1
|
Kose F, Orhan I, Alan A, Cabir A, Beyaz F, Duzler A. A new perspective on the corneo-scleral junction with three types of microscopy techniques. Microsc Res Tech 2023; 86:629-635. [PMID: 36929228 DOI: 10.1002/jemt.24314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 03/03/2023] [Indexed: 03/18/2023]
Abstract
The conjunctions of the cornea and sclera in the eyes of donkeys, cattle, dogs, sheep, pigs and rabbits, regardless of gender, were examined in this study. No animals were specifically sacrificed for this investigation. Scanning electron microscopy, light microscopy, and dissecting microscopy were used in this research. In the limbus of all the animals investigated, the cornea and sclera fused in accordance with a pattern. At the corneo-scleral junction, the sclera was situated anteriorly and the cornea posteriorly in the dorsal and ventral sections of the bulbus oculi. In the medial and lateral parts of the eyeball, the cornea and sclera were facing each other and interlaced. Pigmentation and the sulcus scleralis externus could be used to identify the macro-and micro-anatomical boundaries of the limbus. In addition, the cytoplasm of basal epithelial cells shrank, signaling the end of the corneal epithelium and the start of the conjunctival epithelium. The presence of Bowman's membrane in cattle and sheep eyes was definitely determined in histological examinations. Bowman's membrane in these animals came to an end at the limbus, which is where the conjunctival epithelium starts and the corneal epithelium ends. In all areas of the cornea, Bowman's membrane revealed irregular, abrupt thickening and thinning. The corneal epithelium was thick in the vertex and thinner towards the limbus, whereas Descemet's membrane was thin in the center (vertex) and thick in the periphery (near the limbus). In this study, pictures and diagrams were used to illustrate the general anatomical, histological, and morphometric characteristics of the limbus in the species under investigation. The data from our study showed that the limbus region of the bulbus oculi was narrow in the lateral and medial parts and wide in the dorsal and ventral parts. This was confirmed in the studied animals as a general rule. The width value will undoubtedly affect the number of cells covered by the regions. It is conceivable that these cells will play a significant role in the decision of where to perform surgical procedures in order to promote wound healing, giving doctors an advantage. In this circumstances, we think that the limbus should be studied in terms of clinical methods because it has different shapes depending on the species and the position of the bulbus.
Collapse
Affiliation(s)
- Fatma Kose
- Department of Veterinary Anatomy, Institute of Health Sciences, Erciyes University, Kayseri, Turkey
| | - Imdat Orhan
- Erciyes Üniversitesi Teknoloji Geliştirme Bölgesi (TEKNOPARK), Kayseri, Turkey
| | - Aydın Alan
- Faculty of Veterinary Medicine, Department of Anatomy, Erciyes University, Kayseri, Turkey
| | - Ahmet Cabir
- Department of Veterinary Histology and Embryology, Institute of Health Sciences, Erciyes University, Kayseri, Turkey
| | - Feyzullah Beyaz
- Faculty of Veterinary Medicine, Department of Histology and Embryology, Erciyes University, Kayseri, Turkey
| | - Ayhan Duzler
- Faculty of Veterinary Medicine, Department of Anatomy, Erciyes University, Kayseri, Turkey
| |
Collapse
|
2
|
Comparative Histology of the Cornea and Palisades of Vogt in the Different Wild Ruminants (Bovidae, Camelidae, Cervidae, Giraffidae, Tragulidae). Animals (Basel) 2022; 12:ani12223188. [PMID: 36428415 PMCID: PMC9687073 DOI: 10.3390/ani12223188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 11/19/2022] Open
Abstract
In the study, we data concerning the histological and morphometrical examination of the cornea and palisades of Vogt in the different species of ruminants from the families Bovidae, Camelidae, Cervidae, Giraffidae and Tragulidae, coming from the Warsaw Zoological Garden, the Wroclaw Zoological Garden and the Division of Animal Anatomy. The following ruminant species were investigated: common wildebeest, Kirk's dik-dik, Natal red duiker, scimitar oryx, sitatunga, Philippine spotted deer, Père David's deer, moose, reindeer, reticulated giraffe, okapi, Balabac mouse-deer and alpaca. The cornea of ruminant species such as the common wildebeest, Kirk's dik-dik, Natal red duiker, scimitar oryx, reindeer and