Immunohistochemical properties of embryonic telocytes in a myogenic microenvironment.

Telocytes are a unique interstitial cell type that functions in adulthood and embryogenesis. They have characteristic immunohistochemical phenotypes while acquiring different immunohistochemical properties related to the organ microenvironment. The present study aims to investigate the immunohistochemical features of embryonic telocytes during myogenesis and describe their morphology using light microscopy and TEM. Telocytes represent a major cellular constituent in the interstitial elements. They had distinguished telopodes and podoms and formed a 3D interstitial network in the developing muscles. They formed heterocellular contact with myoblasts and nascent myotubes. Telocytes also had distinctive secretory activity. Telocytes identified by CD34. They also express CD68 and MMP-9 to facilitate the development of new tissues. Expression of CD21 by telocytes may reveal their function in immune defense. They also express VEGF, which regulates angiogenesis. In conclusion, the distribution and immunological properties of telocytes in the myogenic tissue indicate that telocytes provide biological and structural support in the development of the myogenic tissue architecture and organization.

A transmission electron microscopy investigation suggests that telocytes, skeletal muscles, myoblasts, and stem cells in common carp (Cyprinus carpio) respond to salinity challenges.

BACKGROUND: Telocytes are modified interstitial cells that communicate with other types of cells, including stem cells. Stemness properties render them more susceptible to environmental conditions. The current morphological investigation examined the reactions of telocytes to salt stress in relation to stem cells and myoblasts. The common carp are subjected to salinity levels of 0.2, 6, and 10 ppt. The gill samples were preserved and prepared for TEM. RESULTS: The present study observed that telocytes undergo morphological change and exhibit enhanced secretory activities in response to changes in salinity. TEM can identify typical telocytes. This research gives evidence for the communication of telocytes with stem cells, myoblasts, and skeletal muscles. Telocytes surround stem cells. Telopodes made planar contact with the cell membrane of the stem cell. Telocytes and their telopodes surrounded the skeletal myoblast. These findings show that telocytes may act as nurse cells for skeletal stem cells and myoblasts, which undergo fibrillogenesis. Not only telocytes undergo morphological alternations, but also skeletal muscles become hypertrophied, which receive telocyte secretory vesicles in intercellular compartments. CONCLUSION: In conclusion, the activation of telocytes is what causes stress adaptation. They might act as important players in intercellular communication between cells. It is also possible that reciprocal interaction occurs between telocytes and other cells to adapt to changing environmental conditions.

Tongue microarchitecture and functional characterization of the lingual papillae in the desert hedgehog (Paraechinus aethiopicus).

The present work attempted to provide a comprehensive description of the morphoanatomical, histological, and ultrastructural characteristics of the tongue in the desert hedgehog (Paraechinus aethiopicus), and to correlate lingual modifications to the feeding lifestyle. Five adult male hedgehogs were utilized in our investigation. The macroscopic observations revealed elongated, with a moderately pointed apex, tongue and the tongue dorsum lacks both lingual prominence and median sulcus. The main subdivisions of the tongue are radix linguae (root), corpus linguae (body), and apex linguae (apex). The tongue dorsum carries two types of mechanical (conical and filiform) and gustatory (fungiform and circumvallate) papillae. The lingual apex is characterized by the existence of a unique encapsulated muscular structure. Additionally, the lingual glands were interposed between the muscular strands and no lingual glands were detected on the lingual apex. The dorsal surface of the lingual apex exhibited the highest level of keratinization as revealed by histochemical staining while the root showed moderate staining. The topography of the tongue was investigated by scanning electron microscopy (SEM). The obtained results are important to provide basic knowledge that can contribute to better understanding of the nourishment, feeding habits and behavior in this species. Furthermore, the addition of the newly investigated species may help us to determine the evolutionary relationships among species.

Characterization of the Small Intestine in the Southern White-breasted Hedgehog (Erinaceus concolor) Using Histological, Histochemical, Immunohistochemical, and Scanning Electron Microscopic Techniques.

