小鼠精原干细胞冻存后体外培养

目的:研究冷冻后精原干细胞体外培养时的生物学行为.方法:体外培养冻存后的6日龄小鼠生精上皮细胞,并利用碱性磷酸酶活性及细胞形态,检测其中的精原干细胞.结果:当有BRL饲养层时,冻存后的精原细胞在贴壁、存活及增殖等生物学行为方面与新分离的精原细胞均无明显不同.培养25～30 d,培养体系中仍保留有少量精原干细胞及其最初几代分化细胞.结论:冷冻保存后的精原干细胞能在BRL细胞饲养层上正常地贴壁、生长和分裂.     

一种简便的小鼠精原干细胞分离培养方法

采用一步酶消化法分离小鼠精原干细胞,比较α-MEM、DMEM培养基对体外培养的精原干细胞生长状态的影响,对精原干细胞集落进行形态观察、碱性磷酸酶(alkaline phosphatase,AKP)染色和免疫组化鉴定,并诱导精原干细胞向精子细胞分化。结果显示,以小鼠胚胎成纤维细胞作为饲养层,用α-MEM培养的精原干细胞集落较大且呈葡萄串状或念珠状,细胞状态较好;小鼠精原干细胞集落的AKP染色阳性呈紫红色;在红色荧光下精原干细胞集落的Oct-4核蛋白表达为阳性、膜蛋白c-Kit、β_1-integrin和Gfrα-1表达为阳性;精原干细胞经维甲酸(all-trans-retinoic-acid,RA)诱导可初步分化成精子样细胞。因此,采用一步酶消化法能够分离小鼠精原干细胞,α-MEM更适合小鼠精原干细胞体外培养。     

山羊精原干细胞的鉴定及培养体系优化的研究

该研究优化了山羊精原干细胞(goat spermatogonial stem cells,g SSCs)培养体系,使山羊精原干细胞能在体外长期培养,维持自我更新的能力并保持未分化状态。取3~5月龄山羊睾丸,采用两步酶消法结合差速贴壁方法得到山羊精原干细胞悬液,分别通过形态学观察、碱性磷酸酶(alkaline phosphatase,AKP)染色、特异基因表达及蛋白质水平的分析对培养的细胞进行鉴定;并以山羊睾丸支持细胞(goat sertoli cells,g SCs)、小鼠胚胎成纤维细胞(mouse embryonic fibroblasts,MEFs)和层黏连蛋白(laminin,L)为饲养层,观察饲养层对山羊精原干细胞体外增殖的影响。结果表明,山羊精原干细胞体外增殖形成克隆簇,AKP染色呈阳性。经RT-PCR检测,Oct-4、C-myc、Cyclin D1、Ngn3和TERT等干细胞特异基因均有表达。细胞免疫组化结果显示,Oct-4、SSEA-1、α6-integrin、Vasa和Thy-1蛋白质呈阳性。克隆簇统计显示,在山羊睾丸支持细胞上形成的山羊精原干细胞(goat spermatogonial stem cells,g SSCs)克隆数与其他两组比较差异显著(P0.05)。山羊睾丸支持细胞饲养层上的精原干细胞可在体外传3~4代,培养时间为2个月。结果证明,通过两步酶消法和差速贴壁法可以分离获得山羊精原干细胞,且山羊睾丸支持细胞能够促进g SSCs的增殖。     

人骨髓基质细胞对精原干细胞体外增殖的影响研究

精原干细胞是精子形成的原始细胞,在睾丸组织中的含量极低,而体外有效扩增方法的选择对其移植治疗和抗生育研究十分重要。本实验选用人骨髓基质细胞代替传统饲养层培养人精原干细胞,探讨精原干细胞能否在该饲养层上增殖的可能机制,为人精原干细胞培养提供实验方法和技术指导。骨髓基质饲养层的制备：无菌分离流产5～8月胎儿股骨,     

不同年龄小鼠精原干细胞系的建立

精原干细胞（spennatogonial stem cells,SSCs）是雄性动物体内能进行终生自我更新并能将亲代基因遗传给予子代的一类细胞。不同年龄段的小鼠有不同的建系方法。6-7d幼鼠,可以用差异贴壁或直接贴壁法;5-6周成年鼠,一般采用差异贴壁法;31周老年鼠,最好种于饲养层细胞上。通过对精原干细胞系的甲基化和特异基因分析以及睾丸体内移植验证分析,成功建立了具有功能的不同年龄段的小鼠精原干细胞系。     

过表达水牛睾丸FGF2基因维持水牛精原细胞的体外培养

水牛睾丸支持细胞(Sertoli cells)是环绕在精原干细胞(spermatogonial stem cells,SSCs)周围的一类体细胞,为SSCs增殖提供物理支持及稳定的环境,同时参与血睾屏障形成.支持细胞可分泌FGF2,从而提高SSCs存活和增殖.至今为止,水牛SSCs培养体系仍然面临许多挑战,推测内源性的...     

