Spermatogonial stem cells (SSCs), a class of primitive germ cells located on the basement of the seminiferous tubules of the testes, are the only kind of adult stem cells that can pass their genetic material to offspring and are also capable of proliferation and differentiation, ensuring the efficiency of passing transgenes from parents to subsequent generations. In this research, to understand the growth characteristics of buffalo SSCs in vitro, methods for their isolation, enrichment, culture and preliminary identification were established. Testes from 3-to 6-month-old buffalos were digested with two-step enzymatic treatment to obtain isolated single cells and then enriched with a differential plating method. Isolated SSCs were cultured on STO feeder cells with SSCs culture medium (SSCM), which is serum-free. SSCs began to proliferate on the second day and quickly formed grape-like clusters that were consistent with the morphological features of SSCs. These cells were identified as positive by immunofluorescence staining. This study successfully isolated, enriched and identified buffalo SSCs and established an effective platform to explore the mechanisms of proliferation and differentiation of buffalo SSCs.

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FGF2可提高SSCs在体外培养时的自我更新和增殖能力.为此,本研究探索了水牛支持细胞的分离纯化方法,对比了幼年和成年水牛支持细胞FGF2的表达差异,并构建了支持细胞FGF2过表达细胞系.结果表明,幼年水牛支持细胞作为饲养层更有利于维持SSCs的增殖.实时荧光定量PCR显示FGF2在过表达细胞系中的水平显著高于幼年水牛支持细胞对照组的水平.与幼年水牛支持细胞作为饲养层共培养的SSCs相比,FGF2过表达支持细胞系作为饲养层共培养SSCs显著提高PLZF(P＜0.05)、OCT4(P＜0.05)和GFRα1(P＜0.05)的表达水平,并且明显改善了SSCs的体外培养性能.本研究为优化水牛SSCs体外培养系统提供理论和实践基础.

Currently, the systems for culturing buffalo spermatogonial stem cells (SSCs) in vitro are varied, and their effects are still inconclusive. In this study, we compared the effects of culture systems with undefined (foetal bovine serum) and defined (KnockOut Serum Replacement) materials on the in vitro culture of buffalo SSC-like cells. Significantly more DDX4- and UCHL1-positive cells (cultured for 2 days at passage 2) were observed in the defined materials culture system than in the undefined materials system (p < 0.01), and these cells were maintained for a longer period than those in the culture system with undefined materials (10 days vs. 6 days). Furthermore, NANOS2 (p < 0.05), DDX4 (p < 0.01) and UCHL1 (p < 0.05) were expressed at significantly higher levels in the culture system with defined materials than in that with undefined materials. Induction with retinoic acid was used to verify that the cultured cells maintained SSC characteristics, revealing an SCP3⁺ subset in the cells cultured in the defined materials system. The expression levels of Stra8 (p < 0.05) and Rec8 (p < 0.01) were significantly increased, and the expression levels of ZBTB16 (p < 0.01) and DDX4 (p < 0.05) were significantly decreased. These findings provided a clearer research platform for exploring the mechanism of buffalo SSCs in vitro.

In this study, we investigated the localization, morphological features and cellular interactions of telocytes in the rat testicular interstitium. Transmission electron microscopy (TEM) and immunohistochemical and immunofluorescence analyses of the rat testicular interstitium showed a distinct layer of telocytes surround the seminiferous tubules along with inner layer of peritubular myoid cells. The majority of the telocytes were made up of a small cell body and moniliform prolongations that contained mitochondria and secretory vesicles. Some other telocytes were observed possessing large cell bodies. Within the testicular interstitium, the telocytes formed a network connecting peritubular myoid cells, Leydig cells as well as blood vessels. Immunohistochemical and double immunofluorescence analyses showed that rat testicular telocytes express CD34 and PDGFRα, but are negative for vimentin and α-SMA. Our findings demonstrate the presence of telocytes in the rat testicular interstitium. These cells interact with peritubular myoid cells, seminiferous tubules, Leydig cells and blood vessels via long telopode extensions, which suggests their vital role in the intercellular communication between different cell types within the rat testis.