Balabac mouse-deer consisted of four layers (not found in the Bowman's layer): the anterior corneal epithelium, the proper substance of the cornea, the posterior limiting membrane (Descemet's membrane) and the posterior corneal epithelium (endothelium). The anterior corneal epithelium was composed of a multilayer keratinizing squamous epithelium, which was characterized in the studied ruminants with a variable number of cell layers but also with a different thickness both in the central epithelium part and in the peripheral part. Moreover, the proper substance of cornea was thinnest in Balabac mouse-deer, Kirk's dik-dik, Natal red duiker, scimitar oryx, Philippine spotted deer, alpaca, reindeer and sitatunga and was thickest in the reticulated giraffe. The thickest Descemet's membrane was observed in the Père David's deer. The corneal limbus is characterized by a large number of pigment cell clusters in Kirk's dik-dik, scimitar oryx, moose, Balabac mouse-deer and alpaca. In the common wildebeest, Père David's deer, moose, reticulated giraffe, okapi and alpaca, the palisades of Vogt were marked in the form of a crypt-like structure. The corneal limbus epithelium in the examined ruminants was characterized by a variable number of cell layers but also a variable number of melanocytes located in different layers of this epithelium. The detailed knowledge of the corneal structure of domestic and wild animals can contribute to the even better development of methods for treating eye diseases in veterinary medicine.
Collapse
|
3
|
Popova P, Malalana F, Biddolph S, Ramos T, Parekh M, Chantrey J, Ahmad S. Interspecies comparative morphological evaluation of the corneal epithelial stem cell niche: a pilot observational study. J Vet Sci 2022; 23:e62. [PMID: 35920126 PMCID: PMC9346529 DOI: 10.4142/jvs.22009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/05/2022] [Accepted: 04/15/2022] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The corneal and limbal morphology relevant to corneal epithelial maintenance in ten different species was examined using histological methods. OBJECTIVES The presence of a Bowman's layer, limbal epithelial cell, and superficial stromal morphology was examined in the following species to evaluate the differences in corneal thickness and epithelium: Java sparrows, frogs, macaws, spoonbills, red pandas, penguins, horses, Dobermans, orangutans, and humans. METHODS Corneal sections (4 µm) were obtained from ten ocular globes from three different animal classes: Aves, Amphibia, and Mammalia. All sections were stained with hematoxylin and eosin and periodic acid-Schiff reaction. After microscopy, all stained slides were photographed and analyzed. RESULTS Significant morphological differences in the corneal and limbal epithelia and their underlying stroma between species were observed. The number of corneal epithelial cell layers and the overall corneal epithelial thickness varied significantly among the species. The presence of a Bowman's layer was only observed in primates (orangutans and humans). Presumed supranuclear melanin caps were noted in four species (orangutans, macaws, red pandas, and horses) in the limbal basal epithelial layer (putative site of corneal epithelial stem cells). The melanin granules covered the apex of the cell nucleus. CONCLUSIONS Supranuclear melanin capping has been described as a process within the epidermis to reduce the concentration of ultraviolet-induced DNA photoproducts. Similarly, there may be a relationship between limbal stem cell melanin capping as a protective mechanism against ultra-violet radiation.
Collapse
Affiliation(s)
- Petya Popova
- Department of Eye and Vision Science, University of Liverpool, Liverpool L7 8TX, UK
| | - Fernando Malalana
- Institute of Veterinary Science, University of Liverpool, Liverpool L3 5RF, UK
| | - Simon Biddolph
- National Specialist Ophthalmic Pathology Service, Royal Liverpool University Hospital, Liverpool L7 8XP, UK
| | - Tiago Ramos
- Department of Eye and Vision Science, University of Liverpool, Liverpool L7 8TX, UK
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Mohit Parekh
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Julian Chantrey
- Institute of Veterinary Science, University of Liverpool, Liverpool L3 5RF, UK
| | - Sajjad Ahmad
- Department of Eye and Vision Science, University of Liverpool, Liverpool L7 8TX, UK
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK.
