Distributions of extracellular matrix and carbonic anhydrase-III during bovine palatine ridge development.

The present study describes histological alterations and immunohistochemical distributions of extracellular matrices (ECMs) and the carbonic anhydrase isozyme-III (CA-III) during the period of bovine palatine ridge formation. Morphogenesis of bovine palatine ridges was preceded by epidermal placodes and the mesenchymal condensation (MC). During the early stages of less than 44 cm crown rump length (CRL), fibronectin (FN) was distributed densely in the MC. Strong reactions against type I collagen (C-1) were detected outer to the FN positive site. In the stages of more than 44 cm CRL, FN and C-1 were distributed diffusely in subepithelial mesenchyme. Laminin (LN) and type IV collagen were distributed in the epithelial and endothelial basement membranes (BMs) in all of the stages examined, except in the stage of 7 cm CRL, where LN was not detected only in the BM just beneath the epidermal placode. CA-III was detected in basal epithelial cells except for palatine ridge rudiments in the stages of more than 21 cm CRL. It is suggested that the expressions of LN and CA-III might play a role in the spatial determination of rudiments of bovine fetal palatine ridges.     

Functional role of type VI collagen during early feather development of the chicken embryo in vitro

The regulatory function of type VI collagen during early feather development in embryonic chickens was investigated at the cellular and organ levels. Immunohistochemical studies of embryonic chicken skin showed that type VI collagen was distributed in spatial‐specific and temporal‐specific manners related to early feather development. To clarify the role of type VI collagen, we studied the feather development in intact, reconstituted and reconstituted gel skin cultures. When ethyl‐3,4‐dihydroxybenzoate (EDHB) was added to the medium of intact skin as an inhibitor of type VI collagen synthesis, the feather buds did not elongate and the number of neural cell adhesion molecule (NCAM)‐positive cells was reduced. However, the magnitudes of both suppressive effects of EDHB were reduced by the addition of liquid type VI collagen. Similar improvement was also observed in the reconstituted skin with liquid type VI collagen and in the reconstituted gel skin with solid type VI collagen at a low concentration. Moreover, type VI collagen promoted feather bud development in the absence of EDHB. However, a high concentration of solid type VI collagen in the reconstituted gel skin arrested the feather bud elongation, and antitype VI collagen antibodies caused feather buds to become longer and smaller in the reconstituted skin. At the cellular level, type VI collagen affected the proliferation, migration and NCAM expression of mesenchymal cells. These results suggest that type VI collagen regulates early feather development by controlling mesenchymal cell behavior.     

鸡皮肤毛囊生长差异基因的生物信息学分析

【目的】 筛选鸡胚胎早期发育期间背部皮肤上皮和间充质中调控毛囊生长的关键基因、生物过程和信号通路,为了解鸡胚胎早期发育期间毛囊生长的分子机制提供参考。【方法】 从GEO数据库中下载基因芯片GSE62882数据集,采用R语言limma包对数据集进行差异分析,分别筛选出胚胎期第7和9天皮肤上皮和间充质差异基因以及皮肤上皮和间充质共同上下调基因,通过STRING在线数据库对差异基因和共同上下调基因进行蛋白互作网络分析,用Cytoscape 3.8.2软件进行可视化,运用R语言中的clusterProfiler程序包对差异基因和共同上下调基因进行GO功能和KEGG通路富集分析。【结果】 皮肤上皮在胚胎期第7和9天共筛选出626个差异基因,获得189条相互作用关系、10个生物过程和4条信号通路;皮肤间充质在胚胎期第7和9天共筛选出690个差异基因,获得326条相互作用关系、10个生物过程和3条信号通路;皮肤上皮和间充质在胚胎期第7和9天共同上调基因26个,共同下调基因48个,共同上下调基因存在34条相互作用关系,主要富集在Wnt信号通路上。【结论】 本研究从鸡胚胎期第7和9天皮肤上皮和间充质中筛选到共同上调基因26个,共同下调基因48个,这些基因主要富集在Wnt信号通路上,为探究上皮和间充质在毛囊生长发育中的作用机制提供理论参考。     