The present study was designed to investigate the microscopic features of the small intestine in the southern white-breasted hedgehog (Erinaceus concolor). The histochemical profile of the small intestine was investigated using periodic acid Schiff (PAS), alcian blue (AB, pH 2.5), and aldehyde fuchsin. The expression of SOX9 was also evaluated immunohistochemically, and the detailed morphology of intestinal mucosa was studied by using a scanning electron microscope. The intestinal wall was composed of the tunica mucosa, tunica submucosa, tunica muscularis, and tunica serosa. Plica circulares and muscularis mucosa were present only in the duodenum. The jejunal villi were the tallest and the ileal villi were the shortest. From the duodenum to the ileum, the population density of goblet cells decreased significantly. The goblet cells throughout the small intestine reacted positively with PAS and AB. The expression rate of SOX9 was not statistically different between the three parts of the small intestine (p > 0.05). In conclusion, despite the general characteristics of the small intestine in this species of hedgehog, there were some differences when compared with other mammalian and rodent species. These findings provide a baseline for future detailed research on the digestive system of the hedgehog species and other mammalian species.

Morphological changes in intraepithelial and stromal telocytes in Cyprinus carpio in response to salinity stress.

Telocytes establish connections and communicate with various types of cells and structures. Few experimental studies have been performed on telocytes. In this study, we investigated the effect of salinity stress on telocytes in relation to osmoregulatory, immune, and stem cells. After exposing the common carp to 0.2 (control), 6, 10, or 14 ppt salinity, we extracted and fixed gill samples in glutaraldehyde, processed and embedded the samples in resin, and prepared semi-thin and ultrathin sections. Two types of telocytes were identified: intraepithelial and stromal telocytes. Intraepithelial telocytes were found to form part of the cellular lining of the lymphatic space and shed secretory vesicles into this space. Stromal telocytes were observed to shed their secretory vesicles into the secondary circulatory vessels. Both intraepithelial and stromal telocytes were enlarged and exhibited increased secretory activities as salinity increased. They exerted their effects via direct contact and paracrine signaling. The following changes were observed in samples from fish exposed to high salinity levels: chloride cells underwent hypertrophy, and their mitochondria became cigar-shaped; pavement cells were enlarged, and their micro-ridges became thin and elongated; stromal telocytes established contact with stem cells and skeletal myoblasts; skeletal muscle cells underwent hypertrophy; and macrophages and rodlet cells increased in number. In conclusion, our findings indicate that intraepithelial and stromal telocytes respond to salinity stress by activating cellular signaling and that they play major roles in osmoregulation, immunity, and regeneration.

Histo-morphological Characterization of the Tongue and Oropharyngeal Cavity of the Shining Sunbird (Cinnyris habessinicus).

Sunbirds, as specialized nectarivores, have developed multiple lingual and oropharyngeal peculiarities imposed by this dietary specialization that particularly extract floral nectar. We have described the functional morphology of the tongues and palates of the shining sunbird, Cinnyris habessinicus, using gross anatomical, histological, and scanning electron microscopic methods. The tongue was bifurcated with fringed lamella and extended posteriorly, forming a broad trough at the lingual body and terminating in two fleshy, alae linguae. The lingual apex and body are nonpapillate and nonglandular, and its root had a muscular pad followed by a conspicuous laryngeal mound bordered by three prominent rows of conical papillae. The lingual root had clusters of mucoid glands with rich acidic mucins, and the laryngeal region had complex papillary distribution at the back margins. Both the lingual body and root had well-developed skeletal elements, musculature, and connective tissues. Furthermore, the palate was membranous and made up of four main ridges with a central choanal slit guarded by choanal papillae. Overall, the presented results showed structural and anatomical features that are the results of the nectarivory dietary niche.

Morphology of migrating telocytes and their potential role in stem cell differentiation during cartilage development in catfish (Clarias gariepinus).