| |
Collapse
|
4
|
Farouk SM, Mahmoud SF, Eldoumani H, Shoghy K, Abdel-Megeid NS, Abdo M. Scanning electron microscopy and morphometric analysis of superficial corneal epithelial cells in dromedary camel (Camelus dromedarius). Microsc Res Tech 2021; 85:1685-1693. [PMID: 34919295 DOI: 10.1002/jemt.24030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/11/2021] [Accepted: 12/01/2021] [Indexed: 12/25/2022]
Abstract
It is likely that superficial corneal epithelial cells (SCECs) of the dromedary camels have a significant role in their survival at arid and semiarid regions. To the best of our knowledge, SCECs of camels' eyes have not been characterized previously using scanning electron microscopy (SEM), combined with morphometric analysis. Therefore, in the current study, we aim to describe the shape, topographical distribution, and density of SCECs associated with morphometric analysis using SEM. Twelve healthy adult camels' corneas were obtained immediately after slaughter. Each cornea has been divided into nine parts: central (C), middle dorsal (MD), middle ventral (MV), middle nasal (MN), middle temporal (MT), peripheral dorsal (PD), peripheral ventral (PV), peripheral nasal (PN), and peripheral temporal (PT). SCECs were distinguished and characterized into light, medium, and dark mosaics. The polygonal cells have been externally covered with microplicae that were more numerous above the light cells. The topographic distribution of light, medium, and dark cells revealed a well-defined concentration of light cells in excess of other cells in all parts as follows: PV (92.5%), PN (78.5%), MN (78%), MT (74.7%), PD (73.8%), PT (70.7%), MV (68.7%), MD (66.3%), and C (19.3%). The PV part recorded the highest density of light cells, while the C portion showed the lowest density for the same cells. We concluded that the light cells extensively predominate in all parts of the camels' cornea except the C part, indicating an adaptive modification to the harsh environment. Additionally, the PV and PN parts represent the permanent and endogenous source as well as a proliferative reserve for SCECs in dromedary camel.
Collapse
Affiliation(s)
- Sameh M Farouk
- Department of Cytology and Histology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt
| | - Samy F Mahmoud
- Department of Biotechnology, College of Science, Taif University, Taif, Saudi Arabia
| | - Haitham Eldoumani
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Khaled Shoghy
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Egypt
| | - Nazema S Abdel-Megeid
- Department of Cytology and Histology, Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Egypt
| | - Mohamed Abdo
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Egypt.,Department of Animal Histology and Anatomy, School of Veterinary Medicine, Badr University in Cairo (BUC), Cairo, Egypt
| |
Collapse
|
5
|
Mutoji KN, Sun M, Elliott G, Moreno IY, Hughes C, Gesteira TF, Coulson-Thomas VJ. Extracellular Matrix Deposition and Remodeling after Corneal Alkali Burn in Mice. Int J Mol Sci 2021; 22:5708. [PMID: 34071909 PMCID: PMC8199272 DOI: 10.3390/ijms22115708] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/13/2022] Open
Abstract
Corneal transparency relies on the precise arrangement and orientation of collagen fibrils, made of mostly Type I and V collagen fibrils and proteoglycans (PGs). PGs are essential for correct collagen fibrillogenesis and maintaining corneal homeostasis. We investigated the spatial and temporal distribution of glycosaminoglycans (GAGs) and PGs after a chemical injury. The chemical composition of chondroitin sulfate (CS)/dermatan sulfate (DS) and heparan sulfate (HS) were characterized in mouse corneas 5 and 14 days after alkali burn (AB), and compared to uninjured corneas. The expression profile and corneal distribution of CS/DSPGs and keratan sulfate (KS) PGs were also analyzed. We found a significant overall increase in CS after AB, with an increase in sulfated forms of CS and a decrease in lesser sulfated forms of CS. Expression of the CSPGs biglycan and versican was increased after AB, while decorin expression was decreased. We also found an increase in KS expression 14 days after AB, with an increase in lumican and mimecan expression, and a decrease in keratocan expression. No significant changes in HS composition were noted after AB. Taken together, our study reveals significant changes in the composition of the extracellular matrix following a corneal chemical injury.