In this study, we investigated the neural changes and their relationships with interstitial cells (ICs) in the rumen of pre-weaning goats by transmission electron microscopy, western blot and immunofluorescence (antibody: general neuronal marker-Protein Gene Product (PGP9.5)/IC marker-vimentin).The immunofluorescence results showed that PGP9.5-positive reaction was widely distributed in neuronal soma (NS) and nerve fibre (NF).The NSs were observed in the ganglia of the myenteric plexus (MP) but not in the submucosal plexus.The mean optical density (MOD) of the whole of PGP9.5-positive nerves and the protein expression level of PGP.5 in the rumen wall both decreased significantly with age.However an obvious increase MOD of PGP.5-positive NFs within the rumen epithelium were observed.In the MP, the nerves and ICs were interwoven to form two complex networks that gradually tightened with age.Furthermore, NSs and nerve trunks were surrounded by a ring-boundary layer consisting of several ICs that became physically closer with aging.Moreover, ICs were located nearby NFs within the ML, forming connections between ICs, smooth muscle cells and axons.This study describes the pattern of neural distribution and its association with ICs in the developing rumen which shed light on the postpartum development of ruminants.

Exosomes are extracellular vesicles with a size of 40-150 nm that are released from a multitude of cell types and are present in biological fluids, which are particularly rich in membrane proteins. These vesicles are present in the bile, where they function as a special regulator of the digestive system; however, their source and characteristics in normal gallbladders have never been discovered. Bile, liver, and gallbladder were obtained from healthy turtles after starvation treatment. Biliary exosomes were extracted and their morphology, particle sizes, and specific proteins were characterized by transmission electron microscope (TEM), nanoparticle tracking analysis (NTA), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) staining, and Western blotting. Furthermore, immunohistochemistry and TEM were used to investigate the distribution of exosomes in both liver and gallbladder. Biliary exosomes had a round or oval shape with apparent bilayer membranes. Biliary exosomes were uniform in size, with a range from 40 to 180 nm in diameter. Immunohistochemistry showed that the CD63 exosome marker was positive and primarily distributed in the hepatocyte junction, while the free surface of gallbladder tested negative. In addition, exosomes were present in bile but absent on the apical free surface of gallbladder. This study provides direct evidences that biliary exosomes are secreted by hepatocytes into bile canaliculus and flow with bile into the gallbladder. The source and the isolated protocol of biliary exosomes may provide technical support and a theoretical basis for the exploration of potential antiviral or anti-inflammatory properties of biliary exosomes.

Telocytes (TCs) have been identified as a distinct type of interstitial cells, but have not yet been reported in the gastrointestinal tract (GIT) of ruminants. In this study, we used transmission electron microscopy (TEM) and double-labelling immunofluorescence (IF) (antibodies: CD34, vimentin and PGP9.5) to seek TCs and investigate their potential functions in the muscle layers of the goat rumen. TCs were distributed widely in the myenteric plexus (TC-MYs) between the circular and longitudinal muscle layers, within circular muscle layers (TC-CMs) as well as in longitudinal muscle layers (TC-LMs). Ultrastructurally, TCs displayed small cell bodies with several long prolongations—telopodes—harboring alternate thin segments (podomers) and dilated segments (podoms). The podoms contained mitochondria, rough endoplasmic reticulum, and caveolae. Telopodes frequently established close physical interactions with near telopodes, collagen fibers (CFs), nerve fibers (NFs), smooth muscle cells (SMCs), nerve tracts, and smooth muscle bundles, as well as with blood vessels (BVs). Furthermore, both homo- and heterotypic connections were observed. In addition, telopodes were capable of releasing extracellular vesicles (EVs). IF analyses proved that TCs were reliably labeled as CD34+/vimentin+ cells, displaying spindle- or triangle-shaped bodies with long prolongations, consistent with TEM results. Specifically, podoms were visible as obvious bright spots. These positive cells covered entire muscular layers, surrounding ganglions, intermuscular BVs as well as entire smooth muscle bundles, forming a network. TC-MYs were distributed as clusters in the external ganglion, encompassing the entire ganglion and spreading to the muscle layers where TC-CMs and TC-LMs seemingly surround whole smooth muscle bundles. TC-MYs were also scattered within the interior of the ganglion, surrounding each ganglionic neuron, following the glial cells layer. We speculate that TCs support the muscle layer structure of the goat rumen and facilitate intercellular signaling directly or indirectly via the TC network.