Telocytes (TCs) are present in a broad range of species and regulate processes including homeostasis, tissue regeneration and immunosurveillance. This novel study describes the morphological features of migrating TCs and their role during cartilage development within the air-breathing organ in Clarias gariepinus, the African sharptooth catfish. Light microscopy (LM), transmission electron microscopy (TEM), and immunohistochemistry (IHC) were used to examine the TCs. TCs had a cell body and telopodes which formed 3D networks in the cartilage canals and extended their telopodes to become the foremost cellular elements penetrating the cartilage matrix. The TCs were also rich in lysosomes that secreted products to the extracellular matrix (ECM). In addition, TCs formed a homocellular synaptic-like structure that had a synaptic cleft, and the presynaptic portion consisted of a slightly expanded terminal of the telopodes which contained intermediate filaments and secretory vesicles. Gap junctions were also identified between TCs, which also connected to mesenchymal stem cells, differentiating chondrogenic cells, macrophages, apoptotic cells, and endothelial cells. In addition to describing the basic morphology of TCs, the current study also investigated migrating TCs. The TC telopodes acquired an irregular contour when migrating rather than exhibiting an extended profile. Migrating TCs additionally had ill-defined cell bodies, condensed chromatin, thickened telopodes, and podoms which were closely attached to the cell body. The TCs also expressed markers for MMP-9, CD117, CD34 and RhoA. In conclusion, TCs may play multiple roles during development and maturation, including promoting angiogenesis, cell migration, and regulating stem cell differentiation. RESEARCH HIGHLIGHTS: Clarias gariepinus telocytes form 3D networks, extend their telopodes and contain lysosomes. Telocytes form a homocellular synaptic-like structure including clefts and a slightly expanded terminal of the telopodes which contains intermediate filaments and secretory vesicles. Gap junctions form between telocytes, which also connect to mesenchymal stem cells, differentiating chondrogenic cells, macrophages, apoptotic cells, and endothelial cells. Migrating telocytes were discovered which had ill-defined cell bodies, condensed chromatin, thickened telopodes exhibiting irregular contours, and podoms which were closely attached to the cell body.

Morphological and cytochemical characteristics of Varanus niloticus (Squamata, Varanidae) blood cells.

Varanus niloticus is a lizard residing within the Varanidae family. To date no studies detailing its blood morphology and characteristics have been conducted. This study used histologically stained blood and bone marrow samples to visualize the cells and their characteristics. The erythrocytes were nucleated, these nuclei were located in the middle of the elliptical cells. Hemoglobin filled the erythrocyte cytoplasm. Eosinophils were large cells with lobed nuclei and spherical acidophilic granules. Large granulocytes called heterophils were present and characterized by their fusiform/pleomorphic cytoplasmic granules. Small spherical granulocytes, known as basophils, presented with round, deeply stained metachromatic granules that gave the cytoplasm a dusty or cobblestoned appearance which was able to cover the nucleus, which in turn had an unusual shape. Thrombocytes ranged in shape from ellipsoidal to fusiform. They featured an elliptical, centrally located nucleus and a pale cytoplasm, with small vacuoles, and fine acidophilic granulation. The smallest variety of non-granular leukocytes was the lymphocytes. Their cytoplasm was sparse, finely granular, light blue, had tiny cytoplasmic projections, featuring a high nucleus: cytoplasm ratio. Larger and smaller sized populations of lymphocytes were distinguished, with the larger cells similar in size to azurophils. In general, the pleomorphic monocytes were the biggest mononuclear leucocytes, displaying cytoplasmic projections. Their nuclei were ovoid, kidney- or bean-shaped, with vacuolated and granular cytoplasms. Round cells were common among the monocytic azurophils, and they had a granular cytoplasm, and their nuclei were typically eccentric. The present research identifies the cell types and morphologies within the Varanus niloticus. HIGHLIGHTS: H&E, PAS, toluidine blue, methylene blue, and Safranin O stains provided morphological and morphometric descriptions of Varanus niloticus blood cells from blood smears and bone marrow. The Varanus niloticus had nucleated erythrocytes and white blood cells, mostly granulocytes (heterophils, eosinophils, and basophils) and mononuclear cells (azurophils, lymphocytes, and monocytes). Aquatic vertebrate Varanus niloticus had larger erythrocytes than terrestrial counterparts. Blood cell morphological and cytochemical features were similar to other reptilian species, with some species-specific differences, which likely accommodate differing environmental conditions. These results may help clinical researchers track the pathological conditions and support conservation of these wild animals.

Pre-gastric secretory epithelium: A light, scanning and transmission electron microscopic study of an epithelial modification of the esophagus in embryonic quails.

The current study investigated epithelial modification of embryonic quail esophagus using gross examination, light microscopy, transmission and scanning electron microscopy. By semithin sections, the pre-gastric modified region had unfolded mucosa, formed epithelial flabs and pockets, and had reduced muscularis mucosae, thin muscular layer, less glandular tissue, and outer esophageal groove. Conversely, the normal esophageal mucosa was folded, had abundant glandular tissue and prominent muscularis mucosae, with two muscular layers; the outer and the inner. The modified epithelium resembled stratified squamous type that had a high affinity for PAS, methylene blue, and PAP stains. Ultra-structural features of the modified esophageal epithelium resembled stratified squamous epithelium and contained hypertrophic Keratinocytes; dark and light. Hypertrophic keratinocytes had RER organized, few ribosomes, and developed loose bundle of cytokeratin compared with squamous keratinocytes. Hypertrophic Keratinocytes synthesize two types of granules; peripherally located small electron-dense granules and large electron-lucent granules. Hypertrophic keratinocytes had peroxisomes that were identified by the crystalline core of the urate oxidase. In conclusion, epithelia modification may have secretory function. Further studies should be carried out to explain the exact function of this type of modified epithelium.

