Production of Transgenic Mice by Type-A Spermatogonia-Mediated Gene Transfer

Type-A spermatogonia first appear at between 3-7 d postnatally in mice and are the only immortalized diploid cells that reproduce in adulthood in these animals. In our current study, we explored the feasibility of producing stable transgenic mice using these cells. Enhanced pEGFP-N1 plasmids were suspended in ExGen500 transfection reagent and injected at different angles into the testes of 7-d-old male ICR mice. The resulting type-A spermatogonia-mediated gene transfer （TASMGT） mice were then mated with normal females at different stages of sexual maturity （6, 12, and 24 wk）. The integration and expression of the introduced EGFP gene was evaluated in the F1 transgenic offspring by PCR and Southern blotting analysis. The foreign gene integration rates for a low-dose group （15 μL gene suspension injected into each testis） and a high-dose group （30 μL suspensions injected） at the three stages of female sexual maturity tested were 11.76% （2/17）, 14.29% （3/21）, and 11.11% （2/18）, and 5% （1/20）, 5.56% （1/18）, and 0 （0/17）, respectively. The average integration rates for these two dose groups were 12.5% （7/56） and 3.64% （2/55）, respectively, which was a significant difference （P0.05）. Semi-quantitative RT-PCR analysis further showed that the introduced GFP gene was expressed in 3/9 integration mice. In addition, GFP expression was observed in the sperm cells from the TASMGT mice, and also in the embryos and F2 pups from the F1 generation transgenic mice. Hence, although the foreign gene integration rate for TASMGT is not high and the transgenic offspring show as yet unexplained defects, our results indicate that this method is a potentially feasible and reproducible new approach to creating transgenic mice.

Downregulation of Col lal induces differentiation in mouse spermatogonia

Col la I （one of the subunit of collagen type I） is a collagen, which belongs to a family of extracellular matrix （ECM） proteins that play an important role in cellular proliferation and differentiation. However, the role of Col lal in spermatogenesis, especially in the control of proliferation and differentiation of spermatogonial stem cells （SSCs）, remains unknown. In this study, we explored effects of downregulation of Collal on differentiation and proliferation of mouse spermatogonia. Loss-of-function study revealed that Oct4 and Plzf, markers of SSC self-renewal, were significantly decreased, whereas the expression of c-kit and haprin, hallmarks of SSC differentiation, was enhanced after Col la I knockdown. Cell cycle analyses indicated that two-thirds of spermatogonia were arrested in S phase after Collal knockdown. In vivo experiments, DNA injection and electroporation of the testes showed that spermatogonia self-renewal ability was impaired remarkably with the loss-of-function of Collal. Our data suggest that silencing of Collal can suppress spermatogonia self-renewal and promote spermatogonia differentiation.

Gene expression dynamics during the gonocyte to spermatogonia transition and spermatogenesis in the domestic yak

Background:Spermatogenesis is a cellular differentiation process that includes three major events:mitosis of spermatogonia,meiosis of spermatocytes and spermiogenesis.Steady-state spermatogenesis relies on functions of spermatogonial stem cells(SSCs).Establishing and maintaining a foundational SSC pool is essential for continued spermatogenesis in mammals.Currently,our knowledge about SSC and spermatogenesis is severely limited in domestic animals.Results:In the present study,we examined transcriptomes of testes from domestic yaks at four different stages(3,5,8 and 24 months of age)and attempted to identify genes that are associated with key developmental events of spermatogenesis.Histological analyses showed that the most advanced germ cells within seminiferous tubules of testes from 3,5,8 and 24 months old yaks were gonocytes,spermatogonia,spermatocytes and elongated spermatids,respectively.RNA-sequencing(RNA-seq)analyses revealed that 11904,4381 and 2459 genes were differentially expressed during the gonocyte to spermatogonia transition,the mitosis to meiosis transition and the meiosis to post-meiosis transition.Further analyses identified a list of candidate genes than may regulate these important cellular processes.CXCR4,a previously identified SSC niche factor in mouse,was one of the up-regulated genes in the 5 months old yak testis.Results of immunohistochemical staining confirmed that CXCR4 was exclusively expressed in gonocytes and a subpopulation of spermatogonia in the yak testis.Conclusions:Together,these findings demonstrated histological changes of postnatal testis development in the domestic yak.During development of spermatogonial lineage,meiotic and haploid germ cells are supported by dynamic transcriptional regulation of gene expression.Our transcriptomic analyses provided a list of candidate genes that potentially play crucial roles in directing the establishment of SSC and spermatogenesis in yak.