Collapse
Affiliation(s)
- Kazadi N. Mutoji
- College of Optometry, University of Houston, Houston, TX 77204, USA; (K.N.M.); (M.S.); (G.E.); (I.Y.M.); (T.F.G.)
| | - Mingxia Sun
- College of Optometry, University of Houston, Houston, TX 77204, USA; (K.N.M.); (M.S.); (G.E.); (I.Y.M.); (T.F.G.)
| | - Garrett Elliott
- College of Optometry, University of Houston, Houston, TX 77204, USA; (K.N.M.); (M.S.); (G.E.); (I.Y.M.); (T.F.G.)
| | - Isabel Y. Moreno
- College of Optometry, University of Houston, Houston, TX 77204, USA; (K.N.M.); (M.S.); (G.E.); (I.Y.M.); (T.F.G.)
| | - Clare Hughes
- School of Biosciences, Cardiff University, Cardiff CF10 3AT, UK;
| | - Tarsis F. Gesteira
- College of Optometry, University of Houston, Houston, TX 77204, USA; (K.N.M.); (M.S.); (G.E.); (I.Y.M.); (T.F.G.)
- Optimvia, Batavia, OH 45103, USA
| | - Vivien J. Coulson-Thomas
- College of Optometry, University of Houston, Houston, TX 77204, USA; (K.N.M.); (M.S.); (G.E.); (I.Y.M.); (T.F.G.)
| |
Collapse
|
6
|
Ehrlich F, Laggner M, Langbein L, Burger P, Pollreisz A, Tschachler E, Eckhart L. Comparative genomics suggests loss of keratin K24 in three evolutionary lineages of mammals. Sci Rep 2019; 9:10924. [PMID: 31358806 PMCID: PMC6662840 DOI: 10.1038/s41598-019-47422-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/16/2019] [Indexed: 12/18/2022] Open
Abstract
Keratins are the main cytoskeletal proteins of epithelial cells and changes in the expression of keratins have contributed to the evolutionary adaptation of epithelia to different environments. Keratin K24 was proposed to be a differentiation marker of epidermal keratinocytes but the significance of K24 expression in the epidermis versus other tissues has remained elusive. Here, we show by RT-PCR, western blot, and immunofluorescence analyses that K24 is highly expressed in the epithelium of the cornea whereas its expression levels are significantly lower in other stratified epithelia including in the epidermis. To investigate the evolutionary history of K24, we screened the genome sequences of vertebrates for orthologs of the human KRT24 gene. The results of this comparative genomics study suggested that KRT24 originated in a common ancestor of amniotes and that it was lost independently in three clades of mammals, i.e. camels, cetaceans, and a subclade of pinnipeds comprising eared seals and the walrus. Together, the results of this study identify K24 as component of the cytoskeleton in the human corneal epithelium and reveal previously unknown differences of keratin gene content among mammalian species.
Collapse
Affiliation(s)
- Florian Ehrlich
- Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Maria Laggner
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
- Aposcience AG, Vienna, Austria
| | - Lutz Langbein
- German Cancer Research Center, Department of Genetics of Skin Carcinogenesis, Heidelberg, Germany
| | - Pamela Burger
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Andreas Pollreisz
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Erwin Tschachler
- Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Leopold Eckhart
- Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria.