Marek's disease virus-induced skin leukosis in scaleless chickens: tumor development in the absence of feather follicles

Marek's disease virus (MDV) is an oncogenic cell-associated herpesvirus that causes T-cell lymphoma in chickens. Lymphoproliferative neoplasms in Marek's disease (MD) occur in various organs and tissues, including the viscera, peripheral nerves, skin, gonads, and musculatures. MDV is restrictively produced in the feather follicle epithelial (FFE) cells, and it gains access to the external environment via infected cells or as infectious enveloped cell-free virus particles. The goals of the present study were to 1) determine whether the MDV-induced skin lesions are neoplastic in nature or inflammatory reactions to viral infection, 2) determine whether physical presence of feather follicles (FF) is necessary for skin tumor development, and 3) study the role of skin epithelial cells not associated with feathers or FF in the replication and dissemination of infectious virus particles. Scaleless chickens that produce only a few scattered feathers and no sculate scales along the anterior metatarsi were used as a unique model to study the pathogenesis of dermal lesions. Histologic and immunohistochemical analysis revealed that the cutaneous lesions were tumorous as was manifested by massive accumulation of lymphoblasts and extensive activation of meq oncoprotein, the hallmark of MDV oncogenesis, within the skin lesions. Neoplastic cutaneous lesions in the scaleless chickens indicate that feather follicles are not necessary for skin tumor development. Finally, our preliminary data indicate that inoculation with supernatant fluid from homogenized and sonicated skin samples of MDV-infected scaleless chickens induces MD in susceptible birds, suggesting that skin epithelial cells not associated with FF also harbor infectious viral particles.     

A novel DNA virus associated with feather inclusions in psittacine beak and feather disease

The nature of feather inclusions was characterized in 32 psittacine birds (30 cockatoos, one peach-faced lovebird (Agapornis roseicollis), and one red-lored Amazon parrot (Amazona autumnalis autumnalis] with naturally-acquired psittacine beak and feather disease. Intranuclear inclusions within feather epithelial cells and intracytoplasmic inclusions within macrophages in the feather epithelium and pulp cavity contained psittacine beak and feather disease viral antigen when stained by the avidin-biotin complex immunoperoxidase technique. Ultrastructurally, inclusions were observed primarily within macrophages and to a lesser extent within epithelial cell nuclei. Macrophage inclusions appeared as paracrystalline arrays of viral particles. Intranuclear inclusions were less well defined, although scattered viral particles were present. Intracytoplasmic and intranuclear particles in ultrastructural preparations were identified by colloidal gold labeling as psittacine beak and feather disease virus. Feather epithelium was more frequently and severely involved in the disease process than was adjacent follicular epithelium. Plucked feathers with an intact epidermal collar and feather epithelium were preferred to follicular biopsies for histopathologic examination.     

Epithelial cell proliferation and apoptosis in the developing murine palatal rugae

Epithelial cell proliferation and apoptosis during morphogenesis of the murine palatal rugae (PR) were examined histochemically by using anti-bromodeoxyuridine (BrdU) and the terminal deoxynucleotidyl transferase-mediated UTP nick-end-labelling (TUNEL) technique. Formation of the PR rudiment was observed as an epithelial placode in fetuses at 12.5 days post-coitus (dpc). During the PR formation, BrdU-positive cells were detected mainly in the epithelium of the interplacode and interprotruding areas in fetuses administered BrdU maternally at 2 h before killing. TUNEL-positive cells were detected only at the epithelial placode area in 12.5-14.5 dpc. At 16.5-18.5 dpc, the BrdU-positive cells were decreased in number in the epithelial cells at the interprotruding area of the PR. Only a few TUNEL-positive cells were observed in the protruding area of the PR at 16.5 dpc. These results suggest that cell proliferation and apoptosis in the palatal epithelium are involved spatiotemporally in the murine PR morphogenesis.     