Sertoli cell and spermatogonial development in pigs

Background:Spermatogenesis is an intricate developmental process during which undifferentiated spermatogonia,containing spermatogonial stem cells(SSCs),undergo self-renewal and differentiation to generate eventually mature spermatozoa.Spermatogenesis occurs in seminiferous tubules within the testis,and the seminiferous tubules harbor Sertoli and germ cells.Sertoli cells are an essential somatic cell type within the microenvironment that support and steer male germ cell development,whereas spermatogonia are the primitive male germ cells at the onset of spermatogenesis.While the developmental progression of Sertoli cells and spermatogonia has been well established in mice,much less is known in other mammalian species including pigs.Results:To acquire knowledge of Sertoli cell and spermatogonial development in pigs,here we collected as many as nine ages of Duroc porcine testes from the neonate to sexual maturity,i.e.,testes from 7-,30-,50-,70-,90-,110-,130-,150-and 210-day-old boars,and performed histological and immunohistochemical analyses on testis sections.We first examined the development of spermatogenic cells and seminiferous tubules in porcine testes.Then,by immunofluorescence staining for marker proteins(AMH,SOX9,DBA,UCHL1,VASA,KIT,Ki67 and/or PCNA),we delved into the proliferative activity and development of Sertoli cells and of spermatogonial subtypes(pro-,undifferentiated and differentiating spermatogonia).Besides,by immunostaining forβ-catenin and ZO-1,we studied the establishment of the blood-testis barrier in porcine testes.Conclusions:In this longitudinal study,we have systematically investigated the elaborate Sertoli cell and spermatogonial developmental patterns in pigs from the neonate to sexual maturity that have so far remained largely unknown.The findings not only extend the knowledge about spermatogenesis and testicular development in pigs,but also lay the theoretical groundwork for porcine breeding and rearing.

17beta-estradiol stimulates proliferation of spermatogonia in experimental cryptorchid mice

Aim： To investigate whether estrogen stimulates the proliferation of spermatogonia or induces spermatogenesis in cryptorchid mice. Methods： Mice were surgically rendered cryptorchid, then treated with different doses of 17β- estradiol （E2） s.c. once a day. Mice were killed at sexual maturity （45 days of age）, and histological analysis and inununofluorescence were performed. Serum follicle stimulating hormone （FSH）, estradiol, testosterone and luteinizing hormone （LH） were measured. Results： Low doses of E2 had no notable effect on spermatogonia, but at higher doses, E2 stimulated the proliferation of spermatogonia. Conclusion： E2 has a dose-related mitogenic effect on spermatogonia.

Isolation of Subtype Spermatogonia in Juvenile Rats

The present study was aimed at finding an effective method to isolate and purify the subtype of type A spermatogonial stem cells （SSCs） in juvenile rats. Testes from 9-days-old rats were used to isolate germ cells by using two-step enzymatic digestion. The expression of c-kit in the testes of the rats was immunohistochemically detected. After isolation, cell suspension was enriched further by discontinuous density gradient centrifugation. Then type A1-A4 spermatogonia was isolated from the purified spermatogonia with c-kit as the marker by using fluorescence-activated cell sorting （FACS）. Electron microscopy was used to observe their ultrastructure. Finally, highly purified and viable subtype of SSCs was obtained. Cells separation with discontinuous density gradient centrifugation significantly increased the concentration of c-kit positive cells [（18.65±1.69）% after the centrifugation versus （3.16±0.84）% before the centrifugation, P〈0.01]. Furthermore, the recovery and viability were also high [（65.9±1.24）% and （85.6±1.14）%]. It is concluded that FACS with c-kit as the marker in combination with discontinuous density gradient centrifugation can well enrich type A1-A4 spermatogonia from the testes of 9-days-old rats.