| |
Collapse
|
7
|
Kammergruber E, Rahn C, Nell B, Gabner S, Egerbacher M. Morphological and immunohistochemical characteristics of the equine corneal epithelium. Vet Ophthalmol 2019; 22:778-790. [PMID: 30767359 PMCID: PMC6900071 DOI: 10.1111/vop.12651] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/18/2019] [Accepted: 01/21/2019] [Indexed: 12/13/2022]
Abstract
Objective The morphology of the corneal epithelium in two age groups of horses is described. Distribution patterns of proliferation‐, differentiation‐, stem cell‐associated markers and cell junction proteins were assessed. Methods Corneal samples from 12 horses (six foals and six adult horses) were analyzed after H&E staining and immunohistochemistry using the following antibodies: E‐cadherin, β‐catenin, Connexin 43 (Cx43), tight junction protein 1 (TJP1), cytokeratin (CK) 14, CK 19, CK 3, CK 10, vimentin, Ki67, p63, nerve growth factor (NGF), ABCG2, and epithelial growth factor receptor. Semiquantitative analysis of crypt, limbal, peripheral, and central zone was performed. Semithin and ultrathin sections were used for ultrastructural evaluation of the epithelium. Results The height of the epithelium varied between age groups and crypts were consistently present. In the peripheral and central epithelium, three types of basal cells resembling a pseudostratified epithelium were characterized. Potential stem cell markers (CK 14, p63, NGF, and ABCG2) were present in all zones with decreasing frequency toward the center. Cornea‐specific differentiation marker CK 3 was not expressed in the most basal cell layer of the limbal epithelium. E‐cadherin, β‐catenin, and Cx43 revealed a similar apico‐lateral signal pattern throughout the entire epithelium; only TJP1 was additionally seen at the basal surface. Conclusions This study presents a systematic semiquantitative evaluation of the equine corneal epithelium, showing the presence of crypts as potential stem cell niche with CK 14, p63, NGF, and ABCG2 as relevant markers for cells with regenerative capacity. The pseudostratified arrangement of the basal layer was a unique finding.
Collapse
Affiliation(s)
- Eva Kammergruber
- Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Carolin Rahn
- Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Barbara Nell
- Department of Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria
| | - Simone Gabner
- Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Monika Egerbacher
- Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| |
Collapse
|
8
|
Klećkowska-Nawrot JE, Goździewska-Harłajczuk K, Darska M, Barszcz K, Janeczek M. Microstructure of the eye tunics, eyelids and ocular glands of the Sulawesi bear cuscus (Ailurops ursinusTemminck, 1824) (Phalangeridae: Marsupialia) based on anatomical, histological and histochemical studies. ACTA ZOOL-STOCKHOLM 2018. [DOI: 10.1111/azo.12251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Joanna E. Klećkowska-Nawrot
- Department of Biostructure and Animal Physiology; Faculty of Veterinary Medicine; Wroclaw University of Environmental and Life Sciences; Wroclaw Poland
| | - Karolina Goździewska-Harłajczuk
- Department of Biostructure and Animal Physiology; Faculty of Veterinary Medicine; Wroclaw University of Environmental and Life Sciences; Wroclaw Poland
| | - Marta Darska
- Faculty of Biology and Animal Science; Wroclaw University of Environmental and Life Sciences; Wroclaw Poland
| | - Karolina Barszcz
- Department of Morphological Sciences; Faculty of Veterinary Medicine; Warsaw University of Life Sciences; Warsaw Poland
| | - Maciej Janeczek
- Department of Biostructure and Animal Physiology; Faculty of Veterinary Medicine; Wroclaw University of Environmental and Life Sciences; Wroclaw Poland
| |
Collapse
|
9
|
Puzzolo D, Pisani A, Malta C, Santoro G, Meduri A, Abbate F, Montalbano G, Wylegala E, Rana RA, Bucchieri F, Ieni A, Aragona P, Micali A. Structural, ultrastructural, and morphometric study of the zebrafish ocular surface: a model for human corneal diseases? Curr Eye Res 2017; 43:175-185. [PMID: 29111817 DOI: 10.1080/02713683.2017.1385087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE A morphological and morphometric study of the adult zebrafish ocular surface was performed to provide a comprehensive description of its parts and to evaluate its similarity to the human. MATERIALS AND METHODS The eyes of adult zebrafish were processed for light, transmission and scanning electron microscopy, and for immunohistochemical stain of corneal nerves; a morphometric analysis was also performed on several morphological parameters. RESULTS The corneal epithelium was formed by five layers of cells. No Bowman's layer could be demonstrated. The stroma consisted of lamellae of different thickness with few keratocytes. The Descemet's membrane was absent as the flat and polygonal endothelial cells directly adhered to the deepest corneal lamella. The immunohistochemical stain of neurofilaments failed to demonstrate corneal nerve fibers. The conjunctival epithelium was stratified, overlying the stroma formed by a subepithelial and a deep layer, this latter connected to the scleral cartilage. In the peripheral cornea and in the conjunctiva, many goblet and rodlet cells were observed. The morphometric analysis showed that the peripheral cornea epithelium was thicker when compared to the other parts of the ocular surface, with smaller superficial cells. Desmosomes and hemidesmosomes in the conjunctiva were significantly fewer in number than the other parts of the ocular surface. The stroma was thinner in the conjunctiva than in the cornea, while corneal lamellae were thicker in the intermediate stroma. CONCLUSIONS The zebrafish ocular surface showed significant differences compared to the human, such as the absence of Bowman's layer, Descemet's membrane and corneal nerve fibers, the reduced stromal thickness, and the presence of rodlet cells. On the basis of these original findings, it is suggested that the use of the zebrafish as a model for studying normal or pathological human corneas should be undertaken with particular caution.