Avian polyomavirus infection of a fledgling budgerigar (Melopsittacus undulatus) and differential diagnoses of viral inclusions in psittacine birds--case report and mini-review

A two-week-old budgerigar (Melopsittacus undulatus) of an outdoor aviary died suddenly and was submitted for determination the cause of illness and death. Macroscopically, the sparsely feathered animal was in a poor body condition. Histopathological examination revealed in various mesenchymal and epithelial tissues, numerous up to 15 microm in diameter large intranuclear, amphophilic to basophilic inclusion bodies with a clearing of the centre. Additionally, a feather dysplasia and retention hyperkeratosis of feather follicles was found. Ultrastructurally, viral particles of approximately 35 nm in diameter were detected in the feather follicle epithelium. A PCR for Avian Polyomavirus on fresh skin samples was negative whereas on formalin-fixed kidney samples with a high amount of viral inclusion bodies yielded a positive result. In addition, viral inclusion body diseases, like Avian Poxvirus, Psittacine Beak and Feather disease virus, Avian Adenovirus, Psittacine Herpesvirus and papillomavirus of psittacines are summarized and compared in the present article.     

Bovine papillomavirus DNA can be detected in keratinocytes of equine sarcoid tumors

Bovine papillomavirus (BPV)-1 and -2 is linked to equine sarcoids, a commonly observed skin tumor in horses that is of considerable veterinary importance. Previous studies using in situ hybridization have detected BPV DNA only in fibroblasts and not in keratinocytes of sarcoids. In contrast, normal equine skin latently infected with BPV shows a dysplastic epithelium without dermal changes, similar to lesions induced by other papillomavirus types infecting the epithelium. The first goal of our study was to describe the epidermal and dermal characteristics of several stages in sarcoid development. Next, we explored whether BPV can infect epidermal cells in the horse using real-time PCR on laser-micro-dissected keratinocytes and fibroblasts. We found that latently infected normal skin samples and a subset of early stage sarcoids show dysplastic, koilocyte-like epithelial changes. BPV DNA was detected in keratinocytes in 40% of the samples with these particular epithelial properties, whereas advanced sarcoids only had BPV DNA in the fibroblasts. These data may indicate a novel and intriguing pathway of BPV infection in the horse composed of a first step of keratinocyte infection, followed by migration of viral material towards the dermis resulting in infection of sub-epidermal fibroblasts and their fully transformed phenotype. Additionally, an example of co-existence of a dermal BPV-1 and an epidermal BPV-2 infection in the same lesion is shown, indicating that horses can harbor infection with more than one BPV type at the same time.     

原癌基因c-myc在塔里木马鹿茸不同生长期的表达

为探讨原癌基因c-myc对鹿茸生长的调控作用,选择3头成年塔里木马鹿生长期为30、60d的新鲜鹿茸,剖分成茸皮层、间充质细胞层、成软骨细胞层和软骨细胞层。首先用2种免疫组化的方法进行基因表达定位,然后通过荧光定量PCR技术对不同组织基因表达定量进行分析。结果显示：该基因在茸皮的毛囊内根鞘、毛母质和皮脂腺呈阳性反应,在动脉血管的环形平滑肌、真皮乳头层与表皮基部连接的基底层呈阳性反应。在静脉血管、神经和其他附属器反应均呈阴性。定量分析结果表明c-myc基因在不同生长阶段不同组织层均有表达。茸皮层从生长期30～60d,c-myc表达下调,而在其他3个组织中均上调表达;同一生长期茸皮和软骨层的表达量均高于间充质细胞层和成软骨层（P〈0.05）;不同生长期30、60d组织间基因的表达没有显著的变化。研究结果表明,c-myc基因在鹿茸快速生长期参与了茸皮的增殖与分化;在软骨组织中高表达特别是生长后期,说明原癌基因c-myc对马鹿茸软骨发育及骨形成有着一定调控作用。     

Ultrastructural Studies of Chicken Embryo Chorioallantoic Membrane during Incubation