Production of functional sperm from in vitro-cultured premeiotic spermatogonia in a marine fish

In vitro production of functional gametes can revolutionize reproduction by reducing generation intervals and accelerating genetic breeding in aquaculture,especially in fish with relatively long generations.Nevertheless,functional sperm production from in vitro-cultured spermatogonia remains a challenge in most aquaculture fish.In this study,we isolated and characterized premeiotic spermatogonia from marine four-eyed sleepers(Bostrychus sinensis),which are prone to ovotesticular or sterile testicular development,and induced the differentiation of the spermatogonia into flagellated sperm in a three-dimensional(3D)culture system.Artificial insemination indicated that the in vitro-derived sperm were capable of fertilizing mature oocytes to develop into normal larvae.Furthermore,melatonin significantly promoted spermatogonia proliferation and differentiation through the ERK1/2 signaling pathway,and thus increased the efficiency in functional sperm production.The 3D culture system and resulting functional sperm hold great promise for improving the genetic breeding of aquaculture fish.

Ionizing Radiation-Induced RPL23a Reduction Regulates Apoptosis via RPL11-MDM2-p53 Pathway in Mouse Spermatogonia

Objective The expression patterns of ribosomal large subunit protein 23 a(RPL23 a)in mouse testes and GC-1 cells were analyzed to investigate the potential relationship between RPL23 a expression and spermatogonia apoptosis upon exposure to X-ray.Methods Male mice and GC-1 cells were irradiated with X-ray,terminal dUTP nick end-labelling(TUNEL)was performed to detect apoptotic spermatogonia in vivo.Apoptotic rate and cell cycle phase of GC-1 cells were analyzed with flow cytometry.Protein interactions were detected by Immunoprecipitation and protein localization as studied by immunofluorescence.Immunoblotting and real-time PCR were applied to analyze to protein and gene expression.Results Ionizing radiation(IR)increased spermatogonia apoptosis,the expression of RPL11,MDM2 and p53,and decreased RPL23 a expression in mice spermatogonia in vivo and in vitro.RPL23 a knockdown weakened the interaction between RPL23 a and RPL11,leading to p53 accumulation.Moreover,knockdown and IR decreased RPL23 a that induces spermatogonia apoptosis via RPL23 a-RPL11-MDM2-p53 pathway in GC-1 cells.Conclusion These results suggested that IR reduced RPL23 a expression,leading to weakened the RPL23 a-RPL11 interactions,which may have activated p53,resulting in spermatogonia apoptosis.These results provide insights into environmental and clinical risks of radiotherapy following exposure to IR in male fertility.The graphical abstract was available in the web of www.besjournal.com.

scRNA-seq reveals that origin recognition complex subunit 6 regulates mouse spermatogonial cell proliferation and apoptosis via activation of Wnt/β-catenin signaling

The regulation of spermatogonial proliferation and apoptosis is of great significance for maintaining spermatogenesis.The single-cell RNA sequencing(scRNA-seq)analysis of the testis was performed to identify genes upregulated in spermatogonia.Using scRNAseq analysis,we identified the spermatogonia upregulated gene origin recognition complex subunit 6(Orc6),which is involved in DNA replication and cell cycle regulation;its protein expression in the human and mouse testis was detected by western blot and immunofluorescence.To explore the potential function of Orc6 in spermatogonia,the C18-4 cell line was transfected with control or Orc6 siRNA.Subsequently,5-ethynyl-2-deoxyuridine(EdU)and terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)assays,flow cytometry,and western blot were used to evaluate its effects on proliferation and apoptosis.It was revealed that ORC6 could promote proliferation and inhibit apoptosis of C18-4 cells.Bulk RNA sequencing and bioinformatics analysis indicated that Orc6 was involved in the activation of wingless/integrated(Wnt)/β-catenin signaling.Western blot revealed that the expression ofβ-catenin protein and its phosphorylation(Ser675)were significantly decreased when silencing the expression of ORC6.Our findings indicated that Orc6 was upregulated in spermatogonia,whereby it regulated proliferation and apoptosis by activating Wnt/β-catenin signaling.