昆明白小鼠胚胎干细胞分离与体外培养

为探索昆明白小鼠胚胎干细胞建系方法,将受孕4.5天的昆明白小鼠囊胚用免疫手术法去除滋胚层,然后将内细胞团(ICM)接种于胎鼠成纤维细胞饲养层上培养,形成的胚胎干细胞样集落用胰蛋白酶-EDTA消化法传代,培养后进行相差显微镜观察及碱性磷酸酶染色。结果饲养层上生长的ICM细胞呈典型的ES样细胞集落,传至第8代碱性磷酸酶染色呈强阳性。实验表明免疫手术法适用于昆明白小鼠ES细胞建系,获得的细胞集落具有ES细胞的主要生物学性状。     

CREG低表达饲养层STO细胞的建立

目的:为阐明E1A激活基因阻遏子(Cellular repressor of E1A-stimulated genes,CREG)对胚胎干细胞(Embryonic stem cell,ESC)自我更新的影响及作用机制,本研究拟通过RNA干扰方法建立CREG低表达的饲养层STO细胞,为深入研究奠定基础。方法:用Western Blot方法检测饲养层细胞系STO及ESC细胞系R1中CREG基因的表达。利用Lipofectamine 2000向STO细胞中分别转染RNA干扰空对照载体,含有无意义随机序列的对照载体以及含有4种不同CREG干扰序列的载体。用1.0μg/ml嘌呤霉素筛选1 w,荧光显微镜下挑取绿色荧光蛋白表达较高的克隆进行扩增。Western Blot方法鉴定CREG基因干扰效率,获得CREG表达最低的饲养层细胞克隆。将ESC R1接种到该克隆上,不添加白血病抑制因子,连续培养3代,用碱性磷酸酶染色判断其是否分化。结果:R1几乎不表达CREG,而STO细胞高表达CREG。Western Blot结果证实筛选到的STO克隆3A干扰效果最好,达到85%。在不添加白血病抑制因子的情况下,碱性磷酸酶染色表明R1细胞在该株饲养层细胞上连续培养3代后未见明显分化。结论:成功获得CREG低表达饲养层STO细胞,为深入探讨CREG对ESC自我更新的作用及机制奠定了基础。     

牛精原干细胞体外分化潜能的分析

家畜精原干细胞操作的核心技术是精原干细胞(spermatogonial stem cells,SSCs)的长期培养。至今家畜精原干细胞的长期培养方法还没有完善。其中的一个原因是缺乏简便有效的家畜精原干细胞生物活性鉴定手段。该研究的目的是建立一种牛精原干细胞生理潜能的体外分析方法,用于体外培养的牛精原干细胞的生物活性鉴定。首先培养牛精原干细胞,进而用干细胞因子(stem cell factor,SCF)对体外长期培养的牛精原干细胞进行诱导分化。在诱导分化过程中对细胞进行显微观察,并且用免疫荧光染色法鉴定分化的细胞。观察结果显示,经过诱导培养8 d后,牛精原干细胞形态发生了明显改变;细胞的运动行为显示出精母细胞特有的特征。免疫荧光染色结果显示,分化的细胞表达精母细胞的标记基因Scp3。上述结果例证了体外培养的牛精原干细胞具有分化为精母细胞的潜能。该研究建立了牛SSCs体外诱导分化的分析方法,用于鉴定体外培养的牛SSCs的生理潜能。但是体外诱导培养条件不能满足牛SSCs减数分裂的全部要求,导致出现一些不完全符合精母细胞特征的现象。诱导分化培养液尚需改进。     

小鼠精原干细胞与胚胎干细胞样细胞

近年来,通过培养小鼠精原干细胞(spermatogonial stem cells,SSCs)获得了胚胎干细胞样细胞(,embryonic stem cell-like cells,ES样细胞).这些研究表明小鼠精原干细胞不仅具备特异分化为精子的干细胞潜能,而且具备胚胎干细胞(embryonic stem cell,ES)分化为三胚层的多向分化潜能.因此.这将有助于研究干细胞的分化调控机制,并且这些研究成果延伸至人类精原干细胞,也将为再生医学获取特殊的胚胎干细胞样细胞或特异分化的精子细胞开辟了蹊径.     

