BACKGROUNDThough there have been various methods for harvesting and preserving descemet membrane (DM) and intact endothelium, there is no literature about the morphological evaluation of endothelium after graft preparation for descemet membrane endothelial keratoplasty (DMEK). The aim of this study was to establish and improve a simple method for preparing, preserving, and morphologically evaluating the donor graft for DMEK.

METHODSTo obtain a donor graft, an air bubble was formed by injecting a 29 G needle with 1 ml sterile air into a small edge created outside the Schwalbe line. Another needle was inserted into the bubble through the stroma to aspirate the air or replace half the air with organ culture medium. Trypan blue was used to mark the location for small incision to improve the success rate. Frozen sections were stained with hematoxylin and eosin (HE). Based on the air bubble, DM grafts were divided into four groups: group A (normal control), graft without any operative technique; group B, graft with zero-pressure air bubble; group C, graft with full-pressure air bubble; group D, graft with half-pressure air bubble. The four groups of grafts were preserved for 24 hours to observe the effect of bubbles on cells. The gross and ultrastructure morphologies were evaluated using alizarin red and scanning electron microscopy (SEM), respectively.

RESULTSDonor grafts were harvested via the air bubble technique, facilitated by prior trypan blue staining. HE-stained sections revealed a pure graft without stroma. There were no significant changes under light microscope. In group A, SEM revealed a confluent layer of polygonal endothelium with distributed microvilli exhibiting characteristics of interdigitating junctions. In group B, intercellular borders became thinner. In group C, interdigitations were almost flat and microvilli were observed less frequently. In group D, other than less microvilli, there were minimal changes.

CONCLUSIONSThe donor graft preparation method appears to be effective and convenient. Properly decreasing the air pressure could protect and preserve the endothelium.

Animals ; Descemet Membrane ; cytology ; Descemet Stripping Endothelial Keratoplasty ; methods ; Endothelium, Corneal ; cytology ; Rabbits ; Tissue Donors

Primary and secondary corneal endothelial decompensation leads to stromal edema, corneal opacity and loss of visual acuity. The pathogenesis of corneal endothelial decompensation is that adult corneal endothelium in vivo lacks of a robust proliferative response to injury, does not divide sufficiently to replace the lost cells. Previous studies indicate that cell-cell contact inhibition and transforming growth factor-beta2 (TGF-β2) in aqueous humor may be responsible for maintaining human endothelial cells in a non-replicative state in vivo. The results of the experimental investigation by using immunofluorescent staining of the cell cycle-associated proteins and cell proliferation marker Ki67 in corneal endothelium indicate that human corneal endothelial cells in vivo are arrested in the G1-phase and have not exited from the cell cycle. Successful outgrowth in culture of human corneal endothelial cells in vitro and the establishment of the immortalized human endothelial cell line, provide strong evidence that corneal endothelial cells retain proliferative capacity. Experiments with cell culture ex vivo demonstrate that corneal endothelial cells cultured from young donors grow more robustly than those from older donors, and cells cultured from peripheral area of corneas show greater cell density than central regions. Studies have demonstrated that in vitro human corneal endothelia undergo mitotic changes in response to stimulation of growth promoting agents, such as growth factors, EDTA and extracellular matrix. Identification of corneal endothelial stem cells and isolation and culture of human endothelial precursor cells in vitro will be beneficial for further investigation regarding the mechanism of corneal endothelial regeneration as well as corneal endothelial cells in vitro culture.
Aqueous Humor ; metabolism ; Cell Count ; Cell Culture Techniques ; Cell Cycle ; Cell Proliferation ; Cells, Cultured ; Contact Inhibition ; Endothelium, Corneal ; cytology ; Humans ; Stem Cells ; Transforming Growth Factor beta2 ; metabolism

BACKGROUNDTrabecular meshwork (TM) cell volume may be an important determinant of aqueous humor outflow in the eye. This study aimed to evaluate the role of HepII domain peptides V on corneal permeability, corneal endothelial cells, intraocular pressure (IOP) and morphology of trabecular meshwork in rats.

METHODSThe IOP of rat eyes was measured before and 3, 5, 7 and 8 hours after topical delivery of HepII domain peptides V through intracameral injections. The peptide's concentration in aqueous humor was assessed by high performance liquid chromatography (HPLC). The shape and density of endothelial cells were observed by laser confocal microscopy 8 hours, 3 and 14 days after intracameral injections of HepII domain peptides V. The morphological changes in TM of rat eyes were assessed by transmission electron microscopy (TEM).