Successful transplantation of cryopreserved spermatogonia in Sebastes schlegelii:A simple and suitable alternative approach for conservation of viviparous fish

Black rockfish(Sebastes schlegelii)is one of the most important marine economic viviparous fishes.Recently,germplasm degradation and genetic diversity reduction have occurred due to overfishing and long-term artificial breeding.Germ cell transplantation combined with cryopreservation may be an alternative way to protect genetic resources.However,in viviparous fish that undertake fertilization and embryo development in vivo,transplantation is more difficult than in oviparous fish,including selection of transplantation stage,isolation of germ stem cells,and preparation of sterile recipients.This seriously restricts the development of viviparous transplantation.Therefore,in this study,we aimed to explore a transplantation method suitable for these species.Donor cells were isolated from cryopreserved whole testes of 300–400​g male Sebastes schlegelii in May,labeled by PKH26,and intra-peritoneally transplanted into allogeneic larvae at 5–10 days post-birth.Subsequently,the development of donor-derived cells in recipients were continuously detected by fluorescence labeling,histology,microsatellite markers,and fecundity tests.The results showed that donors were rich in spermatogonia(75%)and recipients maintained a high survival rate after transplantation,with a rate of>20%at sexual maturity.Further,donor-derived cells successfully migrated(100%),colonized,and incorporated into the developing recipient gonad(93.33%).Finally,transplanted recipients could normally develop and differentiate into male and female individuals,with donor-derived gametes found in 65.38%of mature recipients.In the present study,we first establish a simple and suitable transplantation method for Sebastes schlegelii using immature males and specific larvae,which will serve as a promising tool in the protection of germplasm resources for this transplantation-restricted marine viviparous species.

PLZF的克隆及其对犏牛未分化精原细胞的增殖作用

【目的】犏牛作为牦牛与黄牛的种间杂交产物,具有优良的生产性能,但其杂种优势的进一步应用却受限于犏牛雄性不育。通过克隆犏牛PLZF,明确其在犏牛和牦牛睾丸组织和未分化精原细胞中的差异表达,并进一步揭示过表达该基因对犏牛未分化精原细胞活性的影响。为阐明犏牛生精停滞的作用机制提供理论基础。【方法】以24月龄公麦洼牦牛和F1代公犏牛为实验动物,通过RT-PCR法克隆得到了犏牛PLZF的CDS序列,并进行了生物信息学分析;通过RT-qPCR法分析PLZF在犏牛和牦牛睾丸组织中的差异表达;采用同源重组的方法构建了PLZF的表达载体,并利用RT-qPCR检测了PLZF过表达效率及其下游靶基因的表达;通过PDT、CCK-8、EdU和免疫荧光检测了过表达PLZF对犏牛未分化精原细胞增殖活性的影响。【结果】克隆获得了犏牛PLZF的CDS区,并通过生物信息学分析发现该基因编码的蛋白序列不包含跨膜结构域和信号肽序列,其三级结构以α螺旋和无规卷曲为主。系统进化树分析表明犏牛PLZF与黄牛PLZF的亲缘关系更近。三级结构预测发现,虽然犏牛、牦牛和黄牛的PLZF蛋白三级结构高度相似,但牦牛PLZF蛋白在531—540位氨基酸处与犏牛和黄牛有较大差异。RT-qPCR发现,PLZF在犏牛睾丸组织和未分化精原细胞中的表达均显著低于牦牛(P<0.05),而在犏牛未分化精原细胞中过表达PLZF后,该基因的表达上调了13.8倍(P<0.01),且能显著增加犏牛未分化精原细胞的增殖活性(P<0.05),表明PLZF表达下调影响了犏牛未分化精原细胞增殖活性。此外,过表达PLZF后,犏牛未分化精原细胞中与增殖相关的基因(Etv5、Bcl6b、Pcna和c-fos)全部显著上调(P<0.05),与分化相关的基因(Stra8、Kit、Dmrt1和Sohlh2)全部显著下调(P<0.05),表明PLZF通过上调增殖相关基因、下调分化相关基因的表达促进犏牛未分化精原细胞增殖。【结论】PLZF在犏牛未分化精原细胞中表达异常降低了犏牛未分化精原细胞增殖活性,导致其数量减少,影响了犏牛的精子发生。本试验为进一步阐明犏牛生精停滞的作用机制提供了理论基础,并为解决犏牛雄性不育问题提供了新的思路。