Differentiation of spermatogonial stem cell-like cells from murine testicular tissue into haploid male germ cells in vitro

In vitro differentiation of spermatogonial stem cells (SSCs) promotes the understanding of the mechanism of spermatogenesis. The purpose of this study was to isolate spermatogonial stem cell-like cells from murine testicular tissue, which then were induced into haploid germ cells by retinoic acid (RA). The spermatogonial stem cell-like cells were purified and enriched by a two-step plating method based on different adherence velocities of SSCs and somatic cells. Cell colonies were present after culture in M1-medium for 3 days. Through alkaline phosphatase, RT-PCR and indirect immunofluorescence cell analysis, cell colonies were shown to be SSCs. Subsequently, cell colonies of SSCs were cultured in M2-medium containing RA for 2 days. Then the cell colonies of SSCs were again cultured in M1-medium for 6–8 days, RT-PCR and indirect immunofluorescence cell analysis were chosen to detect haploid male germ cells. It could be demonstrated that 10⁻⁷ mol l⁻¹ of RA effectively induced the SSCs into haploid male germ cells in vitro.     

Maintenance of mouse male germ line stem cells in vitro

The proliferation and differentiation of a stem cell are regulated intrinsically by the stem cell and extrinsically by the stem cell niche. Elucidation of regulatory mechanisms of spermatogonial stem cells (SSCs), the stem cell of the postnatal male germ line, would be facilitated by in vitro studies that provide a defined microenvironment reconstituted ex vivo. We analyzed the effect of in vitro environment on the maintenance of adult and immature SSCs in a 7-day culture system. Although the number of adult and immature SSCs decreased in a time-dependent manner, nearly one in four stem cells (24%) could be maintained in vitro for 7 days. Stem cell maintenance was enhanced by coculture with OP9 bone marrow stroma or L fibroblast cell lines, addition of glial cell line-derived neurotrophic factor, or utilization of specific culture medium. In contrast, coculture with TM4 or SF7 Sertoli cell lines and addition of activin A or bone morphogenetic protein 4 (BMP4) reduced stem cell maintenance in vitro. Only 4% of the stem cells remained when cultured with TM4 cells or activin A, and 6% remained when cultured with SF7 cells or BMP4. These results lead to the hypothesis that suppression of germ cell differentiation improves in vitro maintenance of SSCs by interrupting the unidirectional cascade of spermatogenesis and blocking stem cell differentiation.     

食蟹猴精原干细胞体外培养体系的初步建立

为了掌握食蟹猴(Macaca fascicularis)精原于细胞(spermatogonial stem cells,SSCs)体外培养生长特性,并建立其培养体系.手术法获得幼年期食蟹猴单侧睾丸,改良的两步酶消化法获得其细胞悬液,添加特定培养液进行体外培养,以碱性磷酸酶(AKP)染色鉴定培养细胞,并评价不同饲养层细胞...     

Effects of different feeder layers on short-term culture of prepubertal bovine testicular germ cells in-vitro

Spermatogonial stem cells (SSCs) are exceptional adult stem cells that transfer genes to new generations. This behavior makes them unique cells for the production of transgenic farm animals. However, this goal has been hampered by their spontaneous differentiation during in vitro culture. Therefore, the objective of this study was the evaluation of the effects of different feeders on in vitro short-term culture of prepubertal bovine testicular germ cells. The isolated cell suspensions containing SSCs were enriched by Bovine serum albumin (BSA) and gelatin and were cultured in the presence of Glial-derived neurotrophic factor (GDNF), Epidermal Growth Factor (EGF) and basic Fibroblastic Growth Factor (bFGF). After 7 d of culture, colonies were harvested and cultured on four different feeders, including SIM mouse embryo-derived thioguanine and ouabain resistant (STO), mouse embryonic fibroblast, bovine Sertoli cells (BSC) and on a laminin-coated plate. The number and area of colonies were measured at seven, 11 and 14 d post-culture. The expression of germ cells markers was detected using immunofluorescence and flow cytometry analyses on day 7, and quantitative real-time PCR at 14 d post-culture. Immunocytochemical staining revealed that colonies were positive for Dolichos biflorus agglutinin (DBA), Thy-1, Oct-4, c-ret, α6-integrin, β1-integrin and negative for c-kit. In addition, the number and area of those colonies formed on the STO feeder were significantly greater than the other groups. Relative expressions of Thy-1 in the STO and in BSC groups were significantly higher than other groups but expression of Oct-4 was highest in the laminin group compared to other groups. In conclusion, STO might be a suitable feeder layer for in vitro propagation of bovine testicular germ cells.     