Structural changes taking place in the chorioallantoic membrane (CAM) of embryonated hen's eggs during incubation were followed up by histological, histochemical and electron microscopic methods. The allantoic sac surrounds the amnionic sac and also the yolk sac by the 7th to 11th day, respectively, and forms together with the chorion the CAM. The mesenchymal layer placing between the chorion of ectodermal and the allantoic layer of entodermal origin develops from the somatic and splanchnic-pleure of the parietal mesoderm. The CAM is composed of three different layers, i.e. chorionic epithelium, mesenchyme and allantoic epithelium. The chorion comprises 2 layers of cubical epithelial cells. In between the 2 layers capillaries and directly under the shell membrane vascular sinuses can be found. Blood circulating in the sinuses is separated from the air in the pores of the shell membrane by the adacent epithelial cell-projections of 0,2 μm thickness, the basal membrane (0.1 μm) and the sinus endothelial layer of 0.2 μm thickness. The mesenchymal cells are of star-like form. The allantioc epithelium is built of one layer of fusiform cells with oval-shaped or rod-like nuclei.     

An outbreak of fatal herpesvirus infection in domestic rabbits in Alaska

A herpesvirus infection affecting mini Rex and crossbred meat rabbits was identified in a rabbitry in Alaska. Illness affected over half of the 55 rabbits on the premises, and 16 rabbits died or were euthanatized because of illness. Disease affected all ages from adults to nursing young and occurred over an approximately 2-month period. Clinical signs included conjunctivitis and periocular swelling, ulcerative dermatitis, progressive weakness, anorexia, respiratory distress, and abortion. Hemorrhagic dermatitis and panniculitis were associated with epidermal microvesicular degeneration, dermal and subcutaneous vascular necrosis, and thrombosis. Eosinophilic intranuclear inclusions consistent with herpesvirus were found within the epidermis and superficial follicular epithelium and within mesenchymal cells within the dermis and subcutis. Syncytial cells containing viral inclusions occurred within the epidermal and superficial follicular epithelium. Other findings were hemorrhagic necrosis of the myocardium with rare intranuclear inclusions within stromal cells, multifocal pulmonary hemorrhage, hemorrhage with sinus erythrophagocytosis in lymph nodes, and massive necrosis and fibrin deposition within red pulp of the spleen. A virus isolated from the skin produced syncytia, intranuclear inclusions, and cell lysis typical of herpesvirus in rabbit kidney cells in vitro. The viral isolate was characterized ultrastructurally as an enveloped virus with icosahedral nucleocapsids 100 nm diameter, consistent with a herpesvirus.     

原癌基因c-fos在塔里木马鹿茸组织中表达特性的研究

为探讨原癌基因c-fos对鹿茸生长的调控作用,采用3头成年塔里木马鹿Cervus elaphus生长期为30、60d的新鲜鹿茸,剖分成茸皮层、间充质细胞层、成软骨细胞层和软骨细胞层。首先用2种免疫组化的方法进行基因表达定位,然后通过荧光定量PCR技术对不同组织基因的表达进行定量分析。免疫组化分析结果表明,该基因在茸皮的毛囊内根鞘和毛母质及皮脂腺、动脉血管的环形平滑肌处呈阳性反应;真皮乳头层与表皮基部连接的基底层呈阳性反应。在静脉血管、神经和其他附属器反应均未观察到阳性细胞。在间充质细胞层、成软骨层和软骨层2种方法均没有观察到c-fos的阳性表达细胞。定量分析发现,c-fos基因在不同生长阶段不同组织层均有表达,且在茸皮的表达量显著的高于间充质细胞层,成软骨层和软骨层(P<0.05)。在同一生长期间充质细胞层、成软骨层和软骨层c-fos的表达量很低;生长30与60d比较,c-fos在间充质细胞层和成软骨层变化不大,在茸皮层和软骨层表现为下调表达。本研究表明c-fos基因在鹿茸快速生长期参与了茸皮干细胞的增殖与分化,并对成骨细胞的分化起着调控作用。     

Air‐liquid interface cell culture: From airway epithelium to the female reproductive tract