三氯异氰尿酸通过诱导氧化应激和铁死亡抑制精原细胞增殖

目的探索三氯异氰尿酸(TCCA)对小鼠睾丸精原细胞GC-1氧化应激和DNA甲基化的影响。方法以TCCA 0(细胞对照),97,194和387μmol·L^(-1)处理GC-1细胞24 h;CCK-8法检测细胞存活率;Hoechst 33342染色检测各组细胞形态和凋亡率;流式法检测细胞周期;实时荧光定量PCR(RT-qPCR)检测细胞凋亡相关基因Bax和Fas、氧化应激相关基因线粒体超氧化物歧化酶(SOD2)、铁死亡相关基因谷胱甘肽过氧化酶4(GPX4)、核因子红细胞2相关因子2(Nrf2)、溶质载体家族7成员11(SLC7A11)、二氢乳清酸脱氢酶(DHODH)、DNA甲基化转移酶3A(DNMT3A)和DNA甲基转移酶3L(DNMT3L)mRNA表达水平;Griess法测定GC-1细胞一氧化氮(NO)含量,比色法测定丙二醛(MDA)水平;DCFH-DA荧光探针法测定GC-1细胞活性氧(ROS)水平,DNTB比色法测定还原型谷胱甘肽(GSH)含量,WST-8法测定还原型辅酶Ⅱ(NADPH)含量。结果与细胞对照组相比,TCCA 194和387μmol·L^(-1)组细胞存活率降低(P<0.01),出现细胞核固缩及核碎裂,细胞凋亡率显著增加(P<0.01),细胞被阻滞在G2/M期(P<0.05);TCCA 387μmol·L^(-1)组细胞NO和MDA含量增加(P<0.01),ROS水平升高(P<0.01),GSH和NADPH含量降低(P<0.01),SOD2,GPX4,Nrf2,SLC7A11和DHODH mRNA表达减少(P<0.05,P<0.01);Bax,Fas,DNMT3L和DNMT3A mRNA表达增加(P<0.05,P<0.01)。结论TCCA可降低GC-1细胞存活率,抑制细胞增殖,引起细胞凋亡。其机制可能与其破坏抗氧化系统、增强氧化应激、诱导铁死亡及干扰GC-1细胞甲基化有关。

一种在体标记小鼠精原细胞新生蛋白合成的方法

目的 哺乳动物精子发生是一种由一系列生精细胞组成的连续细胞增殖和分化并最终产生精子的过程。然而,生精细胞的蛋白稳态分析仍缺乏有效手段。本研究的目的是探索一种在体标记并检测生精细胞新生蛋白合成的方法。方法 利用氨基酰tRNAs结构类似物——嘌呤霉素(Puromycin,Puro)以65 mg/kg小鼠体质量的剂量腹腔注射小鼠,1.5 h后,处死小鼠,分离两侧睾丸,其中一侧睾丸用于总蛋白提取,另一侧睾丸用于石蜡切片制备,随后利用Puro特异性抗体分别通过Western blot和免疫荧光检测样品中Puro的含量及定位。结果 Western blot结果显示Puro能够标记总体新生蛋白合成情况;免疫荧光共定位显示Puro在小鼠睾丸中特异性标记的是精原细胞。结论 Puro能够用于小鼠精原细胞新生蛋白质的在体标记,并可通过相应免疫学技术定量分析新生蛋白合成水平。

Ginsenosides stimulated the proliferation of mouse spermatogonia involving activation of protein kinase C

The effect of ginsenosides on proliferation of type A spermatogonia was investigated in 7-day-old mice. Spermatogonia were characterized by c-kit expression and cell proliferation was assessed by immunocytochemical demonstration of proliferating cell nuclear antigen (PCNA). After 72-h culture, Sertoli cells formed a confluent monolayer to which numerous spermatogonial colonies attached. Spermatogonia were positive for c-kit staining and showed high proliferating activity by PCNA expression. Ginsenosides (1.0～10 μg/ml) significantly stimulated proliferation of spermatogonia. Activation of protein kinase C (PKC) elicited proliferation of spermatogonia at 10-8 to 10-7 mol/L and the PKC inhibitor H7 inhibited this effect. Likewise, ginsenosides-stimulated spermatogonial proliferation was suppressed by combined treatment of H7. These results indicate that the proliferating effect of ginsenosides on mouse type A spermatogonia might be mediated by a mechanism involving the PKC signal transduction pathway.

