermatogonial stem cells (SSCs) is important for exploration of SSCs self-renewal, differentiation, and manipulation. There are several reports on rodent SSC cultures; however, data on SSC cultures in domestic animals are limited. To provide basic scientific information on canine SSC cultures, we report canine testes development, and the development of spermatogonia-derived colonies (SDCs) for in vitro cultures. Methodology/Principal Findings Testes from 2-, 3-, and 12-month-old beagles were used for histology, immunohistochemistry, in vitro culture, immunocytochemistry, and PCR. Protein gene product 9.5 (PGP9.5)-positive spermatogonia, both single and paired, were found to be abundant in the testes of 2-month-old beagles. stempro-34 and Dulbeccos modified Eagle medium with 5% fetal bovine serum provided as useful substrates for culture of SDCs, and fibroblast growth factor (FGF) played a key role in colony formation. Colonies were positive for alkaline phosphatase and anti-PGP9.5 staining. The early spermatogonia and stem cell markers such as octamer binding protein 4 (Oct4), Nanog homeobox (Nanog), promyelocytic leukemia zinc finger (PLZF), PGP9.5, and GDNF family receptor alpha-1 (GFRα-1) were expressed in the colonies at higher levels than in the testis tissue. Conclusions Testes of the 2-month-old beagles had abundant single and paired spermatogonia, which can be used for derivation of SDCs, and FGF was important for colony formation.

Biochanin A Ameliorates Arsenic-Induced Hepato- and Hematotoxicity in Rats

Biochanin A (BCA) is a natural organic compound of the phytoestrogenic isoflavone class that has antioxidant and metal chelator properties in the presence of transition metal ions, however, its efficacy in animal models is still obscure. Therefore, the objective of this study was to investigate the protective effects of BCA against arsenic-induced hepatic injury and hematotoxicity in rats. The results suggest that arsenic intoxicated rats showed significantly higher levels of plasma hepatic markers than normal control rats. Furthermore, an increase in lipid peroxidation with depletion of reduced glutathione (GSH) and activities of superoxide dismutase (SOD) and catalase (CAT) occurred in the livers of rats exposed to arsenic. Administration of BCA (20 mg/kg·bw/day) and selenium (3 mg/kg·bw/day) resulted in a significant reversal of hepatic and oxidative stress markers in arsenic-intoxicated rats. A low dose of BCA (10 mg/kg·bw/day) did not show any preventive effect, while a high dose of BCA (40 mg/kg·bw/day) partially prevented all hepatotoxicity events. These biochemical perturbations were supported by histopathological observations of the liver. Our results suggest that administration of BCA (20 mg/kg·bw/day) attenuated the arsenic hepatotoxicity, a property that could contribute to the therapeutic approaches for chronic liver diseases.

Characterization of male germ cell markers in canine testis

Spermatogenesis begins at puberty and continues throughout a males life. This process is initiated and maintained by spermatogonial stem cells in the seminiferous tubules, and these cells produce haploid spermatozoa. Markers of male germ cells have been fully identified in rodents, including mice and rats, but not in canines. To characterize the canine male germ cells, histological and immunohistochemical analyses were performed, using prepubertal (1-3-month-old), early pubertal (4-month-old), and postpubertal (7-month-old) dog testes. Expression of protein gene product 9.5 (PGP9.5), deleted in azoospermia-like (DAZL), synaptonemal complex protein (SCP3), tyrosine-protein kinase Kit (C-kit), and acrosin was confirmed by immunohistochemical analysis. PGP9.5 and DAZL were detected in spermatogonia and co-localized near the basement membrane of seminiferous tubules. Some SCP3-positive cells expressed PGP9.5 but not C-kit, and most of these cells were located near the basement membrane. C-kit is a marker of differentiated spermatogenic cells. In addition, acrosin was detected in C-kit-positive spematocytes and mature spermatozoa, whereas C-kit was detected in Sertoli cells in all stages of canine testis development. We suggest that male germ cell markers detected in other species are conserved in canines. PGP9.5, DAZL, SCP3, and acrosin expressions were conserved among various species, but C-kit expression varied. This study might facilitate the identification of stage-specific canine germ cell markers and cellular mechanisms of spermatogenesis.