Culture conditions and single growth factors affect fate determination of mouse spermatogonial stem cells

Cell fate determination between self-renewal or differentiation of spermatogonial stem cells (SSCs) in the testis is precisely regulated to maintain normal spermatogenesis. However, the mechanisms underlying the process remain elusive. To address the problem, we developed a model SSC culture system, first, by establishing techniques to obtain enriched populations of stem cells, and second, by establishing a serum-free culture medium. Flow cytometric cell sorting and the SSC transplantation assay demonstrated that Thy-1 is a unique surface marker of SSCs in neonatal, pup, and adult testes of the mouse. Although the surface phenotype of SSCs is major histocompatibility complex class I(-) Thy-1(+) alpha 6-integrin(+) alpha v-integrin(-/dim) throughout postnatal life, the most enriched population of SSCs was obtained from cryptorchid adult testes by cell-sorting techniques based on Thy-1 expression. This enriched population of SSCs was used to develop a culture system that consisted of serum-free defined medium and STO (SIM mouse embryo-derived thioguanine and ouabain resistant) feeders, which routinely maintained stem cell activity for 1 wk. Combining the culture system and the transplantation assay provided a mechanism to study the effect of single growth factors. A negative effect was demonstrated for several concentrations of basic fibroblast growth factor and leukemia inhibitory factor, whereas glial cell line-derived neurotrophic factor and stem cell factor appeared to have a positive effect on stem cell maintenance. The stem cell enrichment strategies and the culture methods described provide a reproducible and powerful assay system to establish the effect of various environmental factors on SSC survival and replication in vitro.     

Deriving multipotent stem cells from mouse spermatogonial stem cells: a new tool for developmental and clinical research

In recent years, embryonic stem (ES) cell-like cells have been obtained from cultured mouse spermatogonial stem cells (SSCs). These advances have shown that SSCs can transition from being the stem cell-producing cells of spermatogenesis to being multipotent cells that can differentiate into derivatives of all three germ layers. As such, they offer new possibilities for studying the mechanisms that regulate stem cell differentiation. The extension of these findings to human SSCs offers a route to obtaining personalized ES-like or differentiated cells for use in regenerative medicine. Here, we compare the different approaches used to derive ES-like cells from SSCs and discuss their importance to clinical and developmental research.     

Effects of different Sertoli cell types on the maintenance of adult spermatogonial stem cells in vitro

Spermatongonial stem cells (SSCs) are unique testis cells that are able to proliferate, differentiate, and transmit genetic information to the next generation. However, the effect of different Sertoli cell types on the expression of specific SSC genes is not yet well understood. In this study, we compare the in vitro effect of adult Sertoli cells, embryonic Sertoli cells, and TM4 (a Sertoli cell line) as feeder layers on the expression of SSC genes. SSCs were isolated from the testis of adult male mice and purified by differential plating. Following enrichment, SSCs were cultivated for 1 and 2 wk in the presence of various feeders. The expression of SSC-specific genes (Mvh, ZBTB, and c-kit) was evaluated by real-time polymerase chain reaction. Our results revealed that expression of the specific SSC genes was significantly higher in the embryonic Sertoli cells after 1 and 2 wk compared to the adult Sertoli cells and the TM4 group. Our finding suggest that co-culturing of SSCs with embryonic Sertoli cells is helpful for in vitro cultivation of SSCs and might improve the self-renewal of these stem cells.     

Use of human amniotic epithelial cells as a feeder layer to support undifferentiated growth of mouse spermatogonial stem cells via epigenetic regulation of the Nanog and Oct-4 promoters

Spermatogonial stem cells (SSCs) are defined by unique properties like other stem cells. However, there are two major challenges: long-term cultivation of normal SSCs into stable cell lines and maintaining the SSCs as undifferentiated and capable of self-renewal. Here, we compared different culture methods for mouse SSCs isolated and cultured from testicular tissue. We found that human amniotic epithelial cells (hAECs) can behave as feeder cells, allowing mouse SSCs to maintain a high level of alkaline phosphatase (AP) activity when cultured long-term. Also, we observed that expression of Nanog, Oct-4 and other important stem cells markers were higher in mouse SSCs cultured on hAECs compared to those cultured on MEF or without any feeder cells. Furthermore, we demonstrated that the CpG islands of the Nanog and Oct-4 promoters were hypomethylated in cells cultured on hAECs. In addition, mouse SSCs cultured on hAECs exhibited higher levels of H3AC and H3K4Me3 in the Nanog and Oct-4 promoters than those cultured on MEF or without feeder cells. Taken together, these results suggest that the hAEC-induced epigenetic modifications at the Nanog and Oct-4 locus could be a key mechanism for maintaining mouse SSCs in an undifferentiated state capable of self-renewal.     

小鼠精原干细胞在三种培养基中的生长行为

目的：建立小鼠精原干细胞（SSCs）的体外长期培养体系。方法：用分别添加了等量的胶质细胞源神经营养因子（GDNF）、可溶性GFRα1和hFGF的DMEM／F12、KSR和StemPro-34 SFM三种无血清培养基和MEF饲养层分别培养经差异贴壁分选富集的小鼠SSCs,通过形态观察、标志基因的RT-PCR和免疫细胞化学分析检测其SSCs本原。结果：DMEM／F12与KSR可支持小鼠SSCs在体外存活6-7d,而StemPro-34 SFM能能维持SSCs体外增值一个月。结论：StemPro-34 SFM支持小鼠SSCs的体外增殖。