PLZF^posc-KIT^pos-delineated A1-A4-differentiating spermatogonia by subset and stage detection upon Bouin fixation

While hallmarks of rodent spermatogonia stem cell biomarkers' heterogeneity have recently been identified, their stage and subset distributions remain unclear. Furthermore, it is currently difficult to accurately identify subset-specific SSC marker distributions due to the poor nuclear morphological characteristics associated with fixation in 4% paraformaldehyde. In the present study, testicular cross-sections and whole-mount samples were Bouin fixed to optimize nuclear resolution and visualized by immunohistochemistry (IHC) and immunofluorescence (IF). The results identified an expression pattern of PLZFhighc-KITpos in A1 spermatogonia, while A2–A4-differentiating spermatogonia were PLZFlowc-KITpos. Additionally, this procedure was used to examine asymmetrically expressing GFRA1 and PLZF clones, asymmetric Apr and false clones were distinguished based on the presence or absence of TEX14, a molecular maker of intercellular bridges, despite having identical nuclear morphology and intercellular distances that were <25 μm. In conclusion, this optimized Bouin fixation procedure facilitates the accurate identification of spermatogonium subsets based on their molecular profiles and is capable of distinguishing asymmetric and false clones. Therefore, the findings presented herein will facilitate further morphological and functional analysis studies and provide further insight into spermatogonium subtypes.

Mechanistic target of rapamycin kinase(Mtor)is required for spermatogonial proliferation and differentiation in mice

Spermatogonial development is a vital prerequisite for spermatogenesis and male fertility.However,the exact mechanisms underlying the behavior of spermatogonia,including spermatogonial stem cell(SSC)self-renewal and spermatogonial proliferation and differentiation,are not fully understood.Recent studies demonstrated that the mTOR complex 1(mTORC1)signaling pathway plays a crucial role in spermatogonial development,but whether MTOR itself was also involved in any specific process of spermatogonial development remained undetermined.In this study,we specifically deleted Mtor in male germ cells of mice using Stra8-Cre and assessed its effect on the function of spermatogonia.The Mtor knockout(KO)mice exhibited an age-dependent perturbation of testicular development and progressively lost germ cells and fertility with age.These age-related phenotypes were likely caused by a delayed initiation of Mtor deletion driven by Stra8-Cre.Further examination revealed a reduction of differentiating spermatogonia in Mtor KO mice,suggesting that spermatogonial differentiation was inhibited.Spermatogonial proliferation was also impaired in Mtor KO mice,leading to a diminished spermatogonial pool and total germ cell population.Our results show that MTOR plays a pivotal role in male fertility and is required for spermatogonial proliferation and differentiation.

FGFs/FGFRs及其介导信号通路基因的异常表达影响犏牛未分化精原细胞增殖活性

旨在研究FGFs(fibroblast growth factors)/FGFRs(fibroblast growth factor receptors)及其介导的Ras和MAPK信号通路基因在牦牛和犏牛未分化精原细胞的差异表达,以探讨犏牛生精停滞的原因。本研究采集健康的24月龄3头公麦洼牦牛和3头F1代公犏牛的睾丸组织,分为牦牛和犏牛两个样品组,每组3个生物学重复。采用HE染色检测牦牛和犏牛精子发生的差异;采用细胞群体倍增时间、CCK-8和EDU染色检测牦牛和犏牛未分化精原细胞增殖能力的差异;采用荧光定量PCR检测6种FGF家族成员、3种FGFR、FGFs/FGFRs介导的Ras和MAPK信号通路基因在牦牛和犏牛未分化精原细胞中的差异表达。与牦牛相比,犏牛生精小管发育异常,生殖细胞类型单一,未分化精原细胞增殖活性显著低于牦牛(P<0.05)。FGF2、FGF4、FGF5、FGF8、FGF9和FGF21在犏牛睾丸组织及FGFs受体FGFR1、FGFR2和FGFR3在犏牛未分化精原细胞的表达都显著低于牦牛(P<0.01)。FGFs/FGFRs介导Ras信号通路基因中,除HRas和ARaf以外,其余基因(Raf1、BRaf、MEK1和ERK)都是在犏牛未分化精原细胞中以更低的水平表达(P<0.01)。FGFs/FGFRs介导MAPK信号通路基因中,p38、MEKK3、MEKK6和ASK1也是在犏牛未分化精原细胞中低表达(P<0.01)。受Ras通路调控的与细胞增殖相关的基因中,只有SHISA6、ID4在犏牛未分化精原细胞中高表达(P<0.01),其余基因(TAF4B、Etv4、GFRα1和Ret)都是在牦牛未分化精原细胞中表达量高(P<0.01)。受Ras和MAPK通路共同调控的与细胞增殖相关的基因中,ETV5和BCL6B都是在牦牛未分化精原细胞中高表达(P<0.01)。受Ras通路调控的与细胞分化相关的基因中,除PIWIL4外,SOX3、NGN3和Stra8都在牦牛未分化精原细胞中高表达(P<0.01)。因此FGFs/FGFRs及其介导的Ras和MAPK通路基因在犏牛未分化精原细胞中的异常表达,降低了未分化精原细胞增殖活性,导致了犏牛没有足够数量的未分化精原细胞进入分化阶段。这可能是犏牛生精停滞的重要原因之一。