Collapse
Affiliation(s)
- Domenico Puzzolo
- a Department of Biomedical Sciences , University of Messina , Messina , Italy
| | - Antonina Pisani
- a Department of Biomedical Sciences , University of Messina , Messina , Italy
| | - Consuelo Malta
- a Department of Biomedical Sciences , University of Messina , Messina , Italy
| | - Giuseppe Santoro
- a Department of Biomedical Sciences , University of Messina , Messina , Italy
| | - Alessandro Meduri
- a Department of Biomedical Sciences , University of Messina , Messina , Italy
| | - Francesco Abbate
- b Department of Veterinary Sciences, Laboratory of Zebrafish Neuromorphology , University of Messina , Messina , Italy
| | - Giuseppe Montalbano
- b Department of Veterinary Sciences, Laboratory of Zebrafish Neuromorphology , University of Messina , Messina , Italy
| | - Edward Wylegala
- c Clinical Department of Ophthalmology, School of Medicine with the Division of Dentistry in Zabrze , Medical University of Silesia , Katowice , Poland
| | - Rosa Alba Rana
- d Department of Medicine and Science of Aging , University of Chieti , Chieti , Italy
| | - Fabio Bucchieri
- e Department of Experimental Medicine, Section of Anatomy , University of Palermo , Palermo , Italy
| | - Antonio Ieni
- f Department of Human Pathology , University of Messina , Messina , Italy
| | - Pasquale Aragona
- g Department of Biomedical Sciences, Regional Referral Center for the Ocular Surface Diseases , University of Messina , Messina , Italy
| | - Antonio Micali
- a Department of Biomedical Sciences , University of Messina , Messina , Italy
| |
Collapse
|
10
|
Zhou HY, Cao Y, Wu J, Zhang WS. Role of corneal collagen fibrils in corneal disorders and related pathological conditions. Int J Ophthalmol 2017; 10:803-811. [PMID: 28546941 DOI: 10.18240/ijo.2017.05.24] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 03/23/2017] [Indexed: 01/24/2023] Open
Abstract
The cornea is a soft tissue located at the front of the eye with the principal function of transmitting and refracting light rays to precisely sense visual information. Corneal shape, refraction, and stromal stiffness are to a large part determined by corneal fibrils, the arrangements of which define the corneal cells and their functional behaviour. However, the modality and alignment of native corneal collagen lamellae are altered in various corneal pathological states such as infection, injury, keratoconus, corneal scar formation, and keratoprosthesis. Furthermore, corneal recuperation after corneal pathological change is dependent on the balance of corneal collagen degradation and contraction. A thorough understanding of the characteristics of corneal collagen is thus necessary to develop viable therapies using the outcome of strategies using engineered corneas. In this review, we discuss the composition and distribution of corneal collagens as well as their degradation and contraction, and address the current status of corneal tissue engineering and the progress of corneal cross-linking.