The objective of this study was to investigate the effects of different growth factors on the proliferation of Bama mini-pig spermatogonial stem cells (SSCs) in vitro. The growth factors glial cell line-derived neurotrophic factor (GDNF), leukaemia inhibitory factor (LIF), GDNF family receptor alpha-1 (GFRα1) and basic fibroblast growth factor (bFGF) were investigated. The SSCs were seeded on SIM mouse embryo-derived thioguanine- and ouabain-resistant (STO) feeder layers. Cultivation of the cells were subjected to a factorial design of the growth factors GDNF + bFGF, GDNF + bFGF + GFRα1, LIF + bFGF and LIF + bFGF + GFRα1. The SSCs could propagate for 25 passages in the medium adding GDNF + bFGF + GFRα1, 22 passages in the medium adding GDNF + bFGF, 6 passages in the medium adding LIF + bFGF, or LIF + bFGF + GFRα1. qRT-PCR analysis showed that the highest mRNA expression levels of NANOG, POU5F, DDX4, GFRα1 and UCHL1 were detected in the group adding GDNF + bFGF + GFRα1. The SSCs from the group adding GDNF + bFGF + GFRα1 also showed UCHL1-, DBA- and CDH1-positive staining. Moreover, Stra8 and Scp3 expression, and haploid peak were detected after induction of the SSCs from the group adding GDNF + bFGF + GFRα1. In conclusion, pig SSCs could be maintained for long term in the presence of GDNF, bFGF, and GFRα1.

Flow cytometry and Laser Tweezers Raman spectroscopy have been used to investigate Nili-Ravi buffalo (Bubalus bubalis) sperm from different samples (fresh, stained, sorted and frozen-thawed) of the flow-sorting process to optimize sperm sex sorting procedures. During the sorting and freezing-thawing processes, the two detection methods both indicated there were differences in mitochondrial activity and membrane integrity. Moreover, a dispersive-type NIR (Near Infrared Reflection) use of the Raman system resulted in the ability to detect a variety of sperm components, including relative DNA, lipid, carbohydrates and protein contents. The use of the Raman system allowed for PCA (principal components analysis) and DFA (discriminant function analysis) of fresh, stained, sorted and frozen-thawed sperm. The methodology, therefore, allows for distinguishing sperm from different samples (fresh, stained, sorted and frozen-thawed), and demonstrated the great discriminative power of ANN (artificial neural network) classification models for the differentiating sperm from different phases of the flow-sorting process. In conclusion, the damage induced by sperm sorting and freezing-thawing procedures can be quantified, and in the present research it is demonstrated that Raman spectroscopy is a valuable technology for assessing sperm quality.

精原干细胞的鉴定对于精原干细胞的体外研究非常重要.本研究证明1月龄巴马小型猪睾丸没有启动精子的发育,而2月龄的巴马小型猪已经启动了精子发育,在其精细小管中发现了精子细胞和精子.免疫荧光染色的结果证明1月龄巴马小型猪精原干细胞表达UCHL1,可以与植物凝集素DBA结合,个别的精原干细胞表达CDH1,但不表达C-KIT.2月龄巴马小型猪精原干细胞只表达UCHL1,不表达CDH1和C-KIT,也不能与DBA结合.这些生物标志物的发现为体外培养的精原干细胞的鉴定奠定了基础.

精原干细胞(spermatogonial stem cells,SSCs)指位于曲精细管基膜上的一类原始精原细胞,近年来因其在生产转基因动物方面有广阔的应用前景,受到了极大的关注.在胚胎发育前期,一小部分细胞分化形成原始生殖细胞(primordial germ cells,PGCs),并迁移至生殖嵴,PGCs随后增殖分化形成生殖母细胞并迁移至睾丸基底膜,随着雄性动物出生,生殖母细胞迁移至细精管并转化成SSCs.本文概述了近年来SSCs的研究进展,主要包括SSCs的分离、鉴定、体外培养体系以及SSCs诱导精子.此外,本文重点阐述了SSCs的研究前景.