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1.
Joo Youn Oh Mee Kum Kim Hyun Ju Lee Jung Hwa Ko Won Ryang Wee Jin Hak Lee 《Veterinary ophthalmology》2009,12(Z1):50-56
Objective Although variations exist between species with respect to outcomes after cryopreservation, little is known about the differences in the susceptibility of the corneal stroma to cryoinjury. We performed this study to investigate freeze–thaw‐induced damage in keratocytes and collagen in rabbit, pig, and human corneas. Animals studied Rabbit, pig, and human. Procedures We prepared 250‐μm‐thick anterior stroma from rabbit, pig, and human corneas after scraping off the epithelium and endothelium. Each 250‐μm‐thick corneal stroma without epithelium was placed in a 50‐mL tube, frozen with liquid N2 for 15 min and taken out to thaw rapidly at 37 °C. This procedure of rapid freezing and thawing was repeated three times. Differences between the species with respect to cells and collagen structures were examined using hematoxylin–eosin (H&E) staining, terminal deoxynucleotidyl transferase‐mediated nick end labeling (TUNEL) assay, and transmission electron microscopy (TEM). We orthotopically transplanted the pig and rabbit corneal transplants after the triple freeze–thaw cycle into rabbit eyes and evaluated graft survival. Results On gross examination, rabbit corneas became opaque after the triple freeze–thaw procedure, while pig and human corneas remained transparent. Histologically, keratocytes were apoptotic on TUNEL assay and TEM in rabbit, pig, and human corneas. Collagen fibrils were fragmented and the arrangement of collagen fibrils was severely disturbed in rabbit corneas on H&E staining and TEM; collagen was well preserved in pig and human corneas. Rabbit corneal stroma underwent autolysis after transplantation, whereas the pig corneal stroma remained clear for 1 month. Conclusions Our study showed that rabbit corneal stroma was more susceptible to freeze–thaw injury than pig and human corneas. 相似文献
2.
Morreale RJ 《Clinical Techniques in Small Animal Practice》2003,18(3):145-151
The cornea is the anterior, transparent portion of the fibrous tunic of the eye. It is continuous with the sclera at a transition called the limbus. In healthy conditions, the transparency of the cornea is maintained by the smooth, nonkeratinized, squamous epithelium, which is further enhanced by the precorneal tear film, the lack of corneal vascularization or pigmentation, the size and regular arrangement of the collagen fibrils that make up the corneal stroma, and the relative dehydration of the cornea (which is maintained by the endothelium and epithelium). The cornea can respond to adverse stimuli through vascularization, pigmentation, fibrosis, accumulation of cellular or noncellular infiltrate, and/or edema. Because of these limited responses, routine diagnostic procedures are critical in the diagnosis and treatment of corneal disorders. This article discusses tests of the precorneal tear film, corneal staining procedures, culture and sensitivity, cytology, and a few other procedures that are performed less commonly or require specialized instrumentation. 相似文献
3.
Objective Although amniotic membranes of canine, feline, and equine species have some advantages as corneal transplantation material in many canine ocular diseases, their softness, thinness, and low availability can pose problems. As an alternative, the more abundant porcine amniotic membranes may be used. This paper describes the use of glycerin-preserved porcine amniotic membranes in corneal transplantation in eight normal dogs.
Method A 0.4-mm deep recipient bed in the axial cornea of the OS of all dogs was created using an 8-mm Barron radial vacuum trephine. The recipient bed was then filled with amnion, and the entire cornea was covered with another piece of the glycerin-preserved membrane. The ocular signs evaluated were corneal opacity and corneal vascularization. The dogs were euthanized on days 5, 10, 20, or 40 after surgery, and samples were collected to evaluate corneal thickness, parenchymal cell number, mean collagen fibril diameter, collagen fibril content and the glycosaminoglycan (GAG) ratio.
Results Corneal opacity was observed immediately after surgery. Restoration of corneal transparency, regression of corneal vascularization, and visualization of the pupil and iris were noted on day 40.