Collapse
Affiliation(s)
- Hong-Yan Zhou
- Department of Ophthalmology, China-Japan Union Hospital of Jilin University, Changchun 130033, Jilin Province, China
| | - Yan Cao
- Department of Ophthalmology, China-Japan Union Hospital of Jilin University, Changchun 130033, Jilin Province, China
| | - Jie Wu
- Department of Ophthalmology, China-Japan Union Hospital of Jilin University, Changchun 130033, Jilin Province, China
| | - Wen-Song Zhang
- Department of Ophthalmology, the Second Hospital of Jilin University, Changchun 130000, Jilin Province, China
| |
Collapse
|
11
|
Morphological description of limbal epithelium: searching for stem cells crypts in the dog, cat, pig, cow, sheep and horse. Vet Res Commun 2017; 41:169-173. [DOI: 10.1007/s11259-017-9676-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/12/2017] [Indexed: 12/26/2022]
|
12
|
Nautscher N, Bauer A, Steffl M, Amselgruber WM. Comparative morphological evaluation of domestic animal cornea. Vet Ophthalmol 2015; 19:297-304. [PMID: 26190143 DOI: 10.1111/vop.12298] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE This study described corneal morphology in different domestic animals using histological and immunohistochemical methods. Specifically, we evaluated the species-specific distribution pattern of cytokeratins (CKs) and aquaporins (AQPs) to assess their contribution to the strength and transparency of the cornea, respectively. PROCEDURES Corneal sections (2 μm thick) were obtained from 28 pigs, 11 cows, two goats, six horses, four dogs, and five cats and stained with hematoxylin-eosin and periodic acid-Schiff (PAS) reaction. Immunohistochemistry was also performed using CK1 to 3 and AQP1 and 5 antibodies. RESULTS Domestic animal corneas were composed of corneal epithelium, stroma, Descemet's membrane, and corneal endothelium. Bowman's layer was not detected using the PAS reaction. The three-layered epithelium was thinnest in carnivores and thickest in equines and bovines. CKs were demonstrated immunohistochemically in all species examined, especially in the most superficial layer of the corneal epithelium. CKs were more widely distributed in canine and feline corneal epithelial cell layers compared to other species. The corneal monolayer endothelium was immunostained with AQP1 in all species examined, and it was also present in stromal keratocytes in a species-specific manner. In contrast, AQP5 was exclusively localized to the corneal epithelium. Epithelial staining patterns varied markedly between species, and the widest distribution of AQP5 was demonstrated in feline epithelial cell layers. CONCLUSIONS Differences in the distribution of CKs and AQPs in various species suggest species differences in the maintenance of structural integrity and fluid balance.
Collapse
Affiliation(s)
- Nadine Nautscher
- Institute of Anatomy and Physiology of Domestic Animals, University of Hohenheim, Fruwirthstr. 35, D-70599, Stuttgart, Germany
| | - Achim Bauer
- Institute of Anatomy and Physiology of Domestic Animals, University of Hohenheim, Fruwirthstr. 35, D-70599, Stuttgart, Germany
| | - Martin Steffl
- Institute of Anatomy and Physiology of Domestic Animals, University of Hohenheim, Fruwirthstr. 35, D-70599, Stuttgart, Germany
| | - Werner M Amselgruber
- Institute of Anatomy and Physiology of Domestic Animals, University of Hohenheim, Fruwirthstr. 35, D-70599, Stuttgart, Germany
| |
Collapse
|
13
|
Ultrastructure Organization of Collagen Fibrils and Proteoglycans of Stingray and Shark Corneal Stroma. J Ophthalmol 2015; 2015:686914. [PMID: 26167294 PMCID: PMC4488252 DOI: 10.1155/2015/686914] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 05/24/2015] [Accepted: 06/02/2015] [Indexed: 12/02/2022] Open
Abstract
We report here the ultrastructural organization of collagen fibrils (CF) and proteoglycans (PGs) of the corneal stroma of both the stingray and the shark. Three corneas from three stingrays and three corneas from three sharks were processed for electron microscopy. Tissues were embedded in TAAB 031 resin. The corneal stroma of both the stingray and shark consisted of parallel running lamellae of CFs which were decorated with PGs. In the stingray, the mean area of PGs in the posterior stroma was significantly larger than the PGs of the anterior and middle stroma, whereas, in the shark, the mean area of PGs was similar throughout the stroma. The mean area of PGs of the stingray was significantly larger compared to the PGs, mean area of the shark corneal stroma. The CF diameter of the stingray was significantly smaller compared to the CF diameter in the shark. The ultrastructural features of the corneal stroma of both the stingray and the shark were similar to each other except for the CFs and PGs. The PGs in the stingray and shark might be composed of chondroitin sulfate (CS)/dermatan sulfate (DS) PGs and these PGs with sutures might contribute to the nonswelling properties of the cornea of the stingray and shark.