Stage-specific expression of Sal-like protein 4 in boar testicular germ cells

Spermatogenesis, the complex process of sperm cell development including mitotic cell division and meiosis, relies on spermatogonial stem cells (SSCs). While markers for developing germ cells have been well investigated in mice, developmental stage-specific markers of germ cells in domestic animals have not been identified. Sal-like protein 4 (SALL4) is known as a putative marker for undifferentiated spermatogonia in rodents; however, its expression in domestic animals has not been investigated. The objective of this study was to characterize the expression of SALL4 in the developmental stages of boar testes and SSCs. Interestingly, all SALL4-expressing cells responded positively to PGP9.5, which is known as a spermatogonia marker in boar testes, while some PGP9.5-positive cells did not express SALL4 in pre-pubertal boar testes. At this stage, the expression of SALL4 was observed in GFRα1-positive cells, and its expression was maintained in cultured pSSCs inxa0vitro, suggesting that SALL4 is a marker of early-stage boar spermatogonia that express GFRα1 in pre-pubertal testes. Additionally, SALL4 expression was observed in c-Kit-positive but not in PGP9.5- or SCP3-positive cells in post-pubertal testes. In conclusion, SALL4 is expressed in early undifferentiated spermatogonia in pre-pubertal boar testes and in primary spermatocytes in post-pubertal boar testes. Therefore, SALL4 can be used as a stage-specific marker of developing germ cells in boar testes.

Analysis of putative biomarkers of undifferentiated spermatogonia in dog testis

Spermatogenesis begins after puberty and continues throughout a males life, and is regulated by spermatogonial stem cells in the seminiferous tubules. Markers of male germ cells, including undifferentiated spermatogonia to fully developed spermatozoa have been identified in rodents, but not in dogs. In this study, to characterize the markers of undifferentiated spermatogonia, histological and immunohistochemical analyses were performed on pre-pubertal (1-month-old), early pubertal (4-month-old), and post-pubertal (7-month-old) dog testes. Expression of chemokine receptor 4 (CXCR4), insulin-like growth factor binding protein 3 (IGFBP3), LIN28, and Sal-like protein 4 (SALL4) genes was confirmed by immunohistochemical analysis. In pre-pubertal and early pubertal dog testes, CXCR4, IGFBP4, and LIN28 genes were expressed in undifferentiated spermatogonia, whereas the SALL4 gene was not expressed in the pre-pubertal stage. In adult dog testes, CXCR4 and IGFBP3 gene expression was detected in undifferentiated spermatogonia and co-localized with protein gene product 9.5 (PGP9.5) near the basement membrane of the seminiferous tubules. The LIN28 and SALL4 genes were expressed in synaptonemal complex protein 3-positive spermatocytes. The CXCR4 and IGFBP3 gene expression is conserved among other species, while LIN28 and SALL4 gene expression varies. Based on results of the present study, it is suggested that undifferentiated spermatogonia markers detected in other species are conserved in dogs. These results may facilitate further studies of the cellular mechanisms of spermatogenesis in dogs.

Establishment of a surgically induced cryptorchidism canine recipient model for spermatogonial stem cell transplantation.

Transplantation of spermatogonial stem cells (SSCs) in experimental animal models has been used to study germ line stem cell biology and to produce transgenic animals. The species-specific recipient model preparation is important for the characterization of SSCs and the production of offspring. Here, we investigated the effects of surgically induced cryptorchidism in dog as a new recipient model for spermatogonial stem cell transplantation. Artificially unilateral or bilateral cryptorchidism was induced in ten mature male dogs by surgically returning the testis and epididymis to the abdominal cavity. The testes and epididymides were collected every week after the induction of artificial cryptorchidism (surgery) for one month. To determine the effect of surgical cryptorchidism, the seminiferous tubule diameter was measured and immunohistochemistry using PGP9.5 and GATA4 antibodies was analyzed. The diameters of the seminiferous tubules of abdominal testes were significantly reduced compared to those of the scrotal testes. Immunohistochemistry results showed that PGP9.5 positive undifferentiated spermatogonia were significantly reduced after surgical cryptorchidism induction, but there were no significant changes in GATA-4 positive sertoli cells. To evaluate the testis function recovery rate, orchiopexy was performed on two dogs after 30 days of bilateral cryptorchidism. In the orchiopexy group, SCP3 positive spermatocytes were detected, and spermatogenesis was recovered 8 weeks after orchiopexy. In this study, we provided optimum experimental conditions and time for surgical preparation of a recipient canine model for SSC transplantation. Additionally, our data will contribute to recipient preparation by using surgically induced cryptorchidism in non-rodent species.