Conclusions The clinical observations were supported histologically by regained corneal thickness, parenchymal cell number, mean collagen fibril diameter, collagen fibril content, and GAG ratio, suggesting that this technique may be a novel method for the treatment of ocular surface disorders. 相似文献
Method A 0.4-mm deep recipient bed in the axial cornea of the OS of all dogs was created using an 8-mm Barron radial vacuum trephine. The recipient bed was then filled with amnion, and the entire cornea was covered with another piece of the glycerin-preserved membrane. The ocular signs evaluated were corneal opacity and corneal vascularization. The dogs were euthanized on days 5, 10, 20, or 40 after surgery, and samples were collected to evaluate corneal thickness, parenchymal cell number, mean collagen fibril diameter, collagen fibril content and the glycosaminoglycan (GAG) ratio.
Results Corneal opacity was observed immediately after surgery. Restoration of corneal transparency, regression of corneal vascularization, and visualization of the pupil and iris were noted on day 40.
Conclusions The clinical observations were supported histologically by regained corneal thickness, parenchymal cell number, mean collagen fibril diameter, collagen fibril content, and GAG ratio, suggesting that this technique may be a novel method for the treatment of ocular surface disorders. 相似文献
4.
Joo Youn Oh † ‡ Mee Kum Kim † ‡ Hyun Ju Lee † ‡ Jung Hwa Ko † ‡ Won Ryang Wee † ‡ Jin Hak Lee † ‡ 《Veterinary ophthalmology》2009,12(S1):50-56
Objective Although variations exist between species with respect to outcomes after cryopreservation, little is known about the differences in the susceptibility of the corneal stroma to cryoinjury. We performed this study to investigate freeze–thaw-induced damage in keratocytes and collagen in rabbit, pig, and human corneas.
Animals studied Rabbit, pig, and human.
Procedures We prepared 250-μm-thick anterior stroma from rabbit, pig, and human corneas after scraping off the epithelium and endothelium. Each 250-μm-thick corneal stroma without epithelium was placed in a 50-mL tube, frozen with liquid N2 for 15 min and taken out to thaw rapidly at 37 °C. This procedure of rapid freezing and thawing was repeated three times. Differences between the species with respect to cells and collagen structures were examined using hematoxylin–eosin (H&E) staining, terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay, and transmission electron microscopy (TEM). We orthotopically transplanted the pig and rabbit corneal transplants after the triple freeze–thaw cycle into rabbit eyes and evaluated graft survival.
Results On gross examination, rabbit corneas became opaque after the triple freeze–thaw procedure, while pig and human corneas remained transparent. Histologically, keratocytes were apoptotic on TUNEL assay and TEM in rabbit, pig, and human corneas. Collagen fibrils were fragmented and the arrangement of collagen fibrils was severely disturbed in rabbit corneas on H&E staining and TEM; collagen was well preserved in pig and human corneas. Rabbit corneal stroma underwent autolysis after transplantation, whereas the pig corneal stroma remained clear for 1 month.
Conclusions Our study showed that rabbit corneal stroma was more susceptible to freeze–thaw injury than pig and human corneas. 相似文献
Animals studied Rabbit, pig, and human.
Procedures We prepared 250-μm-thick anterior stroma from rabbit, pig, and human corneas after scraping off the epithelium and endothelium. Each 250-μm-thick corneal stroma without epithelium was placed in a 50-mL tube, frozen with liquid N
Results On gross examination, rabbit corneas became opaque after the triple freeze–thaw procedure, while pig and human corneas remained transparent. Histologically, keratocytes were apoptotic on TUNEL assay and TEM in rabbit, pig, and human corneas. Collagen fibrils were fragmented and the arrangement of collagen fibrils was severely disturbed in rabbit corneas on H&E staining and TEM; collagen was well preserved in pig and human corneas. Rabbit corneal stroma underwent autolysis after transplantation, whereas the pig corneal stroma remained clear for 1 month.
Conclusions Our study showed that rabbit corneal stroma was more susceptible to freeze–thaw injury than pig and human corneas. 相似文献
5.