甜味剂乙酰磺胺酸钾的致突变性评价

目的:评价甜味剂乙酰磺胺酸钾的致突变性。方法:细菌回复突变试验(Ames试验)计数各组回复突变菌落数,小鼠精原细胞染色体畸变试验观察各组染色体畸变类型并计算畸变率,小鼠骨髓红细胞微核试验计数各组红细胞微核发生率。结果:Ames试验显示,加或不加S9时,受试物各剂量组、溶剂对照组与空白对照组比较,两次检测各菌株的回复突变数均小于空白对照组2倍;小鼠精原细胞染色体畸变试验显示,受试物各剂量组精原细胞染色体畸变率与对照组比较差异无统计学意义(P>0.05);小鼠骨髓红细胞微核试验显示,受试物各剂量组微核细胞率与对照组比较差异无统计学意义(P>0.05)。结论:乙酰磺胺酸钾未见明显的致突变性。

增塑剂DEHP通过铁死亡途径抑制小鼠GC-1 spg精原细胞生长

目的:探究邻苯二甲酸二(2-乙基己基)酯(di-2-ethylhexyl phthalate,DEHP)损伤小鼠GC-1 spg精原细胞功能的可能机制。方法:采用不同浓度DEHP(0、30、60、90、120μmol/L)处理GC-1 spg细胞,通过CCK8实验、克隆形成实验和Transwell实验检测细胞增殖和迁移能力的变化;化学分光光度比色法检测细胞内铁离子(Fe 3+)和丙二醛的相对含量;蛋白质印迹实验检测细胞内铁死亡相关蛋白胱氨酸/谷氨酸逆转运蛋白(xCT)和谷胱甘肽过氧化物酶4(GPX4)的相对表达;细胞免疫荧光染色技术检测细胞内活性氧水平以及线粒体膜电位(JC-1)的改变。使用铁死亡抑制剂Ferrostatin-1(1μmol/L)与DEHP(90μmol/L)联合培养GC-1 spg细胞24 h,CCK8实验检测细胞的增殖能力。结果:与对照组(0μmol/L)相比,30、60、90、120μmol/L DEHP组细胞的增殖能力、克隆形成能力和迁移能力明显下降;丙二醛、活性氧、Fe 3+(90、120μmol/L DEHP组)含量明显升高;线粒体膜电位(60、90、120μmol/L DEHP组)明显降低;GPX4(60、90、120μmol/L DEHP组)和xCT蛋白表达水平明显降低。DEHP与Ferrostatin-1联合培养后细胞增殖能力较DEHP单独培养明显提高。结论:DEHP能够抑制GC-1 spg细胞的增殖和迁移能力,降低GPX4和xCT蛋白的表达,可能通过铁死亡途径引起细胞死亡。

长链非编码RNA在精子发生调控机制及男性不育中的研究进展

长链非编码(lncRNA)是由RNA聚合酶II转录、长度大于200 nt且不翻译形成蛋白质的RNA分子。在性腺发育和精子发生过程中,lncRNA涉及的表观遗传机制包括DNA甲基化、染色质重塑和组蛋白尾部修饰等,在转录水平或转录后水平起到重要调控作用。包括lncRNA在内的表观组学也被认为是DNA序列的第二维度,可适应环境因素影响在某些细胞中调节特定基因的表达。在本文中,我们基于lncRNA的功能作用机制,综述了有关lncRNA在精子发生及男性不育方向的研究进展,分析了lncRNA作为男性不育生物标志物的潜力,未来可基于lncRNA靶标通过RNA干扰、竞争性结合封闭靶点、lncRNA结构破坏等技术,探究lncRNA在男性不育疾病治疗方面的应用潜力。