A novel cornea tissue scaffold material was prepared with N-vinly pyrrolidome (NVP) and a biodegradable crosslinking agent by radical polymerization, using azoisobutyronitrile (AIBN) as initiator. Water absorption test and contact angle measure were conducted, and the degradation process of material was investigated. The biocompatibility evaluation was carried out by implantation of material in the rabbits, and by cell culture. The water absorption was over 104%, the contact angle was lower than 41degrees, and the degradation speed in vitro kept steady. The results of implantation in the rabbits showed that the material was almost degraded 3 months later and lots of collagen and cornea stroma cells appeared in it,but there was no inflammation around it. The result of epithelial cells culture showed that the cells conglutinated on the material, but no remarkable cytotoxicity was noted.
Animals ; Biocompatible Materials ; chemistry ; Cornea ; cytology ; Epithelium, Corneal ; cytology ; Materials Testing ; Nitriles ; chemistry ; Prostheses and Implants ; Pyrrolidinones ; chemistry ; Rabbits ; Tissue Engineering

OBJECTIVE: To study the relationship between the postmortem interval (PMI) and the changes of DNA content in rabbit's cornea epithelial and endothelium. METHODS: Using the computerized image analysis to measure the DNA content in the cornea epithelial and endothelium of 105 rabbit's at every six hours during 72 hours after death. RESULTS: The degradation rate of DNA in nuclear has an apparent relationship in 72 hours after death of the rabbits. CONCLUSION The determination of the quantity of DNA in cornea nuclear is a new method to estimate the PMI accurately.
Animals ; DNA/analysis* ; Endothelium, Corneal/chemistry* ; Epithelium, Corneal/chemistry* ; Female ; Forensic Medicine ; Male ; Postmortem Changes ; Rabbits ; Signal Processing, Computer-Assisted ; Time Factors

In order to investigate the feasibility of the modified chitosan-gelatin crosslinked membrane (MC-Gel) and chitosan-gelatin crosslinked membrane (CS-Gel) to be a potential biomaterial for corneal regeneration, we evaluated their physicochemical properties and intraocular biocompatibility in this study. White light transmission and permeability of these membranes were detected. Results showed that white light transmission of both membranes was above 90% at 500 nm, which was similar to that of human cornea. The glucose, tryptophan and NaCl permeability of MC-Gel membrane and CS-Gel membrane was better than or similar to those of human cornea. The methylthiazol tetrazolium (MTT) assay was used to assess cell viability and proliferation. Also, interlamellar corneal transplantation was carried out to evaluate ophthalmic biocompatibility of MC-Gel membrane and CS-Gel membrane. Results indicated that MC-Gel membranes could support the proliferation of HCEC and displayed good intraocular biocompatibility when implanted into rabbits. No severe inflammatory reaction occurred after transplantation and the implanted MC-Gel membrane degraded completely 16 weeks post-operation. Due to its good physicochemical properties and biocompatibility, MC-Gel membrane could be a promising candidate material for corneal regeneration.
Animals ; Biocompatible Materials ; chemistry ; Cells, Cultured ; Chitosan ; chemistry ; Cornea ; cytology ; Corneal Injuries ; Cross-Linking Reagents ; Epithelium, Corneal ; cytology ; physiology ; surgery ; Gelatin ; chemistry ; Guided Tissue Regeneration ; methods ; Humans ; Membranes, Artificial ; Rabbits ; Regeneration ; Tissue Engineering ; methods ; Tissue Scaffolds