Anatabine attenuates ovalbumin-induced asthma via oxidative stress and inflammation mitigation and Nrf2/HO-1 signaling upregulation in rats.

AIMS: Asthma affects a large number of people worldwide and is characterized by chronic allergic airway inflammation. Anatabine is a natural alkaloid that is structurally similar to nicotine and found in the Solanaceae family of plants, with anti-inflammatory properties. Consequently, this study aimed to evaluate the potential therapeutic effect of anatabine against asthma. MAIN METHODS: Ovalbumin was used to induce asthma in rats. Two asthmatic groups were treated with low and high doses of anatabine. KEY FINDINGS: Asthmatic animals experienced increased total leukocyte count and inflammatory cytokines in bronchoalveolar lavage fluid (BALF), bronchitis, and bronchopneumonia associated with mast cell infiltration. Additionally, inducible nitric oxide synthase immunostaining was observed, with decreased pulmonary antioxidant capacity and enzymes and decreased Nrf2 and HO-1 gene expression while increased NFκB-P65 expression. Interestingly, asthmatic animals treated with anatabine at both doses showed dose-dependently decreased inflammatory cells and cytokine levels within BALF reduced inflammation in the airways through decreased mast cell infiltration within lung tissues and increased antioxidant enzymes and Nrf2 and Ho-1 expression levels. SIGNIFICANCE: Our results highlight the potential beneficial effect of anatabine against asthma through anti-inflammatory and antioxidant mechanisms. Therefore, anatabine is a promising candidate for pulmonary asthma treatment.

Therapeutic Versus Preventative Use of Ginkgo biloba Extract (EGb 761) against Indomethacin-Induced Gastric Ulcer in Mice.

The main bioactive constituents in the standardized Ginkgo biloba leaf extract (EGb 761) are the terpene lactones and flavonoid glycosides. EGb 761's antioxidant and anti-inflammatory properties have previously been demonstrated. Indomethacin-induced gastric ulcers have a multifactorial etiology and represent a major restriction to its therapeutic utility. The underlying ulcerogenic process involves oxidative and inflammatory biomolecular insults. This study was performed to explore the curative and preventative benefits of EGb 761 in experimentally-induced ulcers. To develop gastric ulcers in mice, indomethacin (40 mg/kg) was administered orally. EGb 761 (200 mg/kg) was given by gavage for 7 days before (preventative) and after (therapeutic) indomethacin administration. The histological alterations and macroscopic mucosal lesions were assessed. In gastric tissue homogenates, malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO), and inflammatory cytokines were measured. The expressions of cyclooxygenase-2 (COX-2), cytokines, and proliferating cell nuclear antigen (PCNA) in the stomach mucosa were also investigated. The ulcer index, histological alterations, gastric oxidants, and inflammatory biomarkers were all significantly increased by indomethacin. In stomach specimens, it increased COX-2 and PCNA expression. EGb 761 treatments, both prophylactic and therapeutic, resulted in significant reductions in ulcer lesions, nitrosative and oxidative damage, and inflammatory markers, along with the lowering of COX-2 and PCNA expressions. Furthermore, in the fight against stomach ulcers, EGb 761 treatment was found to be more efficient than prevention.

Two distinctive types of telocytes in gills of fish: A light, immunohistochemical and ultra-structure study.