The air‐liquid interface (ALI) approach is primarily used to mimic respiratory tract epithelia in vitro. It is also known to support excellent differentiation of 3D multilayered skin models. To establish an ALI culture, epithelial cells are seeded into compartmentalized culture systems on porous filter supports or gel substrata. After an initial propagation period, the culture medium is removed from the apical side of the epithelium, exposing the cells to the surrounding air. Therefore, nutritive supply to the cells is warranted only by the basolateral cell pole. Under these conditions, the epithelial cells differentiate and regain full baso‐apical polarity. Some types of epithelia even generate in vivo‐like apical fluid or mucus. Interestingly, the ALI culture approach has also been shown to support morphological and functional differentiation of epithelial cells that are not normally exposed to ambient air in vivo. This review aims at giving a brief overview on the characteristics of ALI cultures in general and ALI models of female reproductive tract epithelia in particular. We discuss the applicability of ALI models for the investigation of the early embryonic microenvironment and for its implications in assisted reproductive technologies.     

Temporal localization of immunoreactive transforming growth factor beta1 in normal equine skin and in full-thickness dermal wounds

OBJECTIVE: To describe the localization of immunoreactive transforming growth factor (TGF)-beta1 in both normal skin and full-thickness dermal wounds of the limb and the thorax of the horse. STUDY DESIGN: Six full-thickness excisional wounds were created on the lateral aspect of one metacarpal region and on the midthoracic area of each horse. Sequentially collected tissue specimens from wound margins were assessed for TGF-beta1 expression by immunohistochemistry. ANIMALS: Four horses (2 to 4 years of age). METHODS: A neutralizing monoclonal anti-human TGF-beta1 antibody was used to detect the spatial expression of TGF-beta1 protein by immunohistochemical localization in biopsies obtained before wounding and at 12 and 24 hours, and 5, 10, and 14 days. RESULTS: No differences in localization of immunoreactive TGF-beta1 were detected between limb and thorax, for either intact skin or wounds. Unwounded epidermis stained moderately for TGF-beta1 protein throughout all layers, whereas the dermis was relatively devoid of immunoreactivity. During the acute stage of repair, migrating epithelium lost its stain, whereas cells of epidermal appendages remained strongly immunoreactive. The epithelium recovered its TGF-beta1 immunoreactivity during wound remodeling, although cells of the stratum corneum remained negative. Macrophages of the inflammatory exudate had positive cytoplasmic staining that diminished with time. Immunoreactivity of granulation tissue fibroblasts was evident early on and increased throughout the repair process. CONCLUSIONS: TGF-beta1 is constitutively expressed in normal, unwounded equine epithelium. Its expression is upregulated within the skin on injury and is associated with the cells involved in wound repair. CLINICAL RELEVANCE: A more precise understanding of the temporal and spatial expression of TGF-beta1 during wound repair in horses should provide the groundwork for possible future manipulations of both normal and aberrant tissue repair.     

Dome epithelial M cells dissociated from rabbit gut-associated lymphoid tissues

Dome and dome epithelial cells were selectively dissociated from gut-associated lymphoid tissues of rabbits. Sequential tissue washes in dithiothreitol, EDTA, and collagenase removed the dome epithelium, without disrupting the follicles or villi, and provided a cell suspension containing 74 +/- 6% lymphocytes, 9 +/- 4% columnar epithelial cells, 10 +/- 7% tangible-body macrophages, and 4 +/- 2% M cells (follicle-associated epithelial cells). The last mentioned cells were characterized by transmission electron microscopy as large (20 to 55 microns diameter) cuboidal, round, or oval cells with eccentric nuclei and thin membranous processes surrounding empty vacuoles. The M cells were occasionally joined together by tight junctions. Histochemical and immunocytochemical analyses of M cells with the light microscope showed that they were devoid of immunoglobulins and negative for T-cell antigen and secretory component and had no detectable alkaline phosphatase or endogenous peroxidase activity. The M cells had few vacuoles with faint acid phosphatase activity; nonspecific neutral esterase was abundant. Possible uses for dome and dome epithelial cells are discussed.     