To study the possibility of using hydroxypropyl chitosan-based blend membranes as carriers of corneal cells in tissue engineering, we prepared three kinds of blend membranes labeled hydroxypropyl chitosan/chondroitin sulfate, hydroxypropyl chitosan/gelatin/chondroitin sulfate and hydroxypropyl chitosan/oxidized hyaluronic acid/chondroitin sulfate. The transparency, water content and ability of protein adsorption of the blend membranes were measured. To evaluate the cytocompatibility of the blend membranes with corneal epithelial cells, rabbit corneal epithelial cells were cultured on the surface of the carrier membranes. The morphological characteristics, cell adhesion, cell proliferation and the activity of lactate dehydrogenase (LDH) in the media were investigated. Three kinds of blend membranes had good optical transmittance, suitable water content and ability of protein adsorption. The results showed that the less injury was made to corneal epithelial cells by the hydroxypropyl chitosan/gelatin/chondroitin sulfate blend membrane than the others. This kind of membrane was favor of the growth and adhesion of corneal epithelial cells. The hydroxypropyl chitosan/gelatin/chondroitin sulfate blend membrane is a promising carrier of corneal cells and can be used in reconstruction of tissue engineered cornea.
Animals ; Biocompatible Materials ; chemistry ; pharmacology ; Cell Culture Techniques ; methods ; Cell Proliferation ; drug effects ; Cells, Cultured ; Chitosan ; chemistry ; Chondroitin Sulfates ; chemistry ; Epithelium, Corneal ; cytology ; Gelatin ; chemistry ; Membranes, Artificial ; Rabbits ; Tissue Engineering ; methods

Human amniotic membrane isolated from the placenta contained basement membrane components such as type IV collagen, laminin, and 6 and 4 integrins, all of which remained detectable while preserved in glycerin for one week. One month after the n-heptanol removal of the total corneal epithelium and the limbal lamellar keratectomy, all rabbit eyes carried features of limbal deficiency, including conjunctival epithelial ingrowth, vascularization and chronic inflammation. Ten control eyes then received a total keratectomy, and 13 experimental eyes received an additional amniotic membrane transplantation. Three-month follow-ups revealed that all control corneas were revascularized to the center with granuloma and retained a conjunctival phenotype. In contrast, in the experimental groups, 5 corneas became clear with either minimal or no vascularization; the rest had either mild peripheral (5) or total (3) vascularization and more cloudy stroma. Using monoclonal antibodies for epithelial markers and matrix components, we concluded that the success correlated with the return of a cornea-like epithelial phenotype and the preservation of the amniotic membrane, whereas the failure maintained a conjunctival epithelial phenotype and the amniotic membrane was either partially degraded or covered by host fibrovascular stroma. Measures taken to facilitate the former might prove this procedure clinically useful for ocular surface reconstruction.
Amnion/chemistry/*transplantation ; Animals ; Antibodies, Monoclonal ; Basement Membrane/chemistry/pathology ; Cornea/pathology/*surgery ; Corneal Neovascularization/pathology/*prevention & control/surgery ; Epithelium/pathology/surgery ; Extracellular Matrix Proteins/analysis ; Female ; Fluorescent Antibody Technique ; Humans ; Immunophenotyping ; Male ; Rabbits

OBJECTIVETo investigate the proliferation and differentiation of cultured corneal stem cells and determine the effect of corneal stem cells cultured on amniotic membranes on the limbal area for treating corneal burns.

METHODSThe proliferation and differentiation of corneal stem cells in vitro had been examined using colony-forming efficiency and immunohistochemistry. The stem cells had been cultured on amniotic membranes and transplanted to the limbal area for treating corneal burns.

RESULTSCorneal stem cells had a high proliferation capacity in primary and first passage, cytokeratin 3 was not expressed in primary culture but partly in first passage. The stem cells could proliferate to form cell layer on an amniotic membrane. When transplanted, stem cells could survive on limbus. After transplantation, ocular inflammation resolved, the cornea re-epithelialized, the stromal opacity reduced, the superficial neovascularity was lessened and the conjunctival fornix re-established.

CONCLUSIONSOcular surface conditions could be improved by allograft of corneal stem cells cultured on amniotic membranes.

Alkalies ; Amnion ; transplantation ; Animals ; Burns, Chemical ; surgery ; Cell Culture Techniques ; methods ; Cell Differentiation ; Cell Division ; Cell Transplantation ; methods ; Cells, Cultured ; Epithelium, Corneal ; chemistry ; cytology ; Eye Burns ; chemically induced ; surgery ; Graft Survival ; Humans ; Keratins ; analysis ; Limbus Corneae ; chemistry ; cytology ; Rabbits ; Stem Cells ; chemistry ; cytology ; Treatment Outcome