RESULTSIntracameral injection of HepII domain peptides V significantly (P < 0.001) decreased IOP by (5.71 ± 2.10) mmHg in rats at 5 hours after injection. There were no obvious changes of the shape and the density of corneal endothelial cells. In addition, morphological changes in the TM of rats were observed including the expansion of intercellular spaces in the juxtacanalicular meshwork, removal of extracellular material, cellular relaxation, and cytoskeleton reorganization.

CONCLUSIONSHepII domain peptides V could not penetrate cornea and was safe to corneal endothelial cells. HepII domain peptides V could significantly decrease IOP in rat probably by disorganizing actin cytoskeleton and cell-junction in the TM.

Animals ; Chromatography, High Pressure Liquid ; Cornea ; cytology ; drug effects ; ultrastructure ; Endothelium, Corneal ; drug effects ; ultrastructure ; Female ; Fibronectins ; chemistry ; pharmacology ; Intraocular Pressure ; drug effects ; Male ; Microscopy, Confocal ; Microscopy, Electron, Transmission ; Rats ; Rats, Sprague-Dawley ; Trabecular Meshwork ; drug effects ; ultrastructure

OBJECTIVETo investigate the biological function of platelet-derived growth factor B (PDGF-B) on the survival and proliferation of cat corneal endothelial cells so as to provide bases for further studies of its role in wound repair and its clinical application.

METHODSTotal RNA was extracted from the placenta tissues of healthy pregnant women undergoing hysterotokotomy and PDGF cDNA was obtained with reverse transcription-polymerase chain reaction (RT-PCR). The prokaryotic expression vector pET-PDGF-B was constructed and expressed the recombinant PDGF-B in Escherichia coli (E. coli) BL21 (DE3). After purification and refolding on Ni2+-chelation affinity chromatography (NTA) column, it was used to culture cat corneal endothelial cells. Cell proliferation was tested by modified tertrazolium salt (MTT) and flow cytometer. And the morphologic change and the ultrastructure were observed under an inverted phase contrast microscope, a scanning electron microscope and a transmission electon microscope, respectively.

RESULTSPDGF-B chain peptide (PDGF-BB) gene was successfully inserted into the prokaryotic expression vector, pET-28a (+). The purified recombined protein pET-PDGF-B showed a single band on sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE) with the molecular weight of about 27 u, which was in agreement with the deduced value. MTT and flow cytometry showed that PDGF-BB promoted the survival and proliferation of cat corneal endothelial cells.

CONCLUSIONSThe construction of recombinant prokaryotic expression vector pET-PDGF-B and the preparation of PDGF-BB protein provide a foundation for further study of the function of PDGF-BB and producing biological PDGF-BB protein. The expressed PDGF-BB promotes the proliferation of cultured cat corneal endothelial cells.

Animals ; Cats ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cloning, Molecular ; Endothelium, Corneal ; cytology ; drug effects ; Humans ; Immunohistochemistry ; Phosphopyruvate Hydratase ; analysis ; Protein Folding ; Proto-Oncogene Proteins c-sis ; chemistry ; genetics ; pharmacology ; Recombinant Proteins ; biosynthesis ; isolation & purification ; pharmacology ; Wound Healing ; drug effects

Un-transfected rabbit corneal endothelial cells (RCECs) were cultivated, using chitosan blend membrane 4ha (chitosan-hyaluronic acid), 631ha (chitosan-hyaluronic acid) and 631s (chitosan-chondroitine sulfate) as scaffold carriers. Their biocompatibilities were studied in regard to cell adherence, morphological changes, growth status and monolayer forming abilities. The results indicated that RCECs cultivated on 4ha and 631ha carriers tended to be aggregated and even desquamated to some extent in local areas, and even more severely on 631ha carrier. And the RCECs cultivated on 631ha carrier could form almost a monolayer 48h later, and those on 4ha carrier could not. Contrarily, the RCECs cultivated on 631s carrier were evenly distributed and were in good status of growth with a good adherence and fibroblast-like morphology which could form almost a monolayer 48h later. And a complete monolayer was formed and was tightly attached to the 631s carrier 72h later. From the above results, it can be concluded that 631s carrier is most probably an ideal scaffold carrier for RCEC cultivation. 631s carrier may have the potential for use in the development of tissue-engineered rabbit corneal endothelium.
Animals ; Biocompatible Materials ; chemistry ; Cell Adhesion ; Cell Culture Techniques ; Cell Line ; Cells, Cultured ; Chitosan ; chemistry ; Endothelium, Corneal ; cytology ; Hyaluronic Acid ; chemistry ; Membranes, Artificial ; Rabbits ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry

OBJECTIVETo evaluate the feasibility of using cultured corneal endothelial cell (CECs) transplantation for cornea endothelium cell destruction with Gelatin membrane as the carrier in rabbits.