Telocytes (TCs) are a vital constituent of interstitial tissue. They contribute to regulating cell function in heterotypic connections via direct contact or paracrine singling. Few studies mentioned intraepithelial TCs; however, they have been identified with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In this study, we investigated the intraepithelial and interstitial TCs using immunohistochemistry (IHC) and TEM. TCs can be identified by their distinctive telopodes (TPs), which consist of podoms and podomere, using TEM and immunohistochemical staining with CD34, CD117, and VEGF antibodies. Intraepithelial TCs established heterocontact with the lamellar capillary and interstitial TCs connected with the blood vessel in lamina propria. Intraepithelial TCs established direct contact with epithelial cells, which formed the lymph space while interstitial TCs connected with the secondary vascular vessels. The study provides evidence for TCs' heterocontact with lamellar blood capillaries, the blood vessels, chloride cells, and immune cells, such as rodlet cells and lymphocytes. In conclusion, TCs have a role in regulating respiratory activities, maintaining osmotic pressure, modulating the immune response, and conducting immunosurveillance. RESEARCH HIGHLIGHTS: We investigated the intraepithelial and interstitial TCs using immunohistochemistry (IHC) and TEM. TCs can be identified by their distinctive telopodes (TPs), which consist of podoms and podomere, using TEM and immunohistochemical staining with CD34, CD117, and VEGF antibodies. Intraepithelial TCs established heterocontact with the lamellar capillary and interstitial TCs connected with the blood vessel in lamina propria.

Lactoferrin improves the immune response and resistance of silver carp, a hematological, light (histochemical and immunohistochemical), fluorescent, and scanning electron microscopic study.

Lactoferrin is a multifunctional protein that has roles in iron metabolism, cell generation and differentiation, and antibacterial, antiviral, and antiparasitic activity. The study aim was to evaluate the effect of dietary lactoferrin powder on the innate immune response and disease resistance of silver carp (Hypophthalmichthys molitrix) infected with Vibrio vulnificus. The study also investigates immune cells in different organs including gills, intestine, spleen, liver, and pancreas using light, scan electron microcopy. Two diet regimes, a basic diet and a 600-mg/kg bovine lactoferrin-supplemented diet were used. The fish were fed for 30 successive days. We included 270 apparently healthy silver carp (H. Molitrix) with an average body weight of 10 ± 2 g/fish. Addition of lactoferrin to the diet led to an increase in the activity of non-specific immune parameters; lymphocytes, and in the monocytes percentage, and in total protein, serum globulin, and albumin, with a corresponding increase in phagocytic activities and indices. The histological analysis revealed increase immune cells such as lymphocytes in intestine, rodlet cells in liver, gills, and pancreas, and the macrophages in liver, pancreas as well as spleen. The lactoferrin-supplemented diet significantly increased survival and disease resistance following V. vulnificus challenge, which seemed to correspond to an enhancement of non-specific immune functions in H. molitrix. RESEARCH HIGHLIGHTS: The study evaluates the effect of dietary lactoferrin powder on the innate immune response and disease resistance of silver carp (Hypophthalmichthys molitrix) infected with Vibrio vulnificus. The study also investigates immune cells in different organs including gills, intestine, spleen, liver, and pancreas using light, scan electron microcopy. Lactoferrin increases the activity of nonspecific immune parameters; lymphocytes, and in the monocytes percentage, and in total protein, serum globulin, and albumin, with a corresponding increase in phagocytic activities and indices. The histological analysis revealed increase immune cells such as lymphocytes in intestine, rodlet cells in liver, gills, and pancreas, and the macrophages in liver, pancreas as well as spleen.

Detection of food fraud of meat products from the different brands by application of histological methods.

In Sohag City, 400 samples were collected from different food markets of different meat products from two companies with high and low prices (e.g., minced meat, kofta sausage, beef burger, and luncheon meat) for determining food fraud. Light, fluorescence, and scanning electron microscopy (SEM) were used to examine the samples. "Special histochemical stains" permit the microscopic examination of different cell types, structures, and/or microorganisms. Histological examination revealed variant tissue types, besides skeletal muscles. Nuchal ligaments, bones, hyaline cartilages, white fibrocartilages, large and medium arteries, cardiac muscles, tendons, and collagenous connective tissues comprised the capsule of a parenchymatous organ. Additionally, a crystal of food additives was recognized using light microscopy and SEM. SEM allows the visualization of bacterial contamination. Using different microscopic anatomy techniques is an efficient methodology for qualitative evaluations of various meat products. No difference in quality was observed between low- and high-priced meat products.