Collapse
|
14
|
Marzok MA, El-khodery SA. Intraocular pressure in clinically normal dromedary camels (Camelus dromedarius). Am J Vet Res 2015; 76:149-54. [DOI: 10.2460/ajvr.76.2.149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
15
|
Akhtar S. Ultrastructure alteration in the corneal stroma of hydrated camel corneoscleral button and corneal button. Microsc Res Tech 2012; 76:86-93. [PMID: 23077083 DOI: 10.1002/jemt.22140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 09/23/2012] [Indexed: 11/11/2022]
Abstract
PURPOSE To investigate the changes in the ultrastructural architecture of hydrated corneoscleral button (HCSB) and hydrated corneal button (HCB). METHOD Corneoscleral buttons (n = 4) and corneal buttons (n = 4) were hydrated in deionized water for 24 and 48 h and were fixed in 2.5% glutaraldehyde containing cuprolinic blue in sodium acetate buffer and processed for electron microscopy. The tissue was dehydrated and embedded in TAAB 031 resin. Normal CSB and CB were also processed using the same method. Ultrathin sections were stained with uranyl acetate and lead citrate. The sections were observed under JEOL 1400 transmission electron microscope. RESULTS In both HCSB and HCB, the lamellae were disorganized and proteoglycans (PGs) were degenerated and detached from the collagen fibrils (CFs). In the HCSB samples, interfibrillar spacing increased but the diameter of the CF had not changed compared with those in the normal tissue. Within the HCSB, the interfibrillar spacing in the posterior stroma was significantly higher compared with those in the anterior and middle stroma. In the HCB, both the interfibrillar spacing and CF diameter had significantly increased compared to those observed in both the HCSB and normal tissue. The CFs were severely damaged exhibiting very thin microfilaments within CFs. Remnants of the CFs were present in the stromal matrix. CONCLUSION Hydration of the cornea in both the HCSB and HCB increases the interfibrillar spacing in the anterior, middle, and posterior stroma. The CF in the HCB was enlarged and had degenerated. This could be due to penetration of water into the intermolecular spacing within the CF.
Collapse
Affiliation(s)
- Saeed Akhtar
- Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
| |
Collapse
|
16
|
Akhtar S. Effect of processing methods for transmission electron microscopy on corneal collagen fibrils diameter and spacing. Microsc Res Tech 2012; 75:1420-4. [PMID: 22648981 DOI: 10.1002/jemt.22083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 05/07/2012] [Accepted: 05/07/2012] [Indexed: 11/09/2022]
Abstract
INTRODUCTION The corneal tissue was processed in fixatives and embedded in resin for transmission electron microscopy to observe the ultrastructure of the collagen fibrils (CFs). The effect of these processing methods on the CF diameter and the interfibrillar spacing was studied. METHODS Four normal human corneal buttons were used for this study. A part of each cornea was fixed in 2.5% glutaraldehyde containing cuprolinic blue in sodium acetate buffer and embedded in spurr's resin (SpurrCB). A second part of each cornea was fixed in 2.5% glutaraldehyde + osmium tetroxide and embedded spurr's resin (SpurrOsm). The third part of each cornea was fixed in paraformaldehyde (4%) and embedded in LR White at 4°C (LRWhite). Ultrathin sections were stained with uranyl acetate and lead citrate. RESULTS In the tissue, fixed in SpurrCB, the diameter was 38.4 ± 5.9 nm and spacing between CF was 52.5 ± 5.3 nm. In the tissue fixed in SpurrOsm, the diameter was 28.37 ± 5.84 nm and spacing between CF was 45 ± 4.57 nm. In the tissue fixed in LR White, the CF diameter was 24 ± 2.3 nm and spacing between CF was 39.0 ± 4.2 nm. The diameters and interfibrillar spacing of the tissue processed by SpurrCB, SpurrOsm, and LRWhite were significantly different (P < 0.001) from one another. CONCLUSION Our study shows that there is a variation in the CF diameter and spacing depending on the method of fixation and embedding resins used. This needs to be considered when comparative studies using different methods are done.
Collapse
Affiliation(s)
- Saeed Akhtar
- Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
| |
Collapse
|