METHODSThe cultured CECs were labeled by Brdu and subcultured in vitro on glutaraldehyde-fixed Gelatin membranes and then the membranes were glued by alpha-cyanoacrylate alkyl to 7.00 mm autologous rabbit corneal bottons whose endothelium were mechanically removed previously. The buttons were sutured in place. With this method the right eyes of 21 rabbits were transplanted with CECs, and the right eyes of another 17 rabbits were transplanted with non-cells carrier as controls. The rabbits were bred and observed by slit microscopy and confocal microscopy at 1, 2, 4, 8, and 12 weeks after surgeries. Also, introcular pressure and corneal thickness were measured by Perkin's tonometer and ultrasonic pachymeter. After 12 weeks, all the animals were sacrificed and the grafts were examined by light microscopy and electronic microscopy.

RESULTSCECs grew well on the gelatine memberane, and formed confluent monolayers in 3-5 days; the cell density reached as high as 2700 cells/mm2. After 2 weeks of operation, all corneal buttons were edema and began to be opaque. The control eyes remained opaque throughout the observation period. In eyes with CECs transplanted, the grafts began to be clear and thin 4 weeks after operation. The cell density of grafts decreased along with time, and the mean cell density of CECs transplantation buttons was (2023.3 +/- 330.3) cells/mm2 12 weeks after operation. The transplanted cells were stained with the anti-Brdu monoclonal antibody.

CONCLUSIONIt is feasible to culture and translate CECs with the Gelatin membrane.

Animals ; Cells, Cultured ; Corneal Endothelial Cell Loss ; pathology ; therapy ; Endothelial Cells ; transplantation ; Endothelium, Corneal ; cytology ; Rabbits

PURPOSE: To establish the immortalized human corneal endothelial cell line (IHCEn) by transducing human papilloma virus (HPV) 16 E6/E7 oncogenes, and to identify their characteristics when cultivated on a lyophilized human amniotic membrane (LAM). METHODS: Primary human corneal endothelial cells (PHCEn) were infected using a retroviral vector with HPV 16 E6/E7, and transformed cells were clonally selected by G418. Growth properties and characteristics of IHCEn were compared with PHCEn by cell counting and RT-PCR of VDAC3, SLC4A4, CLCN3, FGF-1, Col IV, and Na+/K+ ATPase. IHCEn were cultured on LAM. Messenger RNA expressions of VDAC3, CLCN3, and Na+/K+ ATPase, and protein expressions of Na+/K+ ATPase and Col IV in IHCEn cultivated on LAM were investigated by RT-PCR, immunofluorescence, and immunohistochemical staining, respectively. RESULTS: Successful immortalization was confirmed by stable expression of HPV 16 E6/E7 mRNA by RT-PCR, and IHCEn exhibited typical corneal endothelial morphology. Doubling time of IHCEn was 30.15+/-10.96 hrs. Both IHCEn and PHCEn expressed VDAC3, CLCN3, SLC4A4, FGF-1, Col IV, and Na+/K+ ATPase. IHCEn cultivated on LAM showed stronger expression of VDAC3, CLCN4, and Na+/K+ ATPase mRNA than on plastic culture dish. Immunohistochemical staining and immunofluorescence revealed the positive expression of Na+/K+ ATPase and Col IV. CONCLUSIONS: IHCEn were successfully established, and LAM is a good substrate for the culture of human corneal endothelial cells.
Transfection ; Reverse Transcriptase Polymerase Chain Reaction ; Repressor Proteins/genetics/*pharmacology ; RNA, Messenger/genetics ; Protein-Tyrosine Kinases ; Oncogene Proteins, Viral/genetics/*pharmacology ; Immunohistochemistry ; Humans ; Gene Expression Regulation, Viral ; Freeze Drying ; Endothelium, Corneal/*cytology/drug effects/metabolism ; Cell Line, Transformed ; Cell Count ; Amnion