Aloe vera and wound healing: a brief review

Abstract Aloe vera possesses a great therapeutic importance in traditional medicine. It has attracted the attention of modern medical fields due to its wide pharmacological applications. The bioactive substances in Aloe vera proved to have antioxidant, anti-inflammatory, antibacterial, and antiviral properties. Taken into our consideration the long history of clinical applications of Aloe vera in traditional medicine, especially for promoting the healing of cutaneous wounds with rare adverse effects, it provides a cheap alternative to many expensive synthetic drugs. Recent techniques in tissue engineering created novel scaffolds based on Aloe gel extracts for wound healing applications. Nonetheless, further guided researche is required to foster the development of Aloe vera based scaffolds for the benefit of worldwide populations. Here, I systemically summarize the main events following wounding and the mechanism of action of Aloe vera in promoting the healing process. I hope to provide a solid piece of information that might be helpful for designing new research studies into this topic.

Endocrine, Stemness, Proliferative, and Proteolytic Properties of Alarm Cells in Ruby-Red-Fin Shark (Rainbow Shark), Epalzeorhynchos frenatum (Teleostei: Cyprinidae).

The current study investigated the morphological, histochemical, and immunohistochemical characteristics of alarm cells and their precursors in ruby-red-fin shark (rainbow shark), Epalzeorhynchos frenatum (Teleostei: Cyprinidae). Precursor alarm cells were shown to be small, cuboidal, pyramidal, or round in shape, with eosinophilic cytoplasm, resting on the basement membrane of the epidermis. The cells later elongated to become columnar in shape. Subsequently, they enlarged and became large oval-shaped cells. They then underwent shrinkage and vacuolation. The superficial alarm cells were collapsed. Alarm cells were found to have an affinity for different histochemical stains, including bromophenol blue, iron hematoxylin, Sudan black, Mallory triple trichrome, Crossman's trichrome, Safranin O, and Weigert's stains, as well as lipase and alkaline phosphatase. Endocrine properties of the alarm cells were identified by silver staining and synaptophysin immunostaining. Alarm cells exhibited stemness activities and had a strong immunoaffinity for CD117. They had a proteolytic function, as identified by lysosome-specific staining with acridine orange and strong immunoaffinity for matrix metalloproteinase (MMP-9). They also exhibited proliferatively, reflected by immunological staining by proliferating cell nuclear antigen. In conclusion, alarm cells are unique epidermal cells with multiple functions. They play immunological, and endocrine, roles. They also retain stemness and proliferative properties.

Developmental events and cellular changes occurred during esophageal development of quail embryos.

The current study focused on the histogenesis of the esophagus in quail embryos. Formation of the gut tube occurred on the 4th day of incubation. Development of the muscular layers occurred in a sequential manner; the inner circular layer on the 7th day, the outer longitudinal layer on the 8th day and the muscularis mucosae on the 9th day. Glandular development began on the 13th day of incubation. The epithelium was pseudostratified columnar that consisted of mucous cells, dendritic cells, and keratinocyte precursors. Epithelial stratification occurred on the 15th day of incubation. We used Mallory trichrome, Weigert-Van Gieson, and Gomori silver stains to visualize fibrous components. Scanned samples showed formation of endoderm and mesoderm on the 5th day of incubation. A layer of myoblasts developed on the 8th day of incubation. Formation of mucosal folds, which contained glandular openings, occurred on the 14th to 17th days of incubation. On the 5th to 8th days of incubation, CD34 and vascular endothelial growth factor (VEGF) positive-mesodermal cells, and telocytes (TCs) were detected. On the 15th day of incubation, CD34 and VEGF positive-telocytes, and fibroblasts, were identified. The current study described the correlations between functional morphology and evolutionary biology.

Telocytes are major constituents of the angiogenic apparatus.

The current study investigated role of telocytes (TCs) in angiogenesis during embryonic development of quail using immunohistochemistry (IHC), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The angiogenic apparatus consisted of TCs, endothelial cells, and macrophages. TCs were identified morphologically by their telopodes and podoms using TEM and SEM and immunohistochemically using CD34, and vascular endothelial growth factor (VEGF). TCs also expressed CD68. TCs formed a three-dimensional network and established direct contact with blood vessels, sprouting endothelial cells, and active macrophages, while exerting their effect through paracrine signaling. VEGF was also expressed by endothelial cells and macrophages. Matrix metalloproteinase-9 (MMP-9) was expressed by TCs, endothelial cells, and macrophages. In conclusion, the expression of VEGF by TCs, endothelial cells, and macrophages is required for the proliferation and migration of endothelial cells and vascular growth. The expression of MMP-9 by TCs, endothelial cells, and macrophages is essential for the degradation of extracellular matrix (ECM) components during neoangiogenesis. Macrophages may facilitate phagocytosis and elimination of the degraded ECM components.