Mammary alveolar cell as in vitro evaluation system for casein gene expression involved in glucose level

Objective Glucose is an essential fuel in the energy metabolism and synthesis pathways of all mammalian cells. In lactating animals, glucose is the major precursor for lactose and is a substrate for the synthesis of milk proteins and fat in mammary secretory (alveolar) epithelial cells. However, clear utilization of glucose in mammary cells during lactogenesis is still unknown, due to the lack of in vitro analyzing models. Therefore, the objective of this study was to test the reliability of the mammary alveolar (MAC-T) cell as an in vitro study model for glucose metabolism and lactating system. Methods Undifferentiated MAC-T cells were cultured in three types of Dulbecco’s modified Eagle’s medium with varying levels of glucose (no-glucose: 0 g/L, low-glucose: 1 g/L, and high-glucose: 4.5 g/L) for 8 d, after which differentiation to casein secretion was induced. Cell proliferation and expression levels of apoptotic genes, Insulin like growth factor-1 (IGF1) receptor, oxytocin receptor, αS1, αS2, and β casein genes were analyzed at 1, 2, 4, and 8 d after differentiation. Results The proliferation of MAC-T cells with high-glucose treatment was seen to be significantly higher. Expression of apoptotic genes was not affected in any group. However, expression levels of the mammary development related gene (IGF1 receptor) and lactation related gene (oxytocin receptor) were significantly higher in the low-glucose group. Expressions of αS1-casein, αS2-casein, and β-casein were also higher in the low-glucose treated group as compared to that in the no-glucose and high-glucose groups. Conclusion The results demonstrated that although a high-glucose environment increases cell proliferation in MAC-T cells, a low-glucose treatment to MAC-T cells induces higher expression of casein genes. Our results suggest that the MAC-T cells may be used as an in vitro model to analyze mammary cell development and lactation connected with precise biological effects.

Germ cell-specific apoptosis by extracellular clusterin in cryptorchid dog testes

Mammalian testes are maintained at a relatively lesser temperature than the abdominal region so that normal spermatogenesis can occur. Germ cell apoptosis has resulted in heat-damaged testes that occurs as a result of cryptorchidism, but the mechanism is not yet fully understood. To elucidate the cause of germ-cell death by cryptorchidism, cryptorchidism was surgically induced in dog testes and histological and molecular analyses were performed. Histological data indicated that the seminiferous tubules of cryptorchid testes and epididymis contained fewer germ cells. Total RNA sequencing was performed to screen for overexpressed genes in cryptorchid dog testes. Clusterin RNA was in greater abundance (approximately 12.8-fold) in cryptorchid testes than in normal testes. In addition, cleaved caspase-3 and -8 were detected in greater abundance in cryptorchid dog testes. Real time RT-PCR and western blotting analysis indicated there was a greater abundance of clusterin in cryptorchid dog testes. Furthermore, clusterin was detected in extracellular regions of cryptorchid dog testes during the 4 weeks after surgery. Thus, germ-cell specific apoptosis and expression of clusterin genes occur with a resulting presence of this protein in extracellular regions of cryptorchid dog testes. This result will facilitate further study of spermatogenesis and the specific mechanisms by which cryptorchidism results in male infertility.

Dose-dependent effects of busulfan on dog testes in preparation for spermatogonial stem cell transplantation

Successful male germ cell transplantation requires depletion of the host germ cells to allow efficient colonization of the donor spermatogonial stem cells. Although a sterilizing drug, busulfan, is commonly used for the preparation of recipient models before transplantation, the optimal dose of this drug has not yet been defined in dogs. In this study, 1-year-old mongrel dogs were intravenously injected with three different concentrations of busulfan (10, 15, or 17.5 mg/kg). Four weeks after busulfan treatment, no fully matured spermatozoa were detected in any of the busulfan-treated groups. However, small numbers of PGP9.5-positive spermatogonia were detected in all treatment groups, although no synaptonemal complex protein-3-positive spermatocytes were detected. Of note, acrosin-positive spermatids were not detected in the dogs treated with 15 or 17.5 mg/kg busulfan, but were detected in the other group. Eight weeks after busulfan treatment, the dogs treated with 10 mg/kg busulfan fully recovered, but those in the other groups did not. PGP9.5-positive spermatogonia were detected in the 10 mg/kg group, and at a similar level as in the control group, but these cells were rarely detected in the 15 and 17.5 mg/kg groups. These results suggest that a dose of 15-17.5 mg/kg is optimal for ablative treatment with busulfan to prepare the recipient dogs for male germ cell transplantation. At least eight weeks should be allowed for recovery. The results of this study might facilitate the production of recipient dogs for male germ cell transplantation and can also contribute to studies on chemotherapy.