Doughty MJ 《Veterinary ophthalmology》2012,15(2):71-80
Objective To investigate collagen fibrils of the equatorial sclera in relation to the age‐related changes in eye size in sheep. Animals studied Lambs and outbred ewes. Procedures Sheep eyes (three lamb and three from adult outbred ewes), presumed disease‐free, were processed for transmission electron microscopy (TEM) immediately postmortem. Tissue blocks from the equatorial region were sectioned across fibril bundles orientated along the equator. Micrographs including at least 500 fibrils were projected at 22 000× magnification for measures of fibril diameters (FDs). Results Lamb eyes were smaller than those of adult ewes but equatorial scleral thickness was only marginally less at 0.232 ± 0.013 vs. 0.254 ± 0.012 mm (P value not significant). Scleral tissue was composed of compacted bundles of collagen fibers that tended to be rounder in outer compared to being flatter in inner regions. In typical (normal) appearing regions, FDs were distinctly larger (68–410 nm) in outer sclera compared to inner sclera (63–281 nm). Outer sclera FDs were bimodal averaging 192 ± 58 nm, compared to unimodal distributions at inner locations averaging 156 ± 48 nm (P < 0.001). Some atypical regions, especially at outer‐mid sclera locations, were also noted where the FD distribution was bimodal but also included numerous microfibrils (<50 nm diameter), with similar appearances being found for both lamb and adult ewe eyes. Conclusions The equatorial sclera is a mixture of rounder versus flatter collagen fiber bundles, the former being more likely to be made up of a mixture of both smaller and larger fibrils, as compared to slightly smaller fibrils. 相似文献
6.
Enhanced expression of cyclooxygenase-2 in glaucomatous dog eyes 总被引：4，自引：1，他引：3
Objective Cyclooxygenase‐2 (COX‐2)‐derived prostaglandins (PGs) are shown to play important pathophysiologic roles in various disease states. Recently, the effectiveness of topical PGs in reducing intraocular pressure (IOP) has stimulated further interest in the physiologic function of COX‐2 and PGs in normal and glaucomatous eyes. Therefore, we investigated the cell‐type distribution and expression of COX‐2 in normal and glaucomatous dog eyes. Procedures Using isoform‐specific antibodies, we immunohistochemically evaluated COX‐2 expression in formalin‐fixed and paraffin‐embedded normal (n = 5) and glaucomatous (n = 17) dog eyes. Results In the normal eyes, only minimal COX‐2 immunoreactivity was observed in the ciliary epithelium. In the glaucomatous eyes, COX‐2 expression was further observed in the cornea and corneoscleral limbus. In the cornea, moderate to strong COX‐2 expression was observed in all corneal layers (epithelium, stromal cells and endothelium), with the greatest expression present in the epithelial layer. In the corneoscleral limbus area, COX‐2 immunoreactivity was noted in the stromal cells of sclera, trabecular meshwork and endothelial cells of the angular aqueous plexus. Conclusions Increased expression of COX‐2 in dog glaucomatous eyes suggests that COX‐2‐derived PGs may have a potential role in the pathogenesis of canine glaucoma. 相似文献
7.
Watanabe T Hosaka Y Yamamoto E Ueda H Sugawara K Takahashi H Takehana K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(9):855-860
The distribution pattern of collagen fibril diameter in the equine superficial digital flexor tendon (SDFT) is known to differ in central and peripheral areas of some regions. This study reports the essence of collagen fibril differences among different regions of the equine SDFT by transmission electron microscopic (TEM) and high-voltage electron microscopic observations and biochemical analysis. The distribution of large collagen fibrils increased but the density of collagen fibrils decreased from the proximal metacarpal region to the distal metacarpal region. Large collagen fibrils with an irregular cross-sectional profile were found more frequently in the middle metacarpal region than in other regions. Three-dimensional reconstruction of images of irregularly shaped collagen fibrils revealed that these fibrils are formed through fusion of small collagen fibrils with large ones. The amount of decorin, which reportedly inhibits the lateral fusion of collagen fibrils, decreased in the direction of the distal metacarpal region. On the other hand, the size of decorin gradually increased in the direction of the distal metacarpal region. These results suggest that regional differences in collagen fibril distribution and density of collagen fibrils in the SDFT are due, at least in part, to fusion of collagen fibrils and the concomitant regional differences in the amount and size of decorin. 相似文献
8.
Objective To describe morphologic features, pachymetry and endothelial cell density of the normal equine cornea and limbus by in vivo confocal microscopy.
Animals studied Ten horses without ocular disease.
Procedure The central and peripheral corneas were examined with a modified Heidelberg Retina Tomograph II and Rostock Cornea Module using a combination of automated and manual image acquisition modes. Thickness measurements of various corneal layers were performed and endothelial cell density determined.
Results Images of the constituent cellular and noncellular elements of the corneal epithelium, stroma, endothelium, and limbus were acquired in all horses. Corneal stromal nerves, the subepithelial nerve plexus, and the sub-basal nerve plexus were visualized. Cells with an appearance characteristic of Langerhans cells and corneal stromal dendritic cells were consistently detected in the corneal basal epithelium and anterior stroma, respectively. Median central total corneal thickness was 835 μm (range 725–920 μm) and median central corneal epithelial thickness was 131 μm (range 115–141 μm). Median central endothelial cell density was 3002 cells per mm2 (range 2473–3581 cells per mm2 ).
Conclusions In vivo corneal confocal microscopy provides a noninvasive method of assessing normal equine corneal structure at the cellular level and is a precise technique for corneal sublayer pachymetry and cell density measurements. A resident population of presumed Langerhans cells and corneal stromal dendritic cells was detected in the normal equine cornea. The described techniques can be applied to diagnostic evaluation of corneal alternations associated with disease and have broad clinical and research applications in the horse. 相似文献
Animals studied Ten horses without ocular disease.
Procedure The central and peripheral corneas were examined with a modified Heidelberg Retina Tomograph II and Rostock Cornea Module using a combination of automated and manual image acquisition modes. Thickness measurements of various corneal layers were performed and endothelial cell density determined.
Results Images of the constituent cellular and noncellular elements of the corneal epithelium, stroma, endothelium, and limbus were acquired in all horses. Corneal stromal nerves, the subepithelial nerve plexus, and the sub-basal nerve plexus were visualized. Cells with an appearance characteristic of Langerhans cells and corneal stromal dendritic cells were consistently detected in the corneal basal epithelium and anterior stroma, respectively. Median central total corneal thickness was 835 μm (range 725–920 μm) and median central corneal epithelial thickness was 131 μm (range 115–141 μm). Median central endothelial cell density was 3002 cells per mm
Conclusions In vivo corneal confocal microscopy provides a noninvasive method of assessing normal equine corneal structure at the cellular level and is a precise technique for corneal sublayer pachymetry and cell density measurements. A resident population of presumed Langerhans cells and corneal stromal dendritic cells was detected in the normal equine cornea. The described techniques can be applied to diagnostic evaluation of corneal alternations associated with disease and have broad clinical and research applications in the horse. 相似文献
9.
The fine structure of the tapetum lucidum of the domestic cow was studied by electron microscopy. In this ungulate the reflective layer is a tapetum fibrosum situated in the choroid and mainly restricted to the superior fundus. The tapetum is composed of a large array of fine extracellular collagen fibrils separated into lamellae by fibrocytes. The collagen fibrils display the normal cross-striations of native collagen, are 0.2 μm in diameter and are arranged in a hexagonal pattern with a center-to-center spacing of about 0.2 μm. The diameter and spacing of these fibrils is consistent with the constructive interference of reflected light. A vascular lamella adjacent to the retinal epithelial layer contains the choriocapillaris and some irregularly arranged collagen fibrils. The tapetum is pierced by blood vessels which supply the choriocapillaris. Over the tapetum the retinal epithelium is non-pigmented while in nontapetal regions this layer is pigmented. The choriocapillaris is not indented into the retinal epithelium as is the case in species with a tapetum cellulosum. 相似文献
10.
Lamellar keratoplasty with a graft of lyophilized acellular porcine corneal stroma in the rabbit 总被引：1，自引：0，他引：1
Objective To evaluate the efficacy of lamellar keratoplasty in the rabbit using a graft of lyophilized acellular porcine corneal stroma (APCS). Animal studied Twelve adult 2–2.5 kg Zealand white rabbits were studied. Procedure The cell components of the porcine cornea were removed by the means of enzymatic digestion, freezing, and thawing and then APCS was lyophilized. The 6.5 mm diameter APCS was implanted on a 6.0‐mm diameter keratectomy wound each of 12 rabbits. The postoperative clinical and histological evaluations were performed in the early, intermediate, and late periods. Results All corneal wounds healed. Ten of the 12 grafts of APCS were integrated completely with the receptive cornea except two grafts scraped partially off by the eyelid. The blepharospasm, ocular discharge, and edema of the cornea were marked 1 week after transplantation. New vessels invaded the graft after week 2 and regressed after week 8. The cornea became transparent gradually. The histological evaluation showed that the epithelium on the graft stratified normally post surgery. The keratocytes of the recipient grew into the graft and were proliferative at week 4. The inflammatory cells and new vessels were observed before week 8. The fibrosis in the graft was revealed at week 4 and lessened at week 8. The histological structure of the cornea after surgery was similar to the normal cornea at week 32. Conclusions APCS can recover the integrity of the rabbit's cornea and become transparent in vivo. APCS is an effective graft for lamellar keratoplasty in the rabbit. 相似文献
11.
A morphometric ultrastructural study was performed to confirm the presence of an abnormality of the collagen fibrils in a rabbit with a connective tissue defect similar to Ehlers-Danlos syndrome. Median fibril diameter and perimeter were not altered but their ranges were significantly increased. As indicated by the median fibril ‘form factor’, fibrils were significantly more irregular in shape; the range of irregularity in shape was also increased. Fibril periodicity was unchanged. The results are discussed in relation to collagen fibril structure and fibril abnormalities in similar diseases in man and other animals. 相似文献
12.
Edwards LJ Goodship AE Birch HL Patterson-Kane JC 《American journal of veterinary research》2005,66(4):564-568
OBJECTIVE: To determine whether specific treadmill exercise regimens would accelerate age-related changes in collagen fibril diameter distributions in the common digital extensor tendon (CDET) of the forelimbs of young Thoroughbreds. ANIMALS: 24 female Thoroughbreds. PROCEDURE: Horses were trained for 18 weeks (6 horses; short term) or 18 months (5 horses; long term) on a high-speed treadmill; 2 age-matched control groups (6 horses/group) performed walking exercise only. Horses were (mean +/- SD) 24 +/- 1 months and 39 +/- 1 months old at termination of the short-term and long-term regimens, respectively. Midmetacarpal CDET specimens were obtained and processed for transmission electron microscopy. Diameter and area of at least 1,000 collagen fibrils/specimen were measured by use of computerized image analysis. Mass-average diameter (MAD) of collagen fibrils and collagen fibril index were calculated for each horse. RESULTS: Collagen fibril MAD for the older horses was significantly less than that for the younger horses. Exercise did not significantly affect fibril diameter or distributions in either age group, and collagen fibril index did not differ significantly between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Age-related reduction in collagen fibril MAD agreed with findings for other tendons and species. Training did not accelerate age-related change in the CDET in contrast to a reported decrease in collagen fibril MAD in the superficial digital flexor tendon of horses trained long term. Our results support the concept that the functionally distinct nature of the CDET and superficial digital flexor tendon in horses results in fundamentally different responses to high-speed exercise regimens. 相似文献
13.
14.
Normal canine hip cartilage was compared with cartilage from the degenerative lesions found in young dogs with canine hip dysplasia. The upper 0.5 mm of normal cartilage was characterized. Four distinct layers or zones were found: a layer of fine fibrous material covering the surface, a layer (surface layer) of small (32 nm diameter or less) collagen fibrils tightly packed in bundles and oriented parallel to the surface, a layer (upper layer) or less tightly packed collagen fibrils oriented mostly parallel to the surface with about 33% of the fibrils 64 nm or more, and a layer (intermediate layer) of randomly oriented fibrils with more than 50% of the fibrils 64 nm or larger. Fibril density was high in the surface layer and decreased with depth into the cartilage. In a moderately advanced lesion of degenerative cartilage, there was a layer of amorphous material over the surface. The tightly packed surface layer of small fibrils was absent. The surface itself was uneven and fissued. At depths from the surface comparable to the upper and the intermediate layers in normal cartilage, the proportion of large fibrils was less than in normal cartilage. The overall density of fibrils in degenerative cartilage increased with depth into the tissue. Cells flattened parallel to the surface, with relatively large nuclei, were found in the upper layer of normal cartilage. Cells in the intermediate layers were larger and round. The oblong cells of the upper layer of normal cartilage were not found in any layer of degenerative cartilage. Differences between cells in other layers of normal and degenerative cartilages were minimal. A model for the arrangement of chondrocytes and collagen fibrils for normal and degenerative cartilage was proposed. Ultrastructural changes in degenerative cartilage were prominent in the upper 0.5 mm of cartilage. These changes were changes in the number of collagen fibrils/mum-2 and a change from a characteristic pattern of collagen fibril diameters and orientation found in normal tissue. 相似文献
15.
Nagayasu A Nakamura T Yamato O Tsuzuki K Hosaka Y Ueda H Tangkawattana P Takehana K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(9):881-886
GM1 gangliosidosis is one of the inherited metabolic lysosomal storage disorders characterized by neurological symptoms caused by beta-galactosidase deficiency and consequent accumulation of GM1 ganglioside in neuronal cells. Shiba dogs affected with GM1 gangliosidosis have been found to suffer from corneal opacity. In our morphological analysis, keratocyte enlargement was induced by abnormal intracellular accumulation of neutral carbohydrates, resulting in the loss of normal arrangement of collagen fibrils in the opaque cornea was found to be associated with the disorder. We therefore conclude that corneal opacity in this Shiba dog with GM1 gangliosidosis may be caused by neutral carbohydrate accumulation in lysosomes, swelling and dysfunction of keratocytes, and subsequent irregular arrangement of collagen fibrils in the corneal proper substance. 相似文献
16.
Kodama R Yang X Araki T Sato M Iwashige S Tanigawa Y Uchimura M Ishimaru K Sasaki Y Kamimura Y Maeda H 《Journal of toxicologic pathology》2010,23(1):53-58
In a seven-year-old male cynomolgus monkey, erythema of the upper eyelid and forehead and corneal opacity, edema and conical protrusion in the eye were observed. At necropsy, ophthalmological and serological examinations revealed binocular corneal opacity and conical protrusion and a high IgE level, respectively. Thinning of the epithelium and stroma of the cornea were noted histopathologically. At the center of the corneal epithelium, the number of epithelial cells was reduced, their cytoplasm was poorer and the basal cells were flatter than at the periphery. Bowman's membrane was folded with partial loss or breakage. Collagen fibers were compacted or disarranged, and the keratocytes were increased in the stroma, with focal pyknosis or loss of the endothelium and folding of Descemet's membrane. Electron microscopical examination revealed atrophy of the corneal epithelial basal cells. This is the first report of a case of keratoconus in a cynomolgus monkey. 相似文献
17.
The collagen fibrils in fowl medullary bone 总被引：1，自引：0，他引：1
J K Candlish 《British poultry science》1971,12(1):111-117
Medullary bone from the femurs of laying fowls was examined by electron microscopy, with particular reference to the nature and environment of its collagen fibrils. The collagen fibrils appeared to have a preferred orientation along the long axis of the bone. There were no clear‐cut cyclic changes in the fibril diameters during egg calcification. The tissue was rich in mucopolysaccharides, visualised as strands or sheets connecting the fibrils. Lysis of the fibrils appeared to be associated with osteoclasts rather than osteocytes. 相似文献
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19.
Corneal sequestrum was diagnosed upon clinical examination of 12 cats. The cornea of seven were examined histologically and had focal necrosis and inflammation of the stroma and epithelium. As the simple excision of the corneal lesions had been unsuccessful in two of the cats, repair of these was effected by construction of a tarso-conjunctival pedicle flap after the excision of the sequestrum. 相似文献
20.
Corneal sequestrum was diagnosed upon clinical examination of 12 cats. The cornea of seven were examined histologically and had focal necrosis and inflammation of the stroma and epithelium. As the simple excision of the corneal lesions had been unsuccessful in two of the cats, repair of these was effected by construction of a tarso-conjunctival pedicle flap after the excision of the sequestrum. 相似文献