Morphological Studies on the Development of the Bronchial Epithelium of the Fetal Camel Lung

Light microscopic observations revealed that in camel foetuses of 25 mm crown‐to‐rump length (CRL) the primordial tubular system of the prospective lung was formed of several tubules lined by undifferentiated columnar epithelium. Intra‐epithelial neuroendocrine cells were the first elements to be differentiated in the lining epithelium of the primordial tubular system of the prospective lung as early as 25 mm CRL. On reaching 50–67 mm CRL, the primordial tubular system started to differentiate into two systems of primordial tubules, the prospective bronchial or light tubules and the future respiratory or dark tubules. The lining epithelium of the prospective bronchial tubules revealed a clear evidence of ciliogenesis as early as 80 mm CRL. From 800 mm CRL onwards, the bronchial epithelium demonstrated ciliated and non‐ciliated secretory cells. The non‐ciliated secretory cells of the bronchial epithelium of fetal camel lung showed moderate reaction to AB/PAS technique, for the first time, in fetuses reaching 600 mm CRL.     

Acantholytic folliculitis and epidermitis associated with Staphylococcus hyicus in a line of white Leghorn laying chickens

Several mature Leghorn-type hens with the same genetic background experienced skin and feather problems in a breeder flock. There was almost-total feather loss on the head and neck, as well as thickened, scaly skin, and follicular ostia were plugged with keratin debris. Other individuals exhibited prominent subcutaneous nodules multifocally on the head. Histologic examination of the skin revealed a severe hyperplasia of follicular epithelium with hyperkeratosis and cystic dilation. Numerous clefts and vesicles were detected along the epidermis and follicular epithelium, some containing acantholytic keratinocytes. A mild heterophilic inflammation was associated with these lesions, and few gram-positive cocci were present in the keratin plugs. Bacterial culture of the skin yielded a variable amount of Staphylococcus hyicus. Immunochemistry looking for chicken IgY revealed no intercellular staining in the epidermis or follicular epithelium. All these findings supported a diagnosis of Staphylococcus-associated acantholytic epidermitis and folliculitis. This case suggests that S. hyicus could be a significant pathogen in poultry production. The close genetic relationship among affected individuals could indicate a hereditary predisposition in this line of White Leghorn laying chickens.     

Histology,histochemistry and ultrastructure of the nasopharyngeal tonsil of the buffalo (Bubalus bubalis)

The light microscopic appearance and ultrastructure of the nasopharyngeal tonsil (tonsilla pharyngea), collected from 12 adult buffaloes of local mixed breed, were explored for the distribution of different types of epithelia, lymphoid tissue and high endothelial venules. The tonsillar mucosa was lined by pseudostratified columnar ciliated epithelium having goblet cells. The respiratory epithelium associated with the underlying lymphoid tissue formed the lymphoepithelium. The epithelium was further modified into follicle‐associated epithelium (FAE) characterized by reduced epithelial height, presence of a few dome‐shaped cuboidal cells equivalent of the M‐cells and absence of goblet and ciliated cells. The lymphoid tissue was distributed in the form of isolated lymphoid cells, diffuse lymphoid tissue and lymphoid follicles, mainly distributed within the propria‐submucosa along with the sero‐mucous glandular tissue. The goblet cells of the respiratory epithelium and the acinar cells contained different mucopolysaccharides. Scanning electron microscopy of the surface mucosa demonstrated a dense mat of cilia, island‐like arrangement of microvillus cells, M‐cells and a few brush‐like cells. The transmission electron microscopy revealed the different cell organelles of the respiratory epithelium and the FAE. Lymphocyte migration via the high endothelial venules in the propria‐submucosa was also observed.     

鸡小肠上皮细胞的分离培养与鉴定

选择组织块法分离培养鸡小肠上皮细胞(intestinal epithelial cells,IEC),采用机械刮除法和相差消化－相差贴壁法纯化细胞,0.05%的Trypsin-EDTA对获得的IEC进行消化传代,免疫细胞化学法鉴定IEC。结果表明,组织块培养法可分离出活性较强的IEC,并获得纯化的上皮细胞;形态学和免疫细胞化学法检测显示获得的细胞表面抗原呈阳性,鉴定为IEC;纯化的IEC可在体外稳定传代。