In order to investigate the effect of nerve growth factor (NGF) on the proliferation of rabbit corneal endothelial cells and epithelial cells, the in vitro cultured rabbit corneal endothelial cells and epithelial cells were treated with different concentrations of NGF. MTT assay was used to examine the clonal growth and proliferation of the cells by determining the absorbency values at 570 nm. The results showed that NGF with three concentrations ranging from 5 U/mL to 500 U/mL enhanced the proliferation of rabbit corneal endothelial cells in a concentration-dependent manner. 50 U/mL and 500 U/mL NGF got more increase of proliferation than that of 5 U/mL NGF did. Meanwhile, 50 U/mL and 500 U/mL NGF could promote the proliferation of the rabbit corneal epithelial cells significantly in a concentration-dependent manner. However, 5 U/mL NGF did not enhance the proliferation of epithelial cells. It was suggested that exogenous NGF can stimulate the proliferation of both rabbit corneal endothelial and epithelial cells, but the extent of modulation is different.
Cell Proliferation/*drug effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Endothelium, Corneal/*cytology ; Epithelium, Corneal/*cytology ; Nerve Growth Factor/*pharmacology

The goal of this study was to evaluate the function of hyaluronic acid (HA) on the active oxygen release from polymorphonuclear leukocytes (PMNs) and the protective effect of bovine corneal endothelial cells (BCEC) from activated PMNs. We used HA with three different molecular weights (MW 700, 000, 2, 000, 000, and 4, 000, 000) and five different concentrations (0, 0.1, 1, 2, and 3 mg/ml). We evaluated the amount of released superoxide from activated PMNs by using dismutase-inhibitable ferricytochrome C reduction. To compare the property and protective effect of HA with those of other viscoelastic substances, we used the same concentration of methylcellulose. HA suppressed superoxide release from PMNs and protected BCEC from activated PMNs in a dose-dependent, rather than a molecular weight-dependent, manner. The effect of HA reached almost a plateau at concentration above 2 mg/ml. However, methylcellulose, another viscoelastic substance, showed a similar effect. Therefore, it seems that the suppression of superoxide released from PMNs is not a property that is unique to HA, but is a general property of viscoelastic substances. Our results indicate that the action mechanism of HA proceeds not only through cell surface HA-receptor. We think that HA also acts as a physical barrier and/or a scavenger of superoxide.
Animals ; Cattle ; Cell Survival ; Cells, Cultured ; Comparative Study ; Cytochromes c/metabolism ; Cytoprotection ; Dose-Response Relationship, Drug ; Endothelium, Corneal/cytology/*drug effects ; Humans ; Hyaluronic Acid/*pharmacology ; Methylcellulose ; Molecular Weight ; *Neutrophil Activation ; Neutrophils/*drug effects/metabolism ; Superoxides/*metabolism

OBJECTIVETo demonstrate the molecular expression of carbonic anhydrase IV (CA IV) in rabbit corneal endothelium.

METHODSReverse transcriptase polymerase chain reaction (RT-PCR) was performed using cultured and fresh rabbit corneal endothelial total RNA and specific primers for CA IV. The RT-PCR product was subcloned and sequenced. Immunoblotting and indirect immunofluorescence staining were performed to detect protein expression and distribution of CA IV using fresh and cultured rabbit corneal endothelium and rat anti-CA IV polyclonal antibody.

RESULTSRT-PCR screening gave positive bands at the predicted size for CA IV from fresh and cultured rabbit corneal endothelium. Sequencing further confirmed the identity of CA IV in corneal endothelium. Immunoblotting analysis showed a single band at 52 kDa for freshly isolated and cultured endothelial cells. Indirect immunofluorescence staining revealed an apparent positive staining in cultured endothelial cells.

CONCLUSIONCarbonic anhydrase IV is expressed in rabbit corneal endothelium, which could contribute to the transendothelial HCO(3)(-) flux that is necessary to maintain corneal hydration and transparency.

Animals ; Base Sequence ; Bicarbonates ; metabolism ; Carbonic Anhydrase IV ; analysis ; genetics ; Cells, Cultured ; Endothelium, Corneal ; cytology ; enzymology ; Fluorescent Antibody Technique, Indirect ; Molecular Sequence Data ; RNA, Messenger ; analysis